I was going to throw this thing away
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- Опубликовано: 5 окт 2023
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When this MCS (Modular Component Systems) Model 3233 receiver showed up on my bench, I wasn't sure what to expect. After lots of troubleshooting, it turns out one of the most critical components on the chassis had failed.
Pure deadpan comedy when you talked about ordering the $20 transformer. The look on your face was priceless lol
Hi. I really enjoyed watching your video - my first time on your channel. It is nice you have the presence to let us see the whole you and not just some disembodied hands! And to see an honest process in the repair, good and bad. Heck, we all know it seldom goes smoothly. Well done.
In 40 years of working with electronics, this is the first time I've ever seen a failed ceramic cap. Nice work!
btw, if you get something like that you can't/decide not to fix, dont take it to the recycle, offer it up to someone else
I had a few MCS components. This host sure is handsome.
Like many here, I have a soft spot in my heart for MCS components. My first real "Hi Fi" system was a complete MCS system from the back of the JC Penny catalog for about $269 in 1978 or 1979. I got it for Christmas and it was still a lot of money for my parents. I can't remember all of the model numbers, but it had a 15 WPC receiver, Dolby cassette deck, a Technics made turntable (one of the best parts), and some sort of kabuki speakers that were just ok. However, at the time I thought it was FANTASTIC, Glad you are keeping MCS alive. No, it isn't Pioneer or Marantz, but it was still magic to me.
An excellent video about a problem unit. However, I hope you don't think that completing the "the little things" isn't worthy of another video; it would be great to see it all come together!
Most of those were made by Technics. They were decent receivers sold by J.C. Penney. Those wee rated at 33 watts per channel RMS. Which would have put it in the middle of the pack for MCS in 1979. They were likely similar to the SA-300 Technics receiver from the prior year or two.
You'll often find that many 'house' brands like that are simply older model, rebadged, sometimes slightly redesigned models built buy one of the major Japanese manufacturers. Sometimes the are just last years model from a different market set us for US sale too.
The MCS receivera were not made by Technics. The cassette decks and turntables were. The Japanese built ones were NEC, the Taiwanese built ones - who cares, they were garbage.
All the one's I've come across were flat out Technics rebadges. I've got 9 of them here. A few were NEC but not many. From what I've seen only the top of the line models were NEC. In the 70's, nearly all the Technics and Panasonic receivers were still made in Japan. The 3233 was from 1978-79. I have one here. The 3275 was built by NEC, as was the next two models above that. Take a look at the amp modules in a Technics, a Nad 7080, and the MCS 3275.
In 1980 I bought a complete system from JCP, (they were closing the local store and had a killer sale).
The amp is a 3835, with matching 3700 tuner, the TT a 6502, the speakers are 683-8227, Cassette deck is a 3562. I went back a week later and bought a 3865 as well. Each component has a direct matching Technics model. The boards in the 3837 and 3862 both have Matsushita right on them, the TT is a Technics SL, the cassette is a blatant rebadge.
On the amp, the Technics came with a few more options, but on the MSC, that area has a plastic plate over it, sort of a filler plug.
Sound wise, its decent, on par with any other mid range equipment back then. I did a full recap on both the amps and the speakers a few years ago and it brought them back to their original quality or maybe even better. I'm sure my ears aren't the same as they were when these were new.
A buddy has a 3125, which is made by NEC, that model was rated at 125wpc.
I pretty much have always figured that the part number denoted the manufacturer, as the 3275 was a very different model both in output and design. The 3125 was a piece of art inside compared to the more generic looking 32XX models which were often hard to tell apart from a Sanyo or Fisher of that era on the inside.
@@mdzachariasyup, it gets old hearing that Technics made the receivers just like it gets old hearing pioneer built realistic
It definitely doesn't look like a Technics design inside. It loosk more like a rip off of a Pioneer design. Very little of this receiver looks like Technics. Now I admit to not knowing the MCS brand or JC Penny as we don't have either in Australia, but I have seen a lot of Technics equipment.
Matsushita is Panasonic (who use Tekunikusu "technics" for their audio , so you are indeed correct
My Dad bought a complete MCS system in the 70's from JCPenney and I still have the turntable. As a boy I remember being amazed at all the cool features it had. I hope you get it back in good shape and give it a new life. These systems really were high end audio hidden behind JCPenney's house brand.
I enjoy watching you hammer through so many possibilities on troubleshooting. How to know when to give up is always a fine line. Maybe sometimes just the challenge of figuring it out. Nice work.
Figuring it out IS the pleasure. No stone unturned.
I've seen a few ceramics go shorted like that. Always replace all even if just one is bad. Also had larger ones across the secondary go dead short with no visible damage at all. Not common, but often enough to make me check early on the the process these days. The transformer was likely damaged by someone fitting a much higher value fuse after it blew the first time.
Yep I've had a few amplifiers have dead ceramic capacitors over the years too.
I had many MCS components when I was young. Technics indeed made all their turntables. The platters even have the Technics logo on the bottom side. JCP sourced these things through a few different manufacturers. NEC, Technics and Pioneer I believe, depending on the model and year. They even had some seriously hi powered hi-end models as well. Great video! I am sure this model will sound great once you get the pots all cleaned up.
NEC made the majority of the receivers
Well done on nailing that cap! It's worth re-capping the whole power supply, which I guess you will do.
I really enjoy your videos and would actually love to see a follow-up on this one, with all the little details taken care of. Thanks!
The "scratch filter" must be a 10 khz 12dB per octave filter. It was very common on 70s/early 80s amplifier and receivers. Used for filter clicks and crackle from not exactly new vinyl records.
When I saw this, I was thinking, "yeah, that 10 volt zener diode on the amp board is shorted". But apparently lightning struck and popped the disc cap on the rectifier. (They put those across the diodes to stop switching noise on AM broadcast band.) Then the goobers put bigger fuses in til the transformer popped, or possibly the lightning strike shorted the transformer primary and the disc cap at the same time. These units were made by Matsushita for JC Penny. My sister had one. They're entry level hifi. If you put properly sized speakers and properly sized fuses in them they'll work OK and not pop your speakers. My sister's reciever would cause the cones of the woofers to pull in sharply with a loud "wump" when you turned it on. I always wondered if the speakers were gonna pop, but hey never did. It worked for many years. Then finally, it failed. A 10 volt zener on the power amp board shorted. When you turned it on, there was the loud "wump" and heavy 120 hertz sawtooth hum from the rectifiers. If you had left in on for more than a couple of seconds, it would have blown the speaker fuses.
In 1980 I was making products for Jc Penny. They needed cheap cost. Our factory provided garbage. What a perfect match was.
Respect for bringing an otherwise discarded and unappreciated ancient relic back to life. You're a saviour!
Great job man.. it's not the unit that matters here, it's the lesson ! Thanks for making this vid :- )
Normally you shold start from power supply. But I understand that in such a situation the video would be too short... Either way, you've succeeded. Congratulations.
Lucky man, finding that transformer, a lot easier than rewinding the original.
Low filter and scratch filter are used for phono - you are showing your youth.
I like your electronics knowledge, and your spirit for not giving up too easy. As an electronics enthusiast for nearly 50 years, I'm happy that the trade is in good hands for the future!
I bought this same model at a flea market years ago. Cleaned it up, did some recapping in the power supply. Very surprised! It sounds just fine, will drive any speakers and it is cool looking. It is a nice piece.
Wow! You managed to discover it was transformer was faulty and lucky enough to find one at ebay for a good cheap price. And found the other fault and got it working. Very cleaver. Look forward to seeing you clean it and put lights and fix knobs and Dexoit. Will be a good amp when it is completed. Always enjoy watching your videos. Catch you soon.
Love it.....great troubleshooting. Thanks for taking us along. Nice one.
That’s an extremely rare find. Disc capacitors are the most reliable of all capacitors and really almost never short. I can’t remember if I’ve ever seen one shorted or not. The find of the transformer was a lucky one for sure. It was great to see this get repaired. I wouldn’t have made it that far with a shorted power transformer. That would have been it for me.
yep, ceramic failures arent common and its mostly in high voltage circuitry,
Very unusual. I'd say it got physically damaged once, and then arced and got worse.
@@kenmore01 an unusually high voltage spike on the mains could've caused breakdown
@@andygozzo72 yes, but it would have had to be a very high surge, since it was on the secondary of the transformer and I'm thinking the voltage peak on it normally would be around 50V. That cap would have at the least a 500V rating.
@@kenmore01 a cap on low voltage secondary very unlikely to have a high voltage rating, i've never yet seen one in that sort of position have a high rating, usually 50 to 100v, depending on the ac from the secondary
Love your perseverance, and logical approach. A learning experience for me, much appreciated. ❤.
I had an MCS unit in the early 80’s. I think it was the same as this one. I thought it sounded great for its time. Wish I still had it.
A shorted ceramic, in all these years I don’t think I’ve ever seen that one. Great find!
very well done. I enjoy learning from you. Keep em coming
Great job sourcing the issue(s) and resolving the the matter at hand! This was a very informative and entertaining. You know the usual. Thank-you and have a great Canadian Thanksgiving weekend! I know I will. L💞ve from Canada.
Fascinating work. Great job.
I still have a Technics AM/FM tuner with MCS badging. It is still working. Got it at the Penny's Outlet in Columbus Ohio (RIP)
Great repair and nice device!!!! Thanks for great vid.
I have one of these up in my closet I bought back in the late 70's. It was great for the time.
Seeing that thing takes me back to when I was a teenager. My friend had a brand new one was a little bit earlier model than that with a turntable and some advent speakers. It really did sound pretty good.
I remember these audio components from the 70's. They were on the low tier, lower than Radio Shack's Optima line. The thin sheetmetal and MDF cabinet construction coupled with the sloppy PCB and wiring layout, assured that these were the lowest of the low.
Awesome troubleshooting. I like your procedure and your Jazz music.
That was really enjoyable viewing,ive taught myself most things and was totally on the journey with you but unless i had seen the burnt ceramic disc i would have failed
One of my receivers is a Sansui 9090B Love it. Rebuilt and calibrated, about 4 years ago.
When I worked at an electronic store in 1973, the audio tech was authorized to service J.C. Penney stuff. Many of the products had a fault right out of the box. Many things either failed to work or failed within the first few hours of use. The actual MCS line came around a little later.
I just encountered the same shorted ceramic cap issue in a Kenwood receiver, also located at the rectifier. Visually burnt and shorted. Replaced the cap and it started working again. Thankfully the transformer was okay!
I've seen another video where they carefully pulled the xfmr apart and found a thermal protection (thermistor I think) that failed open. They wound up pulling that out and bypassing it. It is obviously not that same failure as yours but a good thing to keep in mind if you ever have an open condition.
A 1 cent cap, takes out a $20 xfmr. It may have been a big surge popping that cap or maybe a lightening strike. No xrmr protection, and thus the failure of that winding.
Great detective work. Always amazed that a defective part the size of a dime can disable a component, or at least make it sound bad. Good to see you back doing the Hi-Fi repair videos. Let's see the rest of the MCS 3233 repairs!
Thanks! I was just working on a bigger issue with it last night and tracked it down to another failed capacitor.
Some transformers have a thermal fuse inside the outer shell, but if that was the issue the light would not light up at all.
If the transformer overheats they open the primary winding. Thanks for sharing this receiver with us, it was much enjoyed.
Thanks for doing this video; glad you turned me on to DG Wojo .
Mate love this channel. I know it's not ElectroBOOM, but I watch with nervousness when I can see the mains lead in and the DBT on and you snipping primary wires etc. Please take care, with your distraction from recording etc.!
Great job sir !! Would love to see it all lit and functioning.
Great save on this receiver. It could make a young man/lady very happy as the owner of a vintage music machine. I hope more "kids" get interested in the "hands on" kind of hobbies and work. We really need trades people who started learning their careers at a young age.
Wow! I had that receiver back in the 70’s! I believe it came from JC Penny’s I purchased with a pair of Panasonic 8” Thruster speakers, an MCS dual cassette recorder and turntable! I still have the speakers and cassette deck…. I don’t remember what happened to the rest!
Oh yeah, I retired mine because every pot and switch got very noisy! But it played for many years!
you did good getting it working with replacement trans good job
good job as always
Nice job Aidan👍👍 A bit more elbow grease and this receiver will be ready for a price tag, somebody will love to have it. Being a department store brand doesn't necessarily make it a low quality item, it was just a re-branded secondary product line from a major mfg. like Panasonic. It'll look good cleaned up some. Thanks for the video. See ya next time.
I would guess a lightning strike took out the transformer and that cap. You might want to look into purchasing a variac (variable autotransformer) and add an inline ac current meter if it does not have one (replace that light bulb setup). Safer for you and the equipment you are working on by isolating you from line voltage as well as providing a variable AC supply to bring these things up with. For checking an output section put your DC meter across one of the output emitter resistors (checking the bias current) while you bring up some "unknown" receiver / amp and not risk blowing up more stuff. By watching the AC current meter, you can always see what is happening prior to smoke and or destroying other components. (I worked on this stuff for 30 years or so and would never touch a receiver or amp without a variac. Sencore made a variable AC supply PR57 (which I still have...) but it is limited to 4A so not for the really big power amps. It looks like you can pick up an inexpensive chinese 20A variac for a bit over $60.
Great job
Well done !
VERY rare problem, in the day I would have hired you.
LFOD !
Well done. That ceramic cap was probably poorly manufactured and it took the transformer out when the associated winding was effectively shorted out.
Excellent job and love seeing deductive reasoning at work. I’ve got a Pioneer receiver and the infamous Sansui Quad to work on and thanks to you I may have a better chance of success. I wonder if a film cap has a better survival rate than a ceramic cap.
Matsushita made. basically a Panasonic . I work on quite a few of those. MCS are one of my favorite rcvrs . I usually get rid if the speaker fuses and install a relay style protection board .
NEC
Hey good work on finding that ceramic discs are one of the most unsuspecting components to be shorted and often are overlooked because they are not known to short very often.
My immediate reaction to its styling was "Optonica" (made by Sharp),
but Panasonic made some that looked similar.
Nice job 👍
That was my first thought too. "Kenwood". 🤣
Scratch filter is for phono to reduce scratching sounds from vinyl.
Resistance was going up because your meter was charging the filter capacitors in circuit. That's the risk of measuring things in circuit. The negative ohms was likely due to some charge on the capacitors also. I am not sure why they designed this with the caps across the diodes of the bridge rectifier. Maybe some kind of noise filtering, but I don't think it's the best design.
Good that you saved this amp from landfill, though I am not sure it was worth the cost of a new power transformer. Nice for a video though.
They’re snubbers to reduce ripple from the diodes, pointless if you run enough filtering after the diodes.
Good job!
What you've got there is a "generic brand" built by Foster Electronics, in Japan, late 70's (1978 / 1979)
Which is a subdivision of Matsushita. Ignore if anything on the device states another country of origin, this is where it was manufactured. It was common that many (european) brands let them put "of the shelf" components together, using their own faceplates and voila. (In this case) A new budget brand was suddenly born.
There. Now you know.
Surprised you don't know this, It's quite common knowledge....
Fake news NEC built these
@@danielknepper6884you have no idea.....
Some were made by Technics, some were Hitachi. Were great for the budget hifi or starters for the teenage crowd.
glad you saved it.
Great to see that with the popularity of the vintage market that there are young guys that are interested in fixing them. It might be your hobby now but you will be getting bombarded with service work and you will be able to name your price. So much so that you will be able to make a very livable wage from a “hobby”. I have a Sansui 800 and I’m in driving distance of you so maybe I can coax you into re capping it for me. Well it’s a little drive to your location but I will do it if you will work on it. You can film it for your channel even. Tampa is close to you, right?
It's negative MOhms because there is still some charge on the cap.
Electrolytic caps are the culprits most of the time for me. The plates of the cap will collapse and touch and create a short unless they have voltage on them. Unplugging a device and sitting it on a shelf for a few years will very commonly kill those electrolytics. Most of my equipment that I rarely use is kept turned ON all the time. I have several amps from 1980 that have not been turned OFF (except for power company outages) since 1980. They still work just fine. Other gear that I left unpowered for about 10 years all have bad caps.
The devices like my guitar amps that generate lots of heat when ON are on a lamp timer and power is applied for 30 minutes every day.
I vote for another video to see it all cleaned up and working at full strength
A ‘scratch filter’ was to help your LPs sound a bit better.
These ceramic caps are rated about 63V, one mains peak and the next one goes. I would definitely replace all four with 100V types. Cost you two dollars.
This is great I found you of these at thrift shop for $10. Please share the service manual.
MCS were sold at JCP. Their turntables were made by Technics. Looks like it has Main/In Pre/Out jacks for an equalizer.
LedHed Pb 207.20 🎶 🎸 🎹
Yep I've had a few amplifiers have dead ceramic capacitors over the years too. First thing I do is a visual inspection for anything obviously burnt, second step is diode test bridge rectifiers, power rails and outputs for shorts. Megohm test the transformer primary to ground and mains lead ground resistance if it has that.
One amplifier had me stumped for a little while, everything looked good but it would draw to much power when on, turns out the soldering was really bad and the center tap of the transformer was open, this burned out and open circuited the bias transistor that i failed to measure as it was hiding in the heat sink.
Brainiac work!!! I'm trying to find some "output" resistors for an old Scott 1968 stereo we've had since new. Zero sound out the speakers. Had someone test it and said 2 of the resistors tested bad. Can't find them to save mylife. Part number says Bend QP-11 0689D. Can't find a cross reference for the T03 style resistors. My receiver will light up when I spin the radio dial to a station but zero sound comming out of the speakers. I worked fine up till a few years ago and then went silent
Thanks!
Great diagnostic video! Did you replace the other 3 caps on the rectifier diodes so they don’t suffer a similar fate and kill the new transformer?
Wow very lucky to find the transformer normaly thats game over for the old stuff. Those ceramics across the diodes are there for extra filtering like high frequency transients and stuff probably put there because of poor filtering later on!! because ceramics are cheap electrolytic caps are not. Personally I think they are not rated to be there and hence a very unusual failure, you just don't see those little guy's freak out like that but you got a great deal on the transformer, however I wouldn't spend any more money on it ! not worth it. Great video...cheers.
The "scratch filter" is for when you play an LP.
Yep - late 70s with early 70s components in many cases. Atonly 33 WPC, it may not need big heat syncs.They sounded pretty good.
I have one. Exceptional sound. Never scrap. Knobs, faceplate and other parts have value.
Tell us how it sounds. I like mine . 0:01
I have a similar unit. It's Audiovox, or Sound Design (don't remember what it was.) I couldn't find a transformer for it. Instead of plugging it into the wall, I just run it off 14v DC. Easy enough to find a power adapter.
First half of your video .... As a quick test, you could have unwired the transformer (as you did) then apply a signal generator say at 5v rms at 60Hz to the primary, and observe the various outputs either with a scope or with a meter. Just a thought. ;o)
Now, I'm watching the second half of this video ....
A 5 cent part takes this thing out. Never seen a ceramic cap go bad.
This kit has had a tough life it seems.
Love your videos. Just starting to get into this hobby and I'm getting alot of info from you so thank you for that. You make it look easy! My question is where do you go to download the schematics ? HiFiengine is not accepting new registrations at this time. Is there a different site I can go to for them? Thanks for your info !
A scratch filter is a low pass filter to eliminate record scratch or noise.
MCS wasn’t too bad. Of all the department stores, JC Penney cared about the quality of their products. The scratch filter switch is a high filter to reduce pops from scratches in records. The matrix switch turns on the matrix quad decoder.
@AH-Fix-It -
Despite me having far less experience in this than you do, my first thought was "Power Supply" (transistors/capaciors/diodes/transformers or a loose screw got stuck) as this bulb lighted up and you said this is a bad sign & I do visual inspection + a sniff test (for burning etc) before touching anything (OK the sniff test might not work so great if the device comes from heavy smokers) ... OK I don't do radio receiver + amplifier maintenence, but in my free time I change defective computer components and my fist look is always on the sticker of the power supply if the PC is not a big name brand ( = supecting a cheap one thet might kill stuff or is just defect, because users to often by the cheapest) and testing it ... followed by the grafics card (due to it´s value) if it´s a gaming PC
To answer the presenters question, a scratch filter removes some if not all of the noise from scratched vinyl or tapes.
Nice to be able to step back if what we expect is not the right path, especially in unfamiliar territory.
sometimes there is a fuse inside the transformer if you can take it apart
Shango066 always says to take time to visually inspect before digging in.
True, and I can easily imagine it was not visible or easily visible from his perspective. Would have been a great visual inspection catch. Transformer was still cooked no doubt.
Well done. “You won’t die until I tell you, you can die!”
electronics like this are ALWAYS made by the big guys.....usually REALLY great pieces too!!!!(that looks like
Pioneer)
ceramic caps dont go bad often but its almost always complete short or nearly short, rarely open or low capacity , they fail more likely in high voltage circuitry line line output stages or switch mode power supplies