Yeah. the scariest I ever had to deal with was an exhaust manifold stud that broke off in an aluminum cylinder head. I was able to drill into the stud itself and then use an extractor tool on the end of a power drill to remove it, but that was about the most stressful damaged fastener I've had to contend with. Honorable mention was a valve rocker shaft, but the fastener was brand new and so was the head, so when it broke I was able to extract it by just turning it with a pick.
Reminds me of Jeremy Clarkson on Top Gear telling people, if I recall correctly, that if they did not like something, then please, do feel free to keep it to yourself.
"I could have just overdubbed the audio, and no one would have been the wiser... BUT THAT'S NOT GENUINE!" Right on dude! That's the way these type of videos should be done!
Some engineer in Japan in their 70s or 80s, if they were to view this would be extremely happy with their work and your love and care over something so constructed. Thank you for your great videos and narration. Please, please keep such great content and preservation alive.
This video made me take another crack at fixing my first record player! I'd given up on the thing and replaced it with a lovely German turntable from the '80s. Now my first player is not only working, but I've restored it back to it's original home in my booth. Thanks for the indirect inspiration, my dude!
When he got to the point where it looked like the whole mech would have to come apart just to replace that belt, I was like... ok I would seal this thing up and go on to something else.
I am actually glad, that he has no repair shop near by. This surely was a lot of work, but it is far, far more interesting than "I paid 200£ to get it all fixed"
I’ve been fiddling with repairing a ct-f2121. It’s astounding how fine the tolerances are in the belts and tensions in these mechanisms. Good call on the rubber o rings, I did the same. Well done for persevering!
Tech Moan : I'm not qualified and I dont really know what I'm doing. Does all research, takes down, diagnoses, repairs, knows all the names and other stuff I wouldnt even think of.
@@anonUK he really understands more than he credits himself for mostly due to being largely self taught. He definitely understands mechanics of fly wheels and especially rubber belts and rings.
What's interesting to me is that even with all he's demonstrably capable of, he still has the bits (e.g. at 33:06) where he's got the belief that he's at his limits. Which is maybe just accurate, as far as current knowledge... but I'm sure he could learn more, and hope he might. :)
Frank Barone The old tube stuff is what gets me going. Current projects are a 1926 tabletop tube shortwave radio (“farm battery” type, so I need to build a power supply, as well as an output converter since it’s made for old-style speakers) and a 1947 New Zealand tabletop shortwave radio. I chose big projects there, considering how much work is to be done to make them functional. But tubes are always so much fun. I don’t _really_ know what I’m doing, like Matt, but somehow figure it out. If you can solder and read a schematic, you can often figure it out as you go along. It also helps that I’ve collected a series of old (as far back as 1910 or so) electronics, electrical & radio repair books with a ton of stuff on tunes. Amazing resources if you can find them that aren’t online or digitized anywhere. A lot of lost knowledge.
Your perseverance is really inspiring. You demonstrate a simple method for attacking a problem: have at it until you hit a wall, then step back for a while and take a breath, then dive in again. Like Einstein said: "It's not that I'm so smart. It's just that I stay with problems longer."
When I saw the length of this video i thought 'oef, this too long, i could be seeing a lot of other interesting videos in the same time'. But i gave it a try and, as always, i found this again a very entertaining video. The way you explain your struggles, keep your honesty and not boast about your accomplishments make your videos very genuine en make you a very likable guy. Thank you very much for this half hour of technical meditation.
Hey Matt; I've never worked on this particular deck, but I've seen many others from the late 70s and early 80s with electronic auto-stop faults and they've generally been down to bad electrolytic capacitors in the auto-stop circuit. On the diagram you showed in the video at around 32:40 I would say that the prime suspect would be C352 (100uF/35V). Once this component starts leaking, it will be unable to fully charge, possibly to the point where the voltage across D353 is insufficient to trigger switch on transistor Q352. This could prevent the auto-stop from engaging. The auto-stop circuit is not especially complicated (yeah I know it's easy for a former electronics repair guy to say that, but honestly I've seem much more complex ones than this) - The basic way this works is that the pulses from the sensor are used to switch Q351 on and off. In the absence of the pulse from the sensor, capacitor C352 will charge via the 27K resistor R356. While the tape is running, the constant stream of pulses will be causing Q351 to short the capacitor to ground via the 270 ohm resistor R357, thus preventing the voltage from rising to the point where the relay is activated. When the pulses stop (as at the end of the tape), the pulses will stop and thus the voltage on C352 will be allowed to rise. Once the voltage difference from one side of the diode D353 to the other rises above about 0.6V or so, the diode will conduct and transistor Q352 will turn on, ultimately activating the relay. However, if C352 is leaky to the point where the voltage is draining away faster than it can be charged up, then the threshold voltage will never be reached and thus the auto-stop will never be activated. So if it were me I would start by changing C352. If that fails to fix the issue, then it might be worth checking the transistors themselves, especially given their age now, and also the higher value resistors as old resistors often have a tendency to move in value (usually going higher resistance), but my money would still be on that capacitor as the most likely, followed by a bad transistor if recapping fails to fix it. You should be able to easily test the relay driver transistor Q354 by connecting its base terminal to the B+ line via a 1000 ohm resistor. That should cause the relay to trigger. I'm not sure if you have access to an oscilliscope, but if you have, then it would definitely be worth checking the waveforms at the points marked on the diagram, especially the sawtooth-like waveform in the upper diagramin the region where it is marked "tape run" - if that wave is flat (or significantly flatter than it looks in the diagram), then that would also point to the capacitor C352. (though if Q351 were shorted then this would cause the same symptom, but that would be easy enough to test with a multimeter. If Q351 checks out OK, and changing the capacitor doesn't help, then check the 27K resistor R356. It's unlikely that this has gone open - at worst it might have raised in value, which would still allow the auto-stop to work, though it might take a bit longer to trigger, but it never hurts to check. Good luck Matt - it would be amazing to see this gorgeous machine restored to fully working condition
I wish I could like a comment more than once! It's rare to find someone actually knowledgeable in how this stuff works and actually able to explain it rather than just "recap to fix old broken stuff lol"
Things that I wouldn't miss in RUclips comment sections: -Pointless circular debates and unsupported claims. Things that make it worth still reading comments: - This guy's helpful and knowledgeable input.
Amazing job. The frustration that you felt in this repair is very similar to the frustrations I feel in my job. Getting through a project like this one is a huge accomplishment. You should be proud.
Really enjoyed watching the behind the scenes efforts. It does make me appreciate the time, effort and cost that goes into making each video. I also really admire the workmanship that went into these lovely machines back when I was but a child. And such a beautiful device, so glad you got it working.
Something I learned from a friend which is a technician: when you're getting an oscillating speed on a cassette deck, open it and look directly to the main belt while it's spinning with the deck playing. It must look like it's stopped. No wobbling or swinging around. Many cheap belts (specially here in Brazil, from mid 80s to 2000s) were simply sections cut out from big "hoses", without much care, which worked in a very unbalanced way. You needed to buy many in order to choose the less bad one. I don't know how good are processes or quality control in most chinese manufacturers which makes these nowdays, but I think it's most of the same...
I'm impressed that you didn't give up! I watched a few repair videos made by professionals , but being a beginner, I rarely learnt anything. Thank you for explaining everything you do very well. Thank you for also showing your mistakes.
Matt, I don't comment often, but I want to commend you for your dedication to making videos like this. What a mountain of work it must've been to edit this all together. I really enjoyed watching it! Keep it up and perhaps someone will be able to chime in on the electronics side of this and help you along.
Love love love your channel. You don’t give yourself enough credit! Most people chucked these old machines out as soon as they stopped working, and here you are not only repairing these cool machines, but videotaping yourself doing so, and sharing it with the world. Hell of a job, keep up the great work!
These kind of videos are what i most like of your channel, attempting to repair a mechanical puzzle mixed with your extra-dry sense of humor that hits way after you dropped 'em and with many tries to approach to the same problem I felt identified, usually i have the same behaviour, to stop, step back, trace a new strategy and try again What i have to say? One of the best channels ever
Matt, thank you for inspiring us non-technicians to try and fix our own gear. I’ve fixed my Yamaha CD-Player and Yamaha Cassette Deck myself thanks to watching your various repairs! Thank you!!
Excellent. Thanks for taking the time to edit this together. I think this is exactly the way most mechanically-inclined (but not specifically trained) people go about repairs. Service manuals are very helpful for guidance when you can find them. Otherwise, this is pretty much how I go about a teardown without one as well (until the point when I get stuck and need to ask online for help). Learning from taking various mechanical electronics apart is rewarding, and coming to recognize how everything fits together just by looking at it is part of that skill set that only comes with "doing." Unfortunately, component-level electronic diagnostic training has fallen by the wayside, I think. These days circuit boards are just replaced whole, and made to be. :(
A couple of friends and I were discussing what makes your channel fun to watch versus that of the experts. While the experts are informative and have their funny moments, it's mostly just a brief journey between the beginning of the disassembly and the end. Yours is an adventure from the beginning to the end complete with all the pitfalls and confusion that the rest of us deal with. We are watching a journey we can empathise with and understand, which is why we enjoy your work.
Wire wrapping was very common in the 70s when my Dad was working in the manufacturing industry. He showed me how to use wire wrap tools in the early 80s while saying "You'll probably never need to know this, we don't use them any more." I've used them probably twice in 30 years as a prototype wireman.
Your search for the correct bulb reminded me of a story. In the late 90's, when I was REALLY into car audio, part of my custom amplifier install was to use a large bullet fuse with 1/0 gauge red power wire running from each end and through grommets in the floor of my hatchbacks spare tire cover, between the amplifier cutouts. I stepped down the wire from 1/0 gauge to ~28 gauge wire and connected it to the light in my hatch that turned on when you opened it. Instead of a fuse, in the bullet holder I put a dome light bulb that was roughly the same length. It took me a few different bulbs to find one with the right effect, hence the this video reminding me. It looked as though my main fuse with huge power wires was glowing red hot. I have never seen so many people freak out! As soon as I popped the hatch, there was yelling "it's shorting out!" or "THAT'S NOT RIGHT!". good times
Thank you Mat for putting in all this effort! It t is so good to see that even people like you who are a whole lot more knowledgeable about HiFi systems than the average person is oftentimes just forced to throw stuff at the wall to see what sticks. Watching a trained technician fix faults is all well and good, but I like seeing "mere mortals" (which I don't mean in any offensive way) giving it their best shot - and winning. So my guess is that somebody somewhere on this planet will have a lightbulb moment from this video after tearing their hair out over a so far fruitless attempt at fixing their machine. It is also extremely satisfying to find and successfully fix a fault all by yourself. The way to the solution might not be as the crow flies, but there is a lot to be learned along the way.
My dad made a living repairing all this kind of electronic devices. So when I see this videos bring me back to my childhood happy days. Thanks a lot techmoan for sharing it. Love the channel.
Also, it's mind blowing when you think about the design process behind the construction. A team of engineers had to devise that mechanism, and the tooling to make the parts, etc - amazing skill
Yess another Techmoan vid boy I've missed you. I havent used a tape in over a decade but I've watched everyone of your tape recorder repair vids as they fascinate me. You are a legend for seeing this project through. Only a replacement circuit away from perfection so you should be proud
I am currently in the process of repairing a 1983 sanyo rd r60 cassette deck. I have been having some problems with the belts. After watching this video and taking some notes of your information sources, especially for a service manual, I believe I can get it to live again. Keep up the good work and keep doing these repair videos because you never know whom your video can help someone that is in desperate need.
I appreciate how these episodes of Techmoan (fixing obsolete, but still useful electronics) are like the archaeology of the late industrial age, and how like an archaeological dig there's a lot of guesswork. If it were truly archaeology, though, you'd be able to just say that the broken components had some obscure ritualistic purpose and be done with it
It's made me start to look into investing in an older deck, previously I was nervous that I wouldn't be able to work on it but these videos show you don't need much skill just a lot of patience.
Mat, as I enjoy watching this whole process I am struck once again by your level of patience, experience you've developed by making all these videos, and indefatigable nature to achieve a goal. My knowledge and motivation has been greatly increased by watching you do all these things. Thank you.
Well done, Matt. I admire the way you roll your sleeves up and get stuck in when there is a problem with the equipment you're looking at. A lot of people wouldn't dare.
if your working on this age stuff from japan do not use a philips screw driver you need an jis driver (Japanese Industrial Standard) you will round off far less screw heads
Maybe you are all ready aware of this but those Japanese "Philips" pattern screws usually have a "dot" impressed into the head. This denotes that they are JIS and not Philips or Pozidrive. I only know this by watching a tv programme called "The Re-assembler". In one of the shows, the host James May re-built a Tokai Stratocaster copy and commented that he knew his treasured JIS screwdriver would come in handy one day.
@@JohnDoe-ox5ni I advise to buy a "set" (i.e. differing sizes), not that expensive, BUT keep them away from folks who think they are usual Phillips/Pozidriv screwdrivers, they will abuse and finally damage them.
@@malteseowl I tried searching online for JIS drivers about a year ago from the UK and gave up. It was probably the price for shipping from Japan or the U.S. that was prohibitive. Does anyone know of a supplier in the U.K.?
Even if the process of reparing was quite simple, the whole work of finding out is often the more complex and confusing part, as you demonstrated impressively. Thank you for sharing this project with us and being honest and humble, thats what makes your content so enjoyable to watch!
Lovely video. I've been looking forward to watching the repair of this device. You needn't be so modest about your skill level. I'm no electronics expert, but thought I'd look over the auto-stop diagram in the video out of curiosity. It seems C351, D352, & D351 act as a kind of pump when the tape is turning. Since caps are the most common to fail, would it be a good guess that C351 has failed short circuit? A short fail would mean a constant block to solenoid operation (constant drain on Q352 base voltage). Either that or the C152 cap failed short circuit, never allowing voltage increase at the Q352 base. That's my two pennies' worth...
Matthew you are in the right direction. R351, C351 and Q251 produce short reset pulses to discharge C352 via R357 from the actions of S6. R256, C352 and Q352 form a timer, this timer is constantly reset before it reaches the threshold needed to stop the tape. If C352 is shorted then no tape stop if open tape will stop instantly. Lastly if C350 fails short then again a constant reset state is created.
33:03 It looks like solder on the white cable (in the center of the lefthand edge) is bridging onto the track on it’s right. It looks like too much of a mess for that to be intentional, so I would definately start by fixing that. NB: like Matthew, I’m no expert (I can’t even read wiring diagrams very well), so I could be totally wrong! - Should probably spend more time watching @bigclivedotcom
@@timballam3675 He obviously doesn't have an oscilloscope. He shows how he verified there is an alternating voltage while playing, and invariant when stopped - which is a rough test to show the sensor is working. At this point, he can do basic tests on components in the circuit - though the fact they are in-circuit makes it more difficult.
This one brought back uncomfortable memories of when I tore into my own cassette deck to find out that, as you said, the thing seems to be built around the drive belts, and the only way to access same is through disassembly of some pretty complicated machinery. I suppose I ought to try it again, since my tape collection is silent until I figure out a fix or simply replace the deck, which I really don’t want to do. I found it interesting to compare devices such as this cassette deck with modern digital music players, which frequently have no moving parts whatsoever.
This video was great! It's so nice to see humanized repair experiences instead of some magical chap repairing the entire thing with perfect knowledge from the get-go.
Its so cool and awesome to know there are still people out there that still have a love of these once proud machines... now just dinosaurs and relics of yesteryear if it weren't for people like you.. this machine would have met a sad end... please keep repairing these machines... and keep the repair of machines of this nature going... there are a lot of people out there that still use things like this and many that may need repairs so they may continue to work for many more years to come...
On the Autostop circuit board. The pulsing can be used to “pump” up a voltage level so if the pulsing stops that voltage drains out and that voltage level via a transistor then drives the solenoid. Such pulse controlled circuits are often tuned to the frequency of the pulsing and the storage of that voltage and the power of the pulse to activate the solenoid all likely have capacitors involved. And we know the electrolytic capacitors drift and fail with many years if age under them as the electrolyte dries out. So I’d take a crack at just replacing those electrolytic capacitors in the Autostop boards with the same rated new ones. Make sure you get the + and - correct on the capacities to match where the old ones were.
I have personally experienced the connections on an IC that the manufacturer used silver (turned black) to the point it tarnished between the leads on the IC ... the symptom was noise (loud and soft hissing) in the playback it was the preamp IC ... desoldered cleaned the tarnish of the IC legs and soldered back in place and it was as it was as new (as quite as the equipment of its age anyway it wasn't a premium quality deck but beats most new machines that could be purchased today ... anyway it may not ALWAYS be a bad component in such circuits ... I have saw dark component leads on a wide variety of components ... I'm strongly thinking it is because of silver in the blend of the component leads
My guess is that the electrolytic capacitor that charges up to provide the current for the solenoid has dried up. The semiconductors are less likely to fail. The power transistor that dumps the current into the solenoid has a very low duty cycle and the diode that proctects against the inductive spike of the solenoid, so long so it has a sufficient voltage rating, is also likely to be fine.
No doubt someone discussed this below, but the circuit isn't a capacitor "pump". The pulses repeatedly discharge a capacitor that would otherwise only slowly allow the control voltage to rise. If the timing capacitor weakens (loses capacity), the control voltage rises faster and would auto-stop even when it shouldn't. If the pulse coupling capacitor weakens, the heartbeat pulses don't pass out of the first stage and auto-stop would similarly be quickly triggered. My guess is that the auto-stop electronics aren't involved here, but the switches (in the upper right of the schematic) aren't making good contact and the circuit is never powered. Or perhaps only the solenoid isn't getting power.
I adore those cassette control levers, the feel when you press them is one of the best I’ve ever experienced in the hi-fi world. I used to have a Pioneer CT-F2121 cassette deck, it looked almost same as this one without it's nice watch. I was very sad when it was stolen.
Another great Saturday morning treat, thank you Mat. Looking at the circuit, I am going to suggest you need to do a capacitor replacement activity to return the transistor based auto stop back to functionality. Should be a relatively simple job of ordering the capacitors (values on the side of each) observing the polarity and soldering the new ones back in place. Be brave and take your time and you will have success!
Or it could be the transistor (is it a x-sistor or a voltage regulator). Both should be easier enough to test but as Nic stated it could be a tired cap.
I'm in the midst of fixing a broken Yamaha K-300 deck from 82. New belts have arrived but I haven't motivated myself to open it back up until I watched this video. Thanks!
I really love how honest this guy is. One of the best channels for this sort of stuff and I'm looking fowards to seeing more videos about these sort of machines!
Great video, thanks. The autostop is issue could be a transistor, but it's always best to check with a multimeter if the board is getting the correct supply voltages first. You can get small component testers for something like $10, that will allow you to desolder and test individual components until you find a faulty one. That is probably the easiest way to repair electronics without being able read the schematic. Other than that, a small cheap oscilloscope can be very useful in fault finding.
I enjoyed sharing your ups and downs along the way. So many flashbacks of trying to repair my dad’s cassette with incompatible belts that just don’t seem to work consistently many years ago.
It turned out that was a short. I ended up doing the same thing again and that’s how I realised what it was. Auto-stop didn’t work from the beginning, I tested it before I opened up the case.
@@Techmoan Speaking as a one time electronics repair person that auto stop mechanism is from a 70's machine. That means it will all be discrete components and should be fairly easy to repair. If I were looking at it the very first thing I would do is check all the soldering and look for dry joints. The second today would be the capacitors and the third would be to look at the transistors. Another common source of trouble might be a bad joint in a wire, usually between the wire itself and one of the connectors.
@Mr Guru Not quite the words I'd choose, but solid advice. If you're a more visual learner you could use a circuit simulator to show you the expected voltages at every point in the circuit, and compare that - for audio frequency signals even a simple pocket oscilloscope (less than 30 quid off ebay) will let you compare expected waveforms.
@Mr Guru I agree that they're not needed a lot of the time, but, as you can see in this example, service manuals often include diagrams of what a signal should look like at selected points in the circuit. While 'knowing how to use it' varies depending on what you're using it for, even without knowing the full details of the workings of a circuit, a keen amateur, or a trained diagnostic repairman, can follow a block diagram and isolate the fault to a particular section by simply finding the point in the circuit the scope doesn't match the picture.
Hi there, I love your videos. I am blind and the way you describe things is just great. Keep it coming. Love all this vintage tech that you’re showing. Takes me back.
Really nice video, Matt! I love the internal design of these 60s/70s Japanese electronics, they always show there was a lot of thought about maintenance from the start of a project, with foldable circuit boards and enough cable length to get stuff out of the way. I just wish they had less solder and more plugs and sockets. I ran into the same problem of mysterious wowing, and in a very similar frequency to yours, a few weeks ago even after replacing every belt and cleaning every idler wheel I could find on my Sony TC-150. However, mine didn't miraculously sort itself out. I'm guessing it might be an old capacitor down on the power regulation circuitry. It only really bothers me when playing tapes recorded on the same machine, as the fluctuations in playback speed are added to those from the recording.
I rarely comment on videos but I must say I just watched a half hour video about repairing a cassette deck and didn't get bored or consider clicking off even once! Thanks man great video
There was a vinyl shortage in the 70s, and LP record quality went way down because of re-ground vinyl, un-sold records being returned and recycled for pressing new records with. I have a copy of Quadrophenia by the Who with bits of rusty metal imbedded in the grooves!
Interesting theory! My PhD supervisor recounted how he and his colleagues worked on plastic substitutes in the 70s for this reason (which would have been environmentally sustainable, too) only for the funding to instantly dry up when oil prices came down again.
@@BlameThande , Henry Ford built an experimental car body entirely out of soy-based plastic. The biggest drawback that I can surmise is that mice and squirrels might find it particularly interesting to gnaw on, as they often did with some antique radios where the wiring insulation was soy-based.
24:37 Wire-wrap was pretty common back then. I remember my dad even had a tool that would do it automatically (you pulled a trigger and it would spin the wire around the post). Antiquated stuff, but neat to see nowadays.
Correctly done it's actually far more reliable than soldering. I have worked in nuclear power plants and all connections in the safety control systems logic were wire wrap.
@@denislostinlondon199 I dont think i have ever seen wire wrap with the insulation in place, but i have never used the method myself, i started working in electronics in the 80´s.
Come on Techmoan, really no need to beat yourself up. You did a fantastic job fixing this unit. I know there are viewers that are critics of everything, but what you've demonstrated is that with a bit of patience and drive anyone can tackle something like this. Regards,
"Okay now, this was another mistake. I shouldn't have done this- it made things worse." I need to make a little button on my desk that plays this clip for when I fail to fix things.
Wow...I am so blown away by your tenacity to do things the right way and to finish the job to the end! I also admire how you video the good with the bad..You are definitely my go-to guy when it comes to fixing stereos and other components. Thanks so much!🇨🇦👍😉
All right, you won me over! :-D Been watching for years, and I figured your efforts deserve a little more than just the odd ‘Like’ now and then, so I got off my arse and joined the Patreon. Count me as well entertained (oh, and that little Polaroid CUBE+ cam still does the job) :-)
Whatever you do, do not feel bad about your repair and your ability. You saved another piece of equipment and you learnt. You enhanced your knowledge. It doesn't matter if other people knew better. Plus, you have probably got more feeling for the cassette recorder now. I recently repaired my 5yo amp. Although I was upset it broke, looking back I enjoyed it as it worked my brain and occupied me during lockdown. And you know what, instead of moaning about my amp for breaking, I actually find myself liking it more because I got tok now it intimately and deeply. Pat yourself on the back!
Really enjoyed this video-you have the patience of a saint-I salute you for getting it working again.Just a tip-sometimes a squirt of contact cleaner or deoxit in the motor speed control hole can fix a wow and flutter issue due to the speed control screw inside the motor oxidising-its just a variable resistor
Mike Eastridge yes agreed but I wasn’t recommending spinning it more than a couple of times back and forth with contact cleaner-which also acts as a lubricant-so the chances of damaging the pot are virtually zero-I’m an electronics engineer so I’d like to think I know what I’m talking about 😀😀😀👍👍👍 You could also leave well alone and put up with the horrendous wow and flutter 🙁🙁🙁
I guess I'm weird cause I said "ohh boy a 30 min one means it will be good....". To me he's pulling off small miracles by bringing these old gems back to life and I hope they keep coming.
The most important skill to have when working on this type of thing is patience. Matt has that covered. Loved the video. I've watched it several times.
Thank you for the great tip - sticky taping the screws to a labelled piece of paper - I wish I'd thought of that last week, when I took apart a synthesiser! hahahaaa Great vid Mat. :)
I draw a rough outline of the part I'm disassembling and its screw holes on a piece of paper and push the screws through the diagram at the corresponding point I removed them - that way when I reassemble the device I can just follow the diagrams backwards.
My mate taught me to get a bit of thick cardboard and screw the screws into the cardboard. Done properly they won't go anywhere if it gets moved or knocked, and you can screw them in in the same pattern as they are on the device.
Marvellous viewing. When people say ‘ blimey - that was a dear do back in the day ‘ this particular example is self explanatory, highlighting the complexity and labour intensive building and content of electrical/mechanical consumer products and the cost associated of getting the thing past final test and in to somebody’s home. Having spent a lifetime in the industry from the dawn of colour TV to the present digital age and the rapid leaps in technology which most nontechnical people just take for granted can you imagine what the next 25 years hold for us all bearing in mind the stratosphoric advances in recent years - mind boggling. Wonderful content by the way Matt !
I very much enjoyed this video. It's a story, and has progression along the way of how you worked things out, changed your mind on things, ordered parts. It's not an experience you could've thrown together in an afternoon.
Usually, for me "English" English is a listening nightmare, but Techmoan accent and pronunciation are quite nice and understandable, great! I enjoy it very much
He has a Southern accent which is what English people on TV are usually portrayed with, so it's very easy to understand. Techmoan speaks very clearly any way. I'm English but can't quite pick out exactly where he's from.
When I was growing up I spent all my time dismantling things and experimenting with electronics. Over the years I've lost a lot of that confidence, but videos such as this really help to remind me what is possible with a bit of patience, care and attention. Thanks Matt.
Just because you don't have the in-depth knowledge to fix the auto stop, doesn't mean you don't know enough! We all have to start somewhere in our skills, and you took on this project and did learn alot! I am sure your other skills are well established and you have the knowledge in them. The thing that impressed me was that you did try, and learned alot along the way, even without a service manual! Congratulations on your repair!
I feel like the guy responcible for that notch was on his death bed and he watched this video. After he appreciated his work the notch guy was able to die in peace.
Really like the look of this. It’s got so many classic retro features. Love that you push the cassette deep into the unit at an angle, then the 3D effect once it is housed and lit up. Tip to anyone restoring 70’s /80s separates - if replacing light bulbs-be sure to use yellow-effect ones. Bright, bluey or intense ones totally spoil the look. Quite addicted to your videos now!
Discovered this channel a few weeks ago. I love seeing you grow and learn over the episodes. My very first midi tower was a Pioneer.Actually bought it for an apple and an egg. This is a saying in Dutch. When something is bought very cheap you bought it for "an apple and an egg" and an electronica retailer, wen opening a shop in my town in the early 70's, would "sell" a piece of equipment of your choice to the first 10 customers for an actual apple and egg. I was customer #2 and choose that Pioneer tower. When I later in life went for components I usually choose either Philips (National pride obviously) or for some strange reason Technics. (great brand but mostly mid range)
really glad you got it working. There's nothing quite like finishing restoring something like this - thank you for documenting it, and well done for giving it a new lease on life. I'm looking forward to whenever you do fix that last issue on the circuit board, I'm sure some genius in the comments already has it sussed.
Your issue with fixing things is where I stand with cars. I Know most of what goes together, but when people, especially in the Ford Capri community, do a task easily, i struggle. Learning these things take time and that's where the problem is in a lot of our busy lives. Really pleased you were able to get the time to pull it apart and get it working decently. Full pat on the back in my opinion. That wow and flutter, jeez!
@@kkuukkoo2 only problem is getting obsolete parts! Probably not "hard" to reverse engineer and find suitable alternatives if they're saturating, which would seem likely in this scenario, but if they're being used in their linear regions it gets more annoying.
Everyone that repairs stuff for a living, myself included - all had to start from somewhere. I’ve always found the best way to learn about fixing anything is to just not be afraid and have a go. (Obviously within reason) what you did in this video, making a thousand mistakes and then working it out in the end to great satisfaction is familiar to many of us.
I believe you to have such a patient skill ... I love that you can show the level of your skill ...and also your limit ... I am always trying to improve on my limited repair skill and watching your video gives me a new found hope ...thank you ... Please continue to bring color to my world ... Raul ...
The correct way of removing a screw with a damaged head is...... any way that gets it out without damaging the product.
Yeah. the scariest I ever had to deal with was an exhaust manifold stud that broke off in an aluminum cylinder head. I was able to drill into the stud itself and then use an extractor tool on the end of a power drill to remove it, but that was about the most stressful damaged fastener I've had to contend with.
Honorable mention was a valve rocker shaft, but the fastener was brand new and so was the head, so when it broke I was able to extract it by just turning it with a pick.
First try squeezing a rubber band (or an old flat belt...) on the screw with the screwdriver. It generates more grip.
Which usually (in my case anyway) includes vast quantities of foul language, skinned knuckles, and an unusable part when finished ;-)
@@DumahBrazorf My dad has screwdrivers whith a section to put a wrench on them. Best way to break of the head I know.
@@n7565j There is a natural sequence which starts with swearing, then WD40 and swearing and so on.
The difference between you and an expert is that the expert edits out all the mistakes he made.
Simon Petrikov the expert also makes more critical mistakes because they are too lax where they shouldn’t be
What he lacks in knowledge he makes up for tenfold in perseverance. Love this channel.
There's an old saying that states that in order to look like a genius, you only have to guess right three times in a row :)
Basically the video version of - A grinder and paint make me the welder I ain't.
Expert
Ex - “Previously”
Spurt - “A drip under pressure”
I laughed heartily at "if you didn't like it, please don't let me know".
Really fun video. I love deep dives into electronics and repairs.
The anti-Simon Whistler. In Simon's Business Blaze channel, one of his catchphrases is "SMASH THAT DISLIKE BUTTON!"
Patreon Alert
LOL that got me as well!
Reminds me of Jeremy Clarkson on Top Gear telling people, if I recall correctly, that if they did not like something, then please, do feel free to keep it to yourself.
@@tgheretford if people did that half the internet sites would vanish overnight! 😁
"I could have just overdubbed the audio, and no one would have been the wiser... BUT THAT'S NOT GENUINE!" Right on dude! That's the way these type of videos should be done!
Saturday mornings with Techmoan is the adult equivalence of Saturday morning cartoons. That episode was brilliant. loved it.
Best description I've ever come across :)
Some engineer in Japan in their 70s or 80s, if they were to view this would be extremely happy with their work and your love and care over something so constructed. Thank you for your great videos and narration. Please, please keep such great content and preservation alive.
You didn't want to know if I didn't enjoy this video. OK. I have to therefore let you know that I LOVED this video. Captivating from start to finish.
I honestly thought this vid would be boring as all get out... i was very wrong.. great vid
TexasNight It would be boring without the right presenter. Matt’s a natural at this.
This video made me take another crack at fixing my first record player! I'd given up on the thing and replaced it with a lovely German turntable from the '80s. Now my first player is not only working, but I've restored it back to it's original home in my booth. Thanks for the indirect inspiration, my dude!
That was maybe my favorite techmoan video ever. Excellent work, Matt.
When he got to the point where it looked like the whole mech would have to come apart just to replace that belt, I was like... ok I would seal this thing up and go on to something else.
I am actually glad, that he has no repair shop near by. This surely was a lot of work, but it is far, far more interesting than "I paid 200£ to get it all fixed"
Your favorite Techmoan video _so far._
That was excellent video ,plus i like whole deck was metal than plastic
How tf did u comment 1 week ago?
I’ve been fiddling with repairing a ct-f2121. It’s astounding how fine the tolerances are in the belts and tensions in these mechanisms. Good call on the rubber o rings, I did the same. Well done for persevering!
Tech Moan : I'm not qualified and I dont really know what I'm doing.
Does all research, takes down, diagnoses, repairs, knows all the names and other stuff I wouldnt even think of.
90% of any job is organisation.
@@anonUK he really understands more than he credits himself for mostly due to being largely self taught. He definitely understands mechanics of fly wheels and especially rubber belts and rings.
I think he's comparing himself to people like Neil from "reto man cave" who regularly restore nonfunctional hardware.
What's interesting to me is that even with all he's demonstrably capable of, he still has the bits (e.g. at 33:06) where he's got the belief that he's at his limits. Which is maybe just accurate, as far as current knowledge... but I'm sure he could learn more, and hope he might. :)
Frank Barone The old tube stuff is what gets me going. Current projects are a 1926 tabletop tube shortwave radio (“farm battery” type, so I need to build a power supply, as well as an output converter since it’s made for old-style speakers) and a 1947 New Zealand tabletop shortwave radio. I chose big projects there, considering how much work is to be done to make them functional. But tubes are always so much fun.
I don’t _really_ know what I’m doing, like Matt, but somehow figure it out. If you can solder and read a schematic, you can often figure it out as you go along. It also helps that I’ve collected a series of old (as far back as 1910 or so) electronics, electrical & radio repair books with a ton of stuff on tunes. Amazing resources if you can find them that aren’t online or digitized anywhere. A lot of lost knowledge.
Your perseverance is really inspiring. You demonstrate a simple method for attacking a problem: have at it until you hit a wall, then step back for a while and take a breath, then dive in again. Like Einstein said: "It's not that I'm so smart. It's just that I stay with problems longer."
I think it was a combination of his way above average IQ and determination and not an either/or thing. But what do I know, I'm no Einstein. Lol
I like how you show all the wrong turns along the way. It's like an exploration of a puzzle and makes the solution all the more enjoyable.
👍🏼👍🏼👍🏼
Hell ya.
When I saw the length of this video i thought 'oef, this too long, i could be seeing a lot of other interesting videos in the same time'. But i gave it a try and, as always, i found this again a very entertaining video. The way you explain your struggles, keep your honesty and not boast about your accomplishments make your videos very genuine en make you a very likable guy. Thank you very much for this half hour of technical meditation.
Radio tuner and the Amp but I left the tape player behind then some one else bought it.
Fastest way to spend a half an hour: watch techmoan video.
Exactly I used to watch entertaining videos but now I only watch educational videos
Hey Matt;
I've never worked on this particular deck, but I've seen many others from the late 70s and early 80s with electronic auto-stop faults and they've generally been down to bad electrolytic capacitors in the auto-stop circuit. On the diagram you showed in the video at around 32:40 I would say that the prime suspect would be C352 (100uF/35V). Once this component starts leaking, it will be unable to fully charge, possibly to the point where the voltage across D353 is insufficient to trigger switch on transistor Q352. This could prevent the auto-stop from engaging.
The auto-stop circuit is not especially complicated (yeah I know it's easy for a former electronics repair guy to say that, but honestly I've seem much more complex ones than this) - The basic way this works is that the pulses from the sensor are used to switch Q351 on and off. In the absence of the pulse from the sensor, capacitor C352 will charge via the 27K resistor R356. While the tape is running, the constant stream of pulses will be causing Q351 to short the capacitor to ground via the 270 ohm resistor R357, thus preventing the voltage from rising to the point where the relay is activated. When the pulses stop (as at the end of the tape), the pulses will stop and thus the voltage on C352 will be allowed to rise. Once the voltage difference from one side of the diode D353 to the other rises above about 0.6V or so, the diode will conduct and transistor Q352 will turn on, ultimately activating the relay.
However, if C352 is leaky to the point where the voltage is draining away faster than it can be charged up, then the threshold voltage will never be reached and thus the auto-stop will never be activated.
So if it were me I would start by changing C352. If that fails to fix the issue, then it might be worth checking the transistors themselves, especially given their age now, and also the higher value resistors as old resistors often have a tendency to move in value (usually going higher resistance), but my money would still be on that capacitor as the most likely, followed by a bad transistor if recapping fails to fix it.
You should be able to easily test the relay driver transistor Q354 by connecting its base terminal to the B+ line via a 1000 ohm resistor. That should cause the relay to trigger.
I'm not sure if you have access to an oscilliscope, but if you have, then it would definitely be worth checking the waveforms at the points marked on the diagram, especially the sawtooth-like waveform in the upper diagramin the region where it is marked "tape run" - if that wave is flat (or significantly flatter than it looks in the diagram), then that would also point to the capacitor C352. (though if Q351 were shorted then this would cause the same symptom, but that would be easy enough to test with a multimeter. If Q351 checks out OK, and changing the capacitor doesn't help, then check the 27K resistor R356. It's unlikely that this has gone open - at worst it might have raised in value, which would still allow the auto-stop to work, though it might take a bit longer to trigger, but it never hurts to check.
Good luck Matt - it would be amazing to see this gorgeous machine restored to fully working condition
Beat me to it, was gonna post this myself
I wish I could like a comment more than once! It's rare to find someone actually knowledgeable in how this stuff works and actually able to explain it rather than just "recap to fix old broken stuff lol"
do you repair electronic equipement like parametric equalizers Aphex 109 and tape deck with CD Tascam ?
Things that I wouldn't miss in RUclips comment sections:
-Pointless circular debates and
unsupported claims.
Things that make it worth still reading comments:
- This guy's helpful and knowledgeable input.
Very nice troubleshoot for this circuit. I was thinking along the same lines due to age and design. maybe TM will try to tackle the fix.
Amazing job. The frustration that you felt in this repair is very similar to the frustrations I feel in my job. Getting through a project like this one is a huge accomplishment. You should be proud.
Really enjoyed watching the behind the scenes efforts. It does make me appreciate the time, effort and cost that goes into making each video. I also really admire the workmanship that went into these lovely machines back when I was but a child. And such a beautiful device, so glad you got it working.
Something I learned from a friend which is a technician: when you're getting an oscillating speed on a cassette deck, open it and look directly to the main belt while it's spinning with the deck playing. It must look like it's stopped. No wobbling or swinging around. Many cheap belts (specially here in Brazil, from mid 80s to 2000s) were simply sections cut out from big "hoses", without much care, which worked in a very unbalanced way. You needed to buy many in order to choose the less bad one. I don't know how good are processes or quality control in most chinese manufacturers which makes these nowdays, but I think it's most of the same...
Waking up to TechMoan episodes each Saturday has been like waiting for Saturday morning cartoons as a kid.
I'm having dinner! Great to watch
I'm impressed that you didn't give up! I watched a few repair videos made by professionals , but being a beginner, I rarely learnt anything. Thank you for explaining everything you do very well. Thank you for also showing your mistakes.
Matt, I don't comment often, but I want to commend you for your dedication to making videos like this. What a mountain of work it must've been to edit this all together. I really enjoyed watching it! Keep it up and perhaps someone will be able to chime in on the electronics side of this and help you along.
Love love love your channel. You don’t give yourself enough credit! Most people chucked these old machines out as soon as they stopped working, and here you are not only repairing these cool machines, but videotaping yourself doing so, and sharing it with the world. Hell of a job, keep up the great work!
I'm happy to say that I thoroughly enjoyed watching the video.
Ditto
I know just about nothing about electronics, but this was really satisfying to watch. It actually inspired me to learn more about them!
These kind of videos are what i most like of your channel, attempting to repair a mechanical puzzle mixed with your extra-dry sense of humor that hits way after you dropped 'em and with many tries to approach to the same problem
I felt identified, usually i have the same behaviour, to stop, step back, trace a new strategy and try again
What i have to say? One of the best channels ever
Matt, thank you for inspiring us non-technicians to try and fix our own gear. I’ve fixed my Yamaha CD-Player and Yamaha Cassette Deck myself thanks to watching your various repairs! Thank you!!
Excellent. Thanks for taking the time to edit this together. I think this is exactly the way most mechanically-inclined (but not specifically trained) people go about repairs. Service manuals are very helpful for guidance when you can find them. Otherwise, this is pretty much how I go about a teardown without one as well (until the point when I get stuck and need to ask online for help). Learning from taking various mechanical electronics apart is rewarding, and coming to recognize how everything fits together just by looking at it is part of that skill set that only comes with "doing." Unfortunately, component-level electronic diagnostic training has fallen by the wayside, I think. These days circuit boards are just replaced whole, and made to be. :(
A couple of friends and I were discussing what makes your channel fun to watch versus that of the experts.
While the experts are informative and have their funny moments, it's mostly just a brief journey between the beginning of the disassembly and the end.
Yours is an adventure from the beginning to the end complete with all the pitfalls and confusion that the rest of us deal with. We are watching a journey we can empathise with and understand, which is why we enjoy your work.
Wire wrapping was very common in the 70s when my Dad was working in the manufacturing industry. He showed me how to use wire wrap tools in the early 80s while saying "You'll probably never need to know this, we don't use them any more." I've used them probably twice in 30 years as a prototype wireman.
Your search for the correct bulb reminded me of a story.
In the late 90's, when I was REALLY into car audio, part of my custom amplifier install was to use a large bullet fuse with 1/0 gauge red power wire running from each end and through grommets in the floor of my hatchbacks spare tire cover, between the amplifier cutouts. I stepped down the wire from 1/0 gauge to ~28 gauge wire and connected it to the light in my hatch that turned on when you opened it. Instead of a fuse, in the bullet holder I put a dome light bulb that was roughly the same length. It took me a few different bulbs to find one with the right effect, hence the this video reminding me.
It looked as though my main fuse with huge power wires was glowing red hot.
I have never seen so many people freak out! As soon as I popped the hatch, there was yelling "it's shorting out!" or "THAT'S NOT RIGHT!".
good times
Thank you Mat for putting in all this effort!
It t is so good to see that even people like you who are a whole lot more knowledgeable about HiFi systems than the average person is oftentimes just forced to throw stuff at the wall to see what sticks. Watching a trained technician fix faults is all well and good, but I like seeing "mere mortals" (which I don't mean in any offensive way) giving it their best shot - and winning. So my guess is that somebody somewhere on this planet will have a lightbulb moment from this video after tearing their hair out over a so far fruitless attempt at fixing their machine.
It is also extremely satisfying to find and successfully fix a fault all by yourself. The way to the solution might not be as the crow flies, but there is a lot to be learned along the way.
My dad made a living repairing all this kind of electronic devices. So when I see this videos bring me back to my childhood happy days. Thanks a lot techmoan for sharing it. Love the channel.
Also, it's mind blowing when you think about the design process behind the construction. A team of engineers had to devise that mechanism, and the tooling to make the parts, etc - amazing skill
Yess another Techmoan vid boy I've missed you. I havent used a tape in over a decade but I've watched everyone of your tape recorder repair vids as they fascinate me. You are a legend for seeing this project through. Only a replacement circuit away from perfection so you should be proud
I love Saturdays, especially when they start with Techmoan
It's become part of my Saturday morning routine.
@@spugintrntl Same, I make a pot of coffee and then immediately check for the new video.
Techmoan is such an awesome RUclipsr
I am currently in the process of repairing a 1983 sanyo rd r60 cassette deck. I have been having some problems with the belts. After watching this video and taking some notes of your information sources, especially for a service manual, I believe I can get it to live again. Keep up the good work and keep doing these repair videos because you never know whom your video can help someone that is in desperate need.
I appreciate how these episodes of Techmoan (fixing obsolete, but still useful electronics) are like the archaeology of the late industrial age, and how like an archaeological dig there's a lot of guesswork.
If it were truly archaeology, though, you'd be able to just say that the broken components had some obscure ritualistic purpose and be done with it
It's made me start to look into investing in an older deck, previously I was nervous that I wouldn't be able to work on it but these videos show you don't need much skill just a lot of patience.
@@Zerbey it's true but patience and skill often run together one assists the other.
Techmoan, I really do appreciate your honesty, and your determination. Absolutely brilliant.
Mat, as I enjoy watching this whole process I am struck once again by your level of patience, experience you've developed by making all these videos, and indefatigable nature to achieve a goal. My knowledge and motivation has been greatly increased by watching you do all these things. Thank you.
Well done, Matt. I admire the way you roll your sleeves up and get stuck in when there is a problem with the equipment you're looking at. A lot of people wouldn't dare.
if your working on this age stuff from japan do not use a philips screw driver you need an jis driver (Japanese Industrial Standard) you will round off far less screw heads
Maybe you are all ready aware of this but those Japanese "Philips" pattern screws usually have a "dot" impressed into the head. This denotes that they are JIS and not Philips or Pozidrive. I only know this by watching a tv programme called "The Re-assembler". In one of the shows, the host James May re-built a Tokai Stratocaster copy and commented that he knew his treasured JIS screwdriver would come in handy one day.
@@markmiwurdz202 every day is a school day :-) Cheers for sharing that little gem of information.
@Justin if I learn nothing else today I now know the Japanese love their jis precision screws for fixing their equipment. Cheers I might get one.
@@JohnDoe-ox5ni I advise to buy a "set" (i.e. differing sizes), not that expensive, BUT keep them away from folks who think they are usual Phillips/Pozidriv screwdrivers, they will abuse and finally damage them.
@@malteseowl I tried searching online for JIS drivers about a year ago from the UK and gave up. It was probably the price for shipping from Japan or the U.S. that was prohibitive. Does anyone know of a supplier in the U.K.?
Even if the process of reparing was quite simple, the whole work of finding out is often the more complex and confusing part, as you demonstrated impressively. Thank you for sharing this project with us and being honest and humble, thats what makes your content so enjoyable to watch!
Lovely video. I've been looking forward to watching the repair of this device. You needn't be so modest about your skill level.
I'm no electronics expert, but thought I'd look over the auto-stop diagram in the video out of curiosity. It seems C351, D352, & D351 act as a kind of pump when the tape is turning. Since caps are the most common to fail, would it be a good guess that C351 has failed short circuit? A short fail would mean a constant block to solenoid operation (constant drain on Q352 base voltage).
Either that or the C152 cap failed short circuit, never allowing voltage increase at the Q352 base.
That's my two pennies' worth...
Matthew you are in the right direction. R351, C351 and Q251 produce short reset pulses to discharge C352 via R357 from the actions of S6. R256, C352 and Q352 form a timer, this timer is constantly reset before it reaches the threshold needed to stop the tape. If C352 is shorted then no tape stop if open tape will stop instantly. Lastly if C350 fails short then again a constant reset state is created.
It's possible those 40+ year old electrolytics have simply dried out and the unit hasn't been in use enough for any kind of bulge.
33:03
It looks like solder on the white cable (in the center of the lefthand edge) is bridging onto the track on it’s right. It looks like too much of a mess for that to be intentional, so I would definately start by fixing that.
NB: like Matthew, I’m no expert (I can’t even read wiring diagrams very well), so I could be totally wrong! - Should probably spend more time watching @bigclivedotcom
First things to do is use a oscilloscope to verify the two signals are present as per the schematic....
@@timballam3675 He obviously doesn't have an oscilloscope. He shows how he verified there is an alternating voltage while playing, and invariant when stopped - which is a rough test to show the sensor is working. At this point, he can do basic tests on components in the circuit - though the fact they are in-circuit makes it more difficult.
This one brought back uncomfortable memories of when I tore into my own cassette deck to find out that, as you said, the thing seems to be built around the drive belts, and the only way to access same is through disassembly of some pretty complicated machinery. I suppose I ought to try it again, since my tape collection is silent until I figure out a fix or simply replace the deck, which I really don’t want to do. I found it interesting to compare devices such as this cassette deck with modern digital music players, which frequently have no moving parts whatsoever.
This video was great! It's so nice to see humanized repair experiences instead of some magical chap repairing the entire thing with perfect knowledge from the get-go.
Completely agree. Makes me feel better about my repair efforts...
Its so cool and awesome to know there are still people out there that still have a love of these once proud machines... now just dinosaurs and relics of yesteryear if it weren't for people like you.. this machine would have met a sad end... please keep repairing these machines... and keep the repair of machines of this nature going... there are a lot of people out there that still use things like this and many that may need repairs so they may continue to work for many more years to come...
On the Autostop circuit board.
The pulsing can be used to “pump” up a voltage level so if the pulsing stops that voltage drains out and that voltage level via a transistor then drives the solenoid. Such pulse controlled circuits are often tuned to the frequency of the pulsing and the storage of that voltage and the power of the pulse to activate the solenoid all likely have capacitors involved.
And we know the electrolytic capacitors drift and fail with many years if age under them as the electrolyte dries out.
So I’d take a crack at just replacing those electrolytic capacitors in the Autostop boards with the same rated new ones. Make sure you get the + and - correct on the capacities to match where the old ones were.
My guess would be that one of the protection diodes has failed, probably taking the C1419 transistor with it.
I have personally experienced the connections on an IC that the manufacturer used silver (turned black) to the point it tarnished between the leads on the IC ... the symptom was noise (loud and soft hissing) in the playback it was the preamp IC ... desoldered cleaned the tarnish of the IC legs and soldered back in place and it was as it was as new (as quite as the equipment of its age anyway it wasn't a premium quality deck but beats most new machines that could be purchased today ... anyway it may not ALWAYS be a bad component in such circuits ... I have saw dark component leads on a wide variety of components ... I'm strongly thinking it is because of silver in the blend of the component leads
My guess is that the electrolytic capacitor that charges up to provide the current for the solenoid has dried up. The semiconductors are less likely to fail. The power transistor that dumps the current into the solenoid has a very low duty cycle and the diode that proctects against the inductive spike of the solenoid, so long so it has a sufficient voltage rating, is also likely to be fine.
No doubt someone discussed this below, but the circuit isn't a capacitor "pump".
The pulses repeatedly discharge a capacitor that would otherwise only slowly allow the control voltage to rise.
If the timing capacitor weakens (loses capacity), the control voltage rises faster and would auto-stop even when it shouldn't.
If the pulse coupling capacitor weakens, the heartbeat pulses don't pass out of the first stage and auto-stop would similarly be quickly triggered.
My guess is that the auto-stop electronics aren't involved here, but the switches (in the upper right of the schematic) aren't making good contact and the circuit is never powered. Or perhaps only the solenoid isn't getting power.
@@1djbecker pretty sure this is what happened to my dad’s Marantz tape deck. Auto stop would constantly kick in. I think he even still has it.
I adore those cassette control levers, the feel when you press them is one of the best I’ve ever experienced in the hi-fi world.
I used to have a Pioneer CT-F2121 cassette deck, it looked almost same as this one without it's nice watch. I was very sad when it was stolen.
Your repair videos give me more confidence in my own repairs. Right now, I'm working on a Teac 3300-11 two track stereo reel to reel deck.
How do you make everything so interesting? It's like you have a super-power! Brilliant, as always!
Another great Saturday morning treat, thank you Mat.
Looking at the circuit, I am going to suggest you need to do a capacitor replacement activity to return the transistor based auto stop back to functionality. Should be a relatively simple job of ordering the capacitors (values on the side of each) observing the polarity and soldering the new ones back in place. Be brave and take your time and you will have success!
Or it could be the transistor (is it a x-sistor or a voltage regulator). Both should be easier enough to test but as Nic stated it could be a tired cap.
I'm in the midst of fixing a broken Yamaha K-300 deck from 82. New belts have arrived but I haven't motivated myself to open it back up until I watched this video. Thanks!
I really love how honest this guy is. One of the best channels for this sort of stuff and I'm looking fowards to seeing more videos about these sort of machines!
Great video, thanks. The autostop is issue could be a transistor, but it's always best to check with a multimeter if the board is getting the correct supply voltages first. You can get small component testers for something like $10, that will allow you to desolder and test individual components until you find a faulty one. That is probably the easiest way to repair electronics without being able read the schematic. Other than that, a small cheap oscilloscope can be very useful in fault finding.
I wasn't expecting half of that... Perhaps one of the best episodes you've put out so far!
Thank you!
I enjoyed sharing your ups and downs along the way. So many flashbacks of trying to repair my dad’s cassette with incompatible belts that just don’t seem to work consistently many years ago.
I bet that "pop" sound you heard at one point was something blowing out that made the auto-stop work.
It turned out that was a short. I ended up doing the same thing again and that’s how I realised what it was. Auto-stop didn’t work from the beginning, I tested it before I opened up the case.
@@Techmoan Speaking as a one time electronics repair person that auto stop mechanism is from a 70's machine. That means it will all be discrete components and should be fairly easy to repair.
If I were looking at it the very first thing I would do is check all the soldering and look for dry joints. The second today would be the capacitors and the third would be to look at the transistors. Another common source of trouble might be a bad joint in a wire, usually between the wire itself and one of the connectors.
@Mr Guru Not quite the words I'd choose, but solid advice. If you're a more visual learner you could use a circuit simulator to show you the expected voltages at every point in the circuit, and compare that - for audio frequency signals even a simple pocket oscilloscope (less than 30 quid off ebay) will let you compare expected waveforms.
@Mr Guru I agree that they're not needed a lot of the time, but, as you can see in this example, service manuals often include diagrams of what a signal should look like at selected points in the circuit. While 'knowing how to use it' varies depending on what you're using it for, even without knowing the full details of the workings of a circuit, a keen amateur, or a trained diagnostic repairman, can follow a block diagram and isolate the fault to a particular section by simply finding the point in the circuit the scope doesn't match the picture.
@Mr Guru Thank you for the MG328 recommendation. I just bought one!
Hi there, I love your videos. I am blind and the way you describe things is just great. Keep it coming. Love all this vintage tech that you’re showing. Takes me back.
Really nice video, Matt! I love the internal design of these 60s/70s Japanese electronics, they always show there was a lot of thought about maintenance from the start of a project, with foldable circuit boards and enough cable length to get stuff out of the way. I just wish they had less solder and more plugs and sockets.
I ran into the same problem of mysterious wowing, and in a very similar frequency to yours, a few weeks ago even after replacing every belt and cleaning every idler wheel I could find on my Sony TC-150. However, mine didn't miraculously sort itself out. I'm guessing it might be an old capacitor down on the power regulation circuitry. It only really bothers me when playing tapes recorded on the same machine, as the fluctuations in playback speed are added to those from the recording.
I rarely comment on videos but I must say I just watched a half hour video about repairing a cassette deck and didn't get bored or consider clicking off even once! Thanks man great video
9:03 - I wonder if the lack of plastic is due to the 1970s oil crisis.
Amazing video as always!
That would make a lot of sense...
There was a vinyl shortage in the 70s, and LP record quality went way down because of re-ground vinyl, un-sold records being returned and recycled for pressing new records with. I have a copy of Quadrophenia by the Who with bits of rusty metal imbedded in the grooves!
That was my thought. Plastic is a petroleum product.
Interesting theory! My PhD supervisor recounted how he and his colleagues worked on plastic substitutes in the 70s for this reason (which would have been environmentally sustainable, too) only for the funding to instantly dry up when oil prices came down again.
@@BlameThande , Henry Ford built an experimental car body entirely out of soy-based plastic. The biggest drawback that I can surmise is that mice and squirrels might find it particularly interesting to gnaw on, as they often did with some antique radios where the wiring insulation was soy-based.
I love how patient you are in these. I would've given up after taking a few screws out.
24:37 Wire-wrap was pretty common back then. I remember my dad even had a tool that would do it automatically (you pulled a trigger and it would spin the wire around the post). Antiquated stuff, but neat to see nowadays.
Long before my time but I know it was used quite a lot in prototyping back in the day. Surprised to see it in production hardware.
@@tyrgoossens It was fairly common in production in the 70´s.
Good vid on the subject ruclips.net/video/L-463vchW0o/видео.html
Correctly done it's actually far more reliable than soldering. I have worked in nuclear power plants and all connections in the safety control systems logic were wire wrap.
@@denislostinlondon199 I dont think i have ever seen wire wrap with the insulation in place, but i have never used the method myself, i started working in electronics in the 80´s.
Come on Techmoan, really no need to beat yourself up. You did a fantastic job fixing this unit. I know there are viewers that are critics of everything, but what you've demonstrated is that with a bit of patience and drive anyone can tackle something like this. Regards,
"Okay now, this was another mistake. I shouldn't have done this- it made things worse."
I need to make a little button on my desk that plays this clip for when I fail to fix things.
I'd probably wear it out.
Wow...I am so blown away by your tenacity to do things the right way and to finish the job to the end! I also admire how you video the good with the bad..You are definitely my go-to guy when it comes to fixing stereos and other components. Thanks so much!🇨🇦👍😉
All right, you won me over! :-D Been watching for years, and I figured your efforts deserve a little more than just the odd ‘Like’ now and then, so I got off my arse and joined the Patreon. Count me as well entertained (oh, and that little Polaroid CUBE+ cam still does the job) :-)
Whatever you do, do not feel bad about your repair and your ability. You saved another piece of equipment and you learnt. You enhanced your knowledge. It doesn't matter if other people knew better. Plus, you have probably got more feeling for the cassette recorder now. I recently repaired my 5yo amp. Although I was upset it broke, looking back I enjoyed it as it worked my brain and occupied me during lockdown. And you know what, instead of moaning about my amp for breaking, I actually find myself liking it more because I got tok now it intimately and deeply. Pat yourself on the back!
Really enjoyed this video-you have the patience of a saint-I salute you for getting it working again.Just a tip-sometimes a squirt of contact cleaner or deoxit in the motor speed control hole can fix a wow and flutter issue due to the speed control screw inside the motor oxidising-its just a variable resistor
Mike Eastridge yes agreed but I wasn’t recommending spinning it more than a couple of times back and forth with contact cleaner-which also acts as a lubricant-so the chances of damaging the pot are virtually zero-I’m an electronics engineer so I’d like to think I know what I’m talking about 😀😀😀👍👍👍 You could also leave well alone and put up with the horrendous wow and flutter 🙁🙁🙁
Me: There's no way I'm going to watch this guy fix a machine for a half hour
Also me, 30 min later: wait it's over already?
I felt the same way when I discovered Louis Rossmann lol
I know what you mean. I'm currently halfway through and I don't want it to end.
Welcome to the dark side - you are now one of us....
I guess I'm weird cause I said "ohh boy a 30 min one means it will be good....". To me he's pulling off small miracles by bringing these old gems back to life and I hope they keep coming.
Ikr
Thats a very calm “end of ones tether”
There was lots of Fing and blinding off camera for certain, and perhaps even a few Mo Fos
The most important skill to have when working on this type of thing is patience. Matt has that covered. Loved the video. I've watched it several times.
Thank you for the great tip - sticky taping the screws to a labelled piece of paper - I wish I'd thought of that last week, when I took apart a synthesiser! hahahaaa Great vid Mat. :)
@Bill Whittaker I did that, then the cat knocked it off the table; even if the lid's closed, everything gets all mixed together at one end...
I draw a rough outline of the part I'm disassembling and its screw holes on a piece of paper and push the screws through the diagram at the corresponding point I removed them - that way when I reassemble the device I can just follow the diagrams backwards.
My mate taught me to get a bit of thick cardboard and screw the screws into the cardboard. Done properly they won't go anywhere if it gets moved or knocked, and you can screw them in in the same pattern as they are on the device.
Marvellous viewing. When people say ‘ blimey - that was a dear do back in the day ‘ this particular example is self explanatory, highlighting the complexity and labour intensive building and content of electrical/mechanical consumer products and the cost associated of getting the thing past final test and in to somebody’s home. Having spent a lifetime in the industry from the dawn of colour TV to the present digital age and the rapid leaps in technology which most nontechnical people just take for granted can you imagine what the next 25 years hold for us all bearing in mind the stratosphoric advances in recent years - mind boggling. Wonderful content by the way Matt !
When I was a kid I was obsessed with flip clock alarm radios! Every time I'd see on in a store I'd have to go look at it and drive mum nuts!
@Mike Eastridge Ah yes one off my favourite movies and the bedroom scene with the clock radio 🤣
I very much enjoyed this video. It's a story, and has progression along the way of how you worked things out, changed your mind on things, ordered parts. It's not an experience you could've thrown together in an afternoon.
"mostly broken to mostly working" sounds like a Monday to me
never feel down about this sort of project, think of the learning experience you got. that education is invaluable.
Usually, for me "English" English is a listening nightmare, but Techmoan accent and pronunciation are quite nice and understandable, great! I enjoy it very much
I'm English and only understand one word in three! 😂
He has a Southern accent which is what English people on TV are usually portrayed with, so it's very easy to understand. Techmoan speaks very clearly any way. I'm English but can't quite pick out exactly where he's from.
When I was growing up I spent all my time dismantling things and experimenting with electronics. Over the years I've lost a lot of that confidence, but videos such as this really help to remind me what is possible with a bit of patience, care and attention. Thanks Matt.
23:07 The "flipping things died right at the end..." just after the flipping flip clock... flips.
Flippin 'eck!
What a gift you have of making videos like this repair just as entertaining as your regular content. Well done with the repair as well.
I'd absolutely love to see a collaboration between you and Big Clive fixing this amazing machine.
Just because you don't have the in-depth knowledge to fix the auto stop, doesn't mean you don't know enough!
We all have to start somewhere in our skills, and you took on this project and did learn alot!
I am sure your other skills are well established and you have the knowledge in them.
The thing that impressed me was that you did try, and learned alot along the way, even without a service manual!
Congratulations on your repair!
I feel like the guy responcible for that notch was on his death bed and he watched this video. After he appreciated his work the notch guy was able to die in peace.
Really like the look of this. It’s got so many classic retro features. Love that you push the cassette deep into the unit at an angle, then the 3D effect once it is housed and lit up. Tip to anyone restoring 70’s /80s separates - if replacing light bulbs-be sure to use yellow-effect ones. Bright, bluey or intense ones totally spoil the look.
Quite addicted to your videos now!
Techmoan is a man who suffers for his craft.
Discovered this channel a few weeks ago. I love seeing you grow and learn over the episodes. My very first midi tower was a Pioneer.Actually bought it for an apple and an egg. This is a saying in Dutch. When something is bought very cheap you bought it for "an apple and an egg" and an electronica retailer, wen opening a shop in my town in the early 70's, would "sell" a piece of equipment of your choice to the first 10 customers for an actual apple and egg. I was customer #2 and choose that Pioneer tower. When I later in life went for components I usually choose either Philips (National pride obviously) or for some strange reason Technics. (great brand but mostly mid range)
best Techmoan video of 2020, i loved the deepdive into that machine.
really glad you got it working. There's nothing quite like finishing restoring something like this - thank you for documenting it, and well done for giving it a new lease on life.
I'm looking forward to whenever you do fix that last issue on the circuit board, I'm sure some genius in the comments already has it sussed.
I increased my Patreon payment after watching this video.
Your issue with fixing things is where I stand with cars. I Know most of what goes together, but when people, especially in the Ford Capri community, do a task easily, i struggle. Learning these things take time and that's where the problem is in a lot of our busy lives. Really pleased you were able to get the time to pull it apart and get it working decently. Full pat on the back in my opinion. That wow and flutter, jeez!
small tip: try getting some JIS screwdrivers when working on these vintage japanese electronics
It doesn't matter if you fixed it or not, very entertaining, engaging, and honest. Thank you for your efforts.
I would try replacing the caps on that Auto Stop circuit. That seems like a logical place to start. After that I’d throw my hands in the air.
Like you just don't care? 😆
I was thinking the exact same. I performed that repair on my sling box back in the day and it worked flawlessly
First thing to do. If that doesn't help, one of the transistor will be probably bad. Order them too , they are few cent anyway.
maybe the c1419 power transistor
@@kkuukkoo2 only problem is getting obsolete parts! Probably not "hard" to reverse engineer and find suitable alternatives if they're saturating, which would seem likely in this scenario, but if they're being used in their linear regions it gets more annoying.
Everyone that repairs stuff for a living, myself included - all had to start from somewhere. I’ve always found the best way to learn about fixing anything is to just not be afraid and have a go. (Obviously within reason) what you did in this video, making a thousand mistakes and then working it out in the end to great satisfaction is familiar to many of us.
Congrats 1M subs. You've earned it!
This video shows a very clear difference in the way things used to be built to the way they are built now. This things like a tank!
Hahaha, Techmoan meme-ing hard again today, with all those 4/20 clock shots :-D
I believe you to have such a patient skill ... I love that you can show the level of your skill ...and also your limit ... I am always trying to improve on my limited repair skill and watching your video gives me a new found hope ...thank you ... Please continue to bring color to my world ... Raul ...