"Trust what's on the board not what's in the manual..." Ha yes! I write code for a living. One of the first things they taught us was it maters what the computer does - not what the manual says. Great video thanks for posting it!!
As a retired electronics tech I can say that this is good advice. I've subscribed because your video is clear & succinct and not padded out to 30 mins like many others do.
Love the "Recap one section at a time" advice. As much as it sounds like a simple and easy thing to do, I was many times tempted to just keep going (for 5-6 hours ) . It is a very good advice so ty.
If you have a 1930's radio with old dripping wax capacitors and electrolytics and it don't power up. I fail to see how doing a section at a time helps. If your radio was working, why are you recapping? Thoughts?
Great advice!! I'm guilty of the shotgun approach because I wanted to listen to my vintage receiver right away. More than once, I spent more time trying to figure out where I went wrong with my DMM, hooking up my DBT, reading voltage/current values through everything and trying to read the blurry values from a scanned service manual, playing the AM/FM tuner, hooking up a turntable and using the phono/EQ board, etc. etc. You get the idea. Take your time. Do one section at a time, and then test your receiver. Another piece of advice is pay attention to the orientation of new transistors vs. old ones. Some older transistors tend to have EBC instead of a more modern ECB.
Great video and full of info. Had VCR many years ago with Alzheimer's. Sometimes responded to controls sometimes not. After hours of troubleshooting and consultation with others in the biz, turned out it was an adhesive foam pad (several) on bottom of circuit board between it and metal bottom of machine. After removing pads found affected traces in different states of degradation . The adhesive had eaten into traces and was semi-conducting between them, thus the Alzheimer's symptoms. No clue until pads actually removed to see damage. Rock solid after repair. Do not underestimate any "material" on a board to cause trouble.
Two important issues when recapping with a higher value; 1. never do this with starting capacitors in motors, they need the exact right value. 2. Recapping with a much larger value in a power supply can cause damage to the bridge rectifier, because the current peak when staring up, is much higher then. An other important issue is the temperature which is mentioned on the capacitor. The switching power supplies before the 1990's often used capacitors, marked with 85°C. This was also one of the reasons of the caused problems. Always use 105°C capacitors for switching power supplies!
Nice to hear someone talk electronics. September of 80s when I started working electronics. Who was the best thing that could have happened to me. I still use my skills on fixing vintage cars. I can handle anything electronic. I'm an expert digital troubleshooter. I operated on oscilloscope and a digital voltmeter like nobody else. This is no joke, I literally show this guy that with my hand over the board I could find the problem. He went to get the chipper placed and he wants to know how I did that. That man had three days working on that card. I still do stupid stuff like that. I love having a witness around see the things that I do.
What's nice about troubleshooting stereo equipment is that the channel that is in good working order can be a good reference for measurement comparisons. Hard to find problematic components can be detected this way. Just make sure that your reference input signals are exactly the same for the left and right channels. An oscilloscope can also be an excellent visual aid to compare for abnormalities in the defective channel.
I order my caps from Mouser because 1. they typically have good prices, 2. they usually have what im looking for and in stock and 3. I order over the phone to do Will-Call because I live about 20 minutes from the warehouse and I can typically have my Caps the same day or next day and avoid the shipping charge altogether.
If you're recaping really old stuff (20's and 30's era), capacitors had a lot of internal conductance that was accounted for in the original circuit that new capacitors don't have. You may need to add a resistor in parallel to keep the circuit 'in tune', and guessing the size of that resistor is really just a guess.
I recently replaced the electrolytic capacitors in a GE digital tuned clock radio from the late 1970s or early ‘80s which was too nice to throw out. Being on for 40 years 24x7 took its toll. The symptoms were erratic operation such as the alarm beep going off at random times and poor audio quality. As I pulled the capacitors, I checked them with an M Cubed Electonix impedance bridge and found about 1/4 of the capacitors had only about 1/3 their rated capacitance. Quite a few capacitors had also developed unreasonably high effective series resistance, as much as 30+ Ohms. After my order for capacitors of the same proper values and withstand voltages arrived from Digikey, it took a few hours to swap all the electrolytic capacitors. Since there were so many off value parts, I decided to replace all of the aluminum electrolytic capacitors so that I would not have to go back to replace more parts later. After a few hours of patient work, everything was good to go and the radio sounds great again. If you follow the advice in this video you’ll almost certainly have a good outcome with more life from your old equipment.
One thing I would add, having worked on computer monitors in the past ( 25 years ago) some brands had that hold down glue that would over time become unstable from heat and age and become conductive on the board. We had to scrape it all off and clean the board really well.
lol yeah the white glue is okay most of the time, but that transparent stuff is nasty. Another fun one are those fancy looking motherboards with chipset coolers that have stickers/decals on them... those come loose over time because of heat and get trapped in the fans.
KRK monitors had some black stuff where the liquid would seep out and cause corrosion, the rest of the glue became brittle. Have to remove that and hopefully before components are so wrecked you can;t even see what they were
My expectations were low when I started this video, I was expecting "don't reverse the polarity of electrolytic capacitors" and "make sure the foil end of the capacitor is connected the ground side", neither of these points were covered, instead all the tips were fresh and thought provoking. Very enjoyable!
I thought I was pretty foolproof in identifying component glue, but in your example picture I would've been convinced that the upper right and lower left pics were leaked electrolite. I work in electronics and am working on getting into restoring (and in some cases modernizing) antique radios as a hobby, so videos like these have been good for picking up on stuff I wouldn't have realized right away with vintage stuff. Great video.
This video is excellent, your methodology is all common sense for anyone experienced in servicing electronics. However, when it comes to factory glue, even if you can still identify it correctly, you must remain cautious and always observe precautionary. Some of these glues have proven corrosive or decompose in corrosive material, so if you notice oxidized copper tracks, rotten component legs, you'll probably have to remove that goo, restore PCB and probably change all components touched, resistors and semiconductors. Leaky caps can also smell badly: most of leaky SMD electrolytic capacitors include a fish oil impregnating everything. And here is also an important point, most quality electrolytics can still work fine after years if used and stored in proper condition. You also need specific equipment to check and test if they really need some replacement: you should measure values and ESR, and for specific uses like high voltage ones, a specific leakage test has to be performed. Of course, with experience or proper documentation, you have a number of specific condensers you will systematically change in 100% of equipment, mostly because their replacement is critical and always cheaper than the component they protect, like high voltage decoupling caps in tube electronics. And when it comes to components locations or sense, wiring and so, it's also interesting to take a number or pictures and notes along markings. Rule number one is to take the necessary time to observe and analyse any further action.
A possible exception to your suggestion against "shotgun" recapping is when restoring very old equipment. 50 or 60 year old electrolytics are often shorted, or nearly so. Turning on the equipment with such caps in the power supply can cause serious damage. The same applies to interstage coupling caps in tube amplifiers. If those are electrically leaky, B+ will flow to the grid of the next stage and that is also damaging.
I shot gun the caps in my vintage repairs. These caps are 40+ years old and way past their lifetime expectancy. And for s**ts and grins, I 'll use my ESR which says "yep.. it's fine" and use my old Heathkit leakage checker. 80% of the "good" caps fail leakage tests. The exception to this rant seems to be the smaller electrolyics normally used in the radio RX boards for example. Most of those I replace with WIMA anyways.. I hate having to redo my work. And fixing a unit just to have a ancient cap fail a few laters is stupid. I also replace driver transistors for the same reason. You have no idea how abused they are so I just replace them since I already have the unit apart on the bench. Zeners go to for the same reason. Carbon resistors in amplifier boards get replaced because most of drifted a fair bit and will continue to drift as they age even more. And I should say, I don't "repair" my projects.. I "restore" or "rebuild" them.. just like a car. And lets be clear.. this is my opinion.. nothing more. Everyone is entitled to their own opinion. My clients are happy with mine and how I do the work :)
@@MikeSweeneyMedia , Yeah, if you have to undo the dial string mechanism in order to pull up the RF, IF, and/ or MPX board (often those circuits are combined on one single long PC board), you want to be really certain that recapping is done with known good caps, and that you fix any problems or potential problems before you put the whole shebang back together.
Yes, better to replace the electrolytic and paper caps than destroying transformers and such that are made of "unobtainium" now. I do the same on old tube stuff.
I particularly liked the point that there are factory mistakes as I have found several over the years but did not know about mistakes in service manuals nor was I aware of silk screen mistakes on circuit boards. Thanks for the info.
Great video with lots of good points. I would caution about using a replacement electrolitic capacitors with with a voltage a lot higher then the original. Such as putting a 350 volt in place of a 25 volt because it won't stay properly formed with the lower working voltage. While it is not in the scope of this video, all that glue on those circuit boards, that some over time degrades and becomes caustic and conductive. As long as you are replacing the capacitors, you should remove the glue as well. Once again this is a great video, keep them coming when you can, stay safe and have a wonderful holidays.
Yep, and there is something else to consider too. E.g. with modern switching power supplies, ESR (=equivalent series resistance) is important. Higher voltage caps have higher ESR than lower voltage one with same capacity, which is a bad thing. So, going a little higher may be ok, but not much higher.
Excellent video! Always good to hear from techs from the good old vacuum days when things were made in the good old USA and everyone was employed. Sylvania, Westinghouse, General Electric, Magnavox, Panasonic, Admiral and many more. In contrast to present day times, I treasure those days. Thanks for sharing.
@Andrew_koala I agree with your comments on lower shipping fees from the US. I see many excellent US products new and second hand. However the shipping costs for customers in Australia can sometimes be quite a bit more than the goods themselves .. A real shame actually. I have one or two old pieces of test equipment made entirely in the US. They are very satisfying to use. Thanks for voicing some interesting thoughts.😁
Great video, with many good points raised. Re: not trusting board markings. There's at least one infamous example in the computer world: one revision of the Sinclair ZX Spectrum shows incorrect polarity markings for one of its capacitors, which has caught many people out over the years (resulting in many dead ZX Spectrums in the process). As for marking capacitors i.e. the "measure twice cut once" tip, taking clear high res photos of the board you're about to work on _prior_ to starting on it is also a very good idea IMHO.
Nice video! I use to snap a bunch of pictures of the PCBA before I start working. Nice way to keep track of orientations, values, and such. It has saved me a few times with bad PCB polarity markings as you showed here.
Thumps up Often I take pictures with my wirless phone. And every time I mark the capacitor (and the orientation from connectors). I use often diffenrent colours. I mark capacitors on top and at the PCB with a small dot.
That glue when it turns brown, instead of yellow, is actually CONDUCTIVE. Especially if it is near something that is starting to corrode. I've fixed many malfunctioning electronics just by chipping that glue off. When it turns brown it becomes brittle facilitating this.
In the past I had resolved CPU problems as well due to the heat sink compound getting on the CPU pins or on the visible CPU circuit. Wiped off the compound on those pins or other contact points and the computer worked fine then..
EXCELLENT VIDEO. Thanks. I am working on a little sound board of a 1970 arcade game that uses electro-mechanical pinball technology. Even a little sound board that only makes three sounds has 6 transistors and 37 capacitors. Half electrolytics and half "tropical fish."
All really great advice, re-capping is a great way to generate tears of frustration if you do it willy-nilly. I would only bother if the gear has a real problem.
These are the types of videos that help me the most. That cover all types of electronics not just radios and such. I repair vintage and modern electronics, mostly test equipment and industrial electronics. A lot of motor drives, PLCs, and a lot of automation control equipment. I do see a lot of 1980s equipment that is still in service so I recap and repair a lot of stuff like that… And these are the videos that help me the most. Although I do enjoy radio repair, I don’t do it very often so these general subject videos that cover a broader range of electronics are extremely helpful!
All good advice. A short version of the quality points, don't be cheap! Mouser, Digi-Key, even over the counter, if it's still an option for you, is better for jobs like these. How much is your time worth? How much is the gear to be repaired worth? How important is your success rate worth to your business? Spend $2 for one instead of the bag of 100 for $5 online. I worked at a place many decades ago that had a sign: If you don't have time to do it right, do you have time to do it again?
I am preparing to do some repairs on my Tascam M-30 and Teac Model 5 mixers. This is a great list of things to know and I'm grateful to learn these tips before I dive in.
I am a retired electronics engineer and HAM radio operator. I worked in many different types of design disciplines . I also restore equipment. I am aware of all you presented and I love my subscription to your channel. I watched this one and am impressed how well you presented these common mistakes. I have friends that shotgun and who mistake the wave-flow or retention glue for leaking capacitors. In tube circuits friends with guitar amps typically want to up the capacitance which has caused them many problems. I am trying to work with them and they say I'm a perfectionist or taking too technical of an approach. These same folks do not embrace ohms law and also try to check caps and other components in circuit with a Ohm meter in diode mode. Sheesh.... I'm trying to teach them, but I will pass your video along to them. Thank you so much ! I am currently designing my own Class A and AB1 amplifiers, All tube and Hybrids and you have helped me immensely as designing tube equipment is much different than servicing Them. Thanks Again !
Your videos are fantastic! I have a professional lounge organ; a Wurlitzer 805, built around 1975. The voices haven't worked properly in years, and I have come to learn that the power supply and switching boards are the prime suspects. I thought I would have to replace the capacitors with the exact same parts, which I was trying to at least find a source for before I started disconnecting and testing. The search was unsuccessful! Your video gave me confidence that I can restore whatever caps these boards need by following the tips and procedures you showed. Thank you for loads of valuable information!
This video content is excellent. What you covered in 10 minutes took me 10 or more years to stumble across as a circuit designer. This video is a keeper and a "must see" video for anyone with a soldering iron. Thanks Mark.
Thanks for the flag up on the potential issues with board markings and service manuals. I've come across it myself, so what I always do is photograph what I'm about to remove and always refer back to the photo when I'm replacing.
I have been working on vintage electronics for most my 60 years. and your video did make me think of a few things I had not considered. I often take a photo of boards to use as reference when recapping etc. Often a wire might break from moving things around and you are scratching your head where it came from.. And recently it came up that going too high in capacitance and voltage even in a power supply can be a mistake.. filter design depend also on resitance and inductance loads.. and even a supply is partly a filter.
It is really valuable author' advice with markings. Simple and clear. Also not bad idea today is to make sharp photo of board (with flash) with parts and connections in original placement. And to study original schematic for tracing damages - this saves unnecessary replacements which do not help and degrade overall condition .
When I derate caps on a recap job I usually derate on the next voltage up, no more. I always test new caps, you never know. I always test the caps coming out as a learning experience. Good video.
@@philhemenway3503 not a bad idea, but depending on how hard it is to access the boards or get them back into circuit, that could really add up in time lost! One section at a time seems reasonable compromise
This is a good approach, for a few reasons. First, the electrolytic capacitors can lose their "forming" as the oxide which is the actual dielectric is created maintained by applying a DC voltage across the capacitor. So a capacitor rated for a much higher voltage may age faster with little voltage applied to it. Secondly, the next person who replaces the same capacitor is even less likely than you to have the schematic for the device, as it becomes more obsolete and forgotten about in the future. So they will also see the voltage shown on the capacitor as the minimum value it should have, and possibly increase it. They most likely won't reverse engineer the circuit unless it still doesn't work after the recapping. This can eventually lead to a ridiculous voltage rating that raises the cost of the repair.
I think your video is great and useful because a lot of electronic related video on the internet does and suggest very bad advice that create more confusion than clarification.
thanks for the insight of your experience, no wonder i followed through my amplifier’s service manual , even looking at the board themselves, and just to fry out poping my capacitors eventhough i believed i had done everything correctly. As much as i love my amplifier, taken extra care and steps , sometimes things happens.
Remember the era when people used to mount their amplifier directly on the subwoofer box itself? LOL I made a lot of easy money repairing amps because the vibration had shaken loose anything heavy or tall. XD (the amps were usually mounted sideways)
On an old R-R tape recorder that I recapped recently, the electrolytic caps had a stripe on the side to indicate polarity. Unfortunately, as I discovered after replacing many capacitors, the stripe on the old caps marks the (+) positive lead rather than the negative end as on newer capacitors. I had to remove, test and reinstall every cap I replaced, since powering up a cap with wrong polarity can damage it. So, watch out for that too!
Great video. Thank You. I heard all of this repeatedly from the person I learned from. For instance: He insisted that I remove all glue before seating any new cap. It was a real pain, but he was an excellent tech, and I was lucky to learn from his extensive knowledge. What I learned from him served me well during my career (20yrs before retiring). BTW, You can also smell leaky caps as you heat. :-)
Great advice - particularly tip #2 i.e. not blindly trusting board markings and service manuals and tip #6 i.e. not replacing capacitors willy-nilly or all in one go. It's interesting you start with the problem of mistaking glue for capacitor leakage. However, old glue in some 80's-90's devices (particularly of Japanese origin but not exclusively) deteriorates and becomes corrosive with time and starts attacking the pcb and its tracks, damaging the pcb and causing problems. Going from left to right and from top to bottom in the screen, it looks like photos 3 and 4, with the brownish glue, are good candidates for investigating whether this is the case. If you suspect this glue is of that corrosive kind, you need to remove it scrupulously and clean the board afterwards with some appropriate solvent so there's no trace of the old glue left.
Just finished doing a complete recapp of an eBay purchased Philips 6731 tuner. I broke your last rule. I did the full recapp all at once. Plugged it in and NO SOUND! All the boards are easily removeable on this tuner with pins that plug into each board. After some troubleshooting I discovered a single pin/plug, that plugs into the RF board, had slipped down out of position (not making contact) So I applied some heat to the pin, in it's plastic housing, and slid it back into place. The unit now works absolutely fine. I think what happed is this unit uses 13 incandescent light bulbs inside (equivalent to 25 watts running inside the case!!! which I think caused the pin to slide out of position) I replaced all org. bulbs with LED. Fine sounding tuner!
Good advice. The only thins I would add are: a) the glue used to hold down capacitors in older equipment can sometimes be of a corrosive, very insidious type and needs to be thoroughly and meticulously removed to prevent damage to the circuit board b) at 8:05, I would not just say "beware of capacitors sold by sellers abroad" (whatever your country may be) I would just say "beware of capacitors of unknown provenance, sold by anyone without an impeccable reputation" as it may be the case that a seller may have bought capacitors from another seller and is just re-selling them without having ever tested them or checked where they actually came from--there's simply no guarantee of what you'll be getting then.
Note: you don't want to go a lot higher in voltage with electrolytics, as you run the risk of them not "forming" properly. Note that the fake restuffed "bumblebee" capacitor may well be more reliable than a genuine one.
I did enjoy this one. I never considered the glue being mistaken for leaky caps. I can see myself making that mistake even though I was aware some are glued. The last piece of advice is by far the most important though. This has bit me more than once in many different fields.
Lots of people think the glue is electrolyte leakage... And yes, marking things helps, but I use photos, lots of photos from lots of angles. That has saved my ass many times. lol!
I believe that 'glue' used to hold electrolytics and larger parts is normally known as 'staking adhesive' . It turns brown over time and is frequently mistaken for leaking electrolyte.
Most manufacturers of the electrolytic caps I have used recommend running them at 80% of the rated voltage to get the optimal life span. Read the data sheet on the electrolytic capacitor you are using as a replacement. Try to use exact replacements, otherwise you need to look at all the specs. ESR and surge and ripple current capability etc.
I as well have been in the TV service business for over 38 yrs, I agree COMPLETELY with everything you've said. Very good video. AND, all electrolytics are NOT the same, some are brand new with horrible ESR..!!
I see this a lot. Even units where the manufacturer has marked the board incorrectly, and fitted capacitors backwards because they followed the board markings!
Thanks you so much, You gave answers to a lot of questions I "had" before I watched this. I feel much more comfortable recapping my old Luxkit A3000 and A3032 after I watched this.
Same! I just finished recapping a TS-530S, and I checked each ones polarity as I pulled it out, just in case the marking on the board was buried somehow. But I never thought it could be wrong! I'll be marking my caps orientation before pulling them from now on!
While I don't work in the industry, I do electronic repair for myself. Marking the orientation is a great idea. I have removed caps only to then question the orientation on the board. I now mark orientation on everything I remove (for the most part).
Never seen your videos before, this popped up, I do a lot of vintage re-capping & I learned some good lessons here, especially the shotgun approach info :)
I really appreciate this video with the explanations and advices. I think every electronic technician should keep this in mind always to proceed any repair. I wrote all in my notebook! Thank you! Best Regards!
Great tips and the reason I watched this is I have a sansui 7 receiver like what you showed. Some day I may need to repair it but so far it still works great since the day I bought it in the mid 70’s. Thanks
Have you ever run across conductive glue? It's starting to happen in the top center pix at 1:18. The yellow glue turns brown and then starts to conduct. I don't know if it's the carbon in the glue or what but it starts to short out circuits. You can see it start to corrode the diode in the pix which may be a factor. I've fixed several units just by chipping the stuff off.
Measure for sure, also apply DC and 'form' the cap and check leakage and true capacitance after forming, of course discharge the cap before measuring again!
In some sensitive points of circuitry - specially in tape recorders of gramophone preamps value is also important. It is good idea to check real capacitance of new stuff - I found that of new 10pcs valuated at 10 uF no one reached 10 uF, some still in 10% tolerance but some were as low as 7,5 uF. While original ones 25 years old were opposite - above 10uF That can make quite a difference. Special care should be put to replacement of capacitors in speaker crossovers - producer tolerance is 10% so replacement without measurement usually will change sounding of set. Any change may be falsely interpreted as proof that old one had bad condition. Original one should be measured and , (in my opinion, if we tend to care for original timbre) value followed with accuracy 0,5% . It may be hard to match and proper way is to use smart combination of smaller values. Which will will not look original - that is why I would think twice before replacing crossover capacitors just for "idea".
I used to work at Audiotronics in No Hollywood, CA. They made indestructible record players and special purpose 7", 9" CRT video monitors for bank ATMs, etc. Pretty basic electronics. I serviced stuff that came off the assy line and failed initial plug-in test. Many were the days when Consuela on the assembly line installed C47 or D3 backwards and my repair consisted 47 record players or 29 little CRTs in a row with backwards diodes or caps. The funny thing was, on the CRTs, a backwards cap would typically explode and above the heads of the gals who didi initial plug-in, the aluminum backing of the roof insulation was peppered with holes from exploding caps that launched skywards. The only advantage was that there was no electronic knowledge req'd to fix these things, you could just see the part installed backwards. However, there were also some times when components were marked backwards and that could bend your brain.
Very good video. I am not a big fan of replacing blindly all caps in a older device. If the caps are good, they should not been replaced at all. A closer inspection and measurement of caps, can save time and money...
Great video! A few minor things though. One, take ESR into account - it can really matter. Two, voltage and capacitance can be interrelated and you won't know unless you read the datasheet for the part you are buying. For example many modern surface mount capacitors are rated capacitance at a fraction of their rated voltage, and actually have less capacitance at their full rated voltage, due to the physical properties of the high dielectric constant materials used today. So if you are changing from one chemistry or manufacturer to another in your replacement you really need to check the spec sheet for the new unit and ideally the old unit as well as the actual working voltage of the circuit. Three, your last rule of working in sections is a great point but I have one good counterexample. Tantalum capacitors. Their failure mode is particularly bad, rather than going open or losing capacitance like an aluminum electrolytic, they tend to short circuit. This has obvious serious effects on the rest of the circuit. I had one in a Tektronix oscilloscope power supply section short closed, explode, and splatter the entire power supply PCB around it with molten metal. Luckily it did not short any wiring on the board but it did fatally damage the bridge rectifier feeding it, which I only found out after the fact when it blew a fuse 20 seconds after I powered it back on after the recap. And 5 minutes after that, another tantalum capacitor failed in another area of the unit (a vertical amplifier board) which burned up a custom RFC I couldn't buy anywhere and had to rewind a replacement for myself. Ever since then, when I see one tantalum failure in a unit, I go in guns blazing and replace every single tantalum I can find. I may power the unit back up in stages and verify each board by itself if possible, but I'm not looking to troubleshoot three fires and 5 burned components after 2 capacitors shorted ever again.
I don't understand your point about capacitance and voltage being inter related. Surely, you identify the working voltage for the capacitor that you want to replace, and then replace it with a capacitor of the same or higher working voltage *and* the same value of capacitance. Isn't that what you do? What are you saying, the capacitance of the original capacitor depends on the DC voltage across it?
@@deang5622 that's actually exactly what I'm saying! I myself only learned this a few years ago, which is a bit embarrassing as I'm an EE. An older more experienced EE told me this back in 2017 and it seemed wrong so I read up on it and what do you know, it's actually correct. I seem to recall it's only on more exotic ceramic dielectrics used in modern MLCCs and some of the more modern dry electrolytic varieties such as niobium oxide, but give me a few minutes and I'll see if I can find the papers I read on the subject.
I enjoy watching blue glow videos. This man is no think he knows it all bone head like some on youtube & he doesn’t mind helping others. Some guys show videos of things that is impossible & will not work. Why those bone heads try to teach these things to newbies that could cause bodily harm to you is beyond me. Thank you Mark I think your name is. I watch your videos & they are very helpful. I just put transistors in a akai gx4000D . They was 2sc485 & I ordered 2sc1815y & I looked online & the 845 was EBC & I looked & it stated the 1815 was ECB & another page said EBC so I was lost. The seller of the 1815 said turn transistor facing opposite. Glad I didn’t I took a gamble & put it in like my gut said, EBC & it worked perfect. I told the seller, know what you sell & don’t gamble with my equipment or anyone else’s.
I might add that, when bodging in two 1000u in series because you want 500, dont assume that each capacitor will have half the voltage across it. Overrate the voltage or, possibly, add a couple of resistors to swamp leakage and so equalize the drops, (or you can order the correct component:)
loved the tip on not using the shotgun approach cuz that's the way i would have done my AV receiver... you may have saved me before i even got started !!!
Have a little care when using higher voltages capacitors, the ESR will go up. In a lot of circuits it will not matter, but in switching circuits it can be an issue.
Well done sir going to recap sansui au607d all points are very important before this video IAM fearing a lot now I got 70% confidence thanks for this Allah bless you
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
And the number 1 mistake... failing to pull out your cell phone and take a few pictures before you start pulling out capacitors.
😂😂😂
Damn this is so true. And one step up, take a video with good lighting of various angles. I’ve saved myself so many times.
@@XJ290 video thing is even better with different angles, i also do it now.
@@deepaknanda1113100%. You can find just the right frame that shows where something goes or how it was oriented.
True n necessary for future reference 👍
"Trust what's on the board not what's in the manual..." Ha yes! I write code for a living. One of the first things they taught us was it maters what the computer does - not what the manual says. Great video thanks for posting it!!
As a retired electronics tech I can say that this is good advice.
I've subscribed because your video is clear & succinct and not padded out to 30 mins like many others do.
here-here!
Hear, hear!
Love the "Recap one section at a time" advice. As much as it sounds like a simple and easy thing to do, I was many times tempted to just keep going (for 5-6 hours ) . It is a very good advice so ty.
If you have a 1930's radio with old dripping wax capacitors and electrolytics and it don't power up. I fail to see how doing a section at a time helps. If your radio was working, why are you recapping? Thoughts?
@@jameshochstetler4808When doing a "recap job," you may be "fixing what isn't broke." That's why.
Great advice!! I'm guilty of the shotgun approach because I wanted to listen to my vintage receiver right away. More than once, I spent more time trying to figure out where I went wrong with my DMM, hooking up my DBT, reading voltage/current values through everything and trying to read the blurry values from a scanned service manual, playing the AM/FM tuner, hooking up a turntable and using the phono/EQ board, etc. etc. You get the idea.
Take your time. Do one section at a time, and then test your receiver. Another piece of advice is pay attention to the orientation of new transistors vs. old ones. Some older transistors tend to have EBC instead of a more modern ECB.
Great video and full of info. Had VCR many years ago with Alzheimer's. Sometimes responded to controls sometimes not. After hours of troubleshooting and consultation with others in the biz, turned out it was an adhesive foam pad (several) on bottom of circuit board between it and metal bottom of machine. After removing pads found affected traces in different states of degradation . The adhesive had eaten into traces and was semi-conducting between them, thus the Alzheimer's symptoms. No clue until pads actually removed to see damage. Rock solid after repair. Do not underestimate any "material" on a board to cause trouble.
Two important issues when recapping with a higher value; 1. never do this with starting capacitors in motors, they need the exact right value. 2. Recapping with a much larger value in a power supply can cause damage to the bridge rectifier, because the current peak when staring up, is much higher then.
An other important issue is the temperature which is mentioned on the capacitor. The switching power supplies before the 1990's often used capacitors, marked with 85°C. This was also one of the reasons of the caused problems. Always use 105°C capacitors for switching power supplies!
Not me who learned every one of these the hard way over the years..
Or higher if you can find them. Capacitor temp rating directly informs capacitor life, even if the ambient isn't very warm.
By value, you mean capacitance. You can use starting caps with a higher voltage rating.
Nice to hear someone talk electronics. September of 80s when I started working electronics. Who was the best thing that could have happened to me. I still use my skills on fixing vintage cars. I can handle anything electronic. I'm an expert digital troubleshooter. I operated on oscilloscope and a digital voltmeter like nobody else. This is no joke, I literally show this guy that with my hand over the board I could find the problem. He went to get the chipper placed and he wants to know how I did that. That man had three days working on that card. I still do stupid stuff like that. I love having a witness around see the things that I do.
What's nice about troubleshooting stereo equipment is that the channel that is in good working order can be a good reference for measurement comparisons. Hard to find problematic components can be detected this way. Just make sure that your reference input signals are exactly the same for the left and right channels. An oscilloscope can also be an excellent visual aid to compare for abnormalities in the defective channel.
I order my caps from Mouser because 1. they typically have good prices, 2. they usually have what im looking for and in stock and 3. I order over the phone to do Will-Call because I live about 20 minutes from the warehouse and I can typically have my Caps the same day or next day and avoid the shipping charge altogether.
Who is Will Call?
If you're recaping really old stuff (20's and 30's era), capacitors had a lot of internal conductance that was accounted for in the original circuit that new capacitors don't have. You may need to add a resistor in parallel to keep the circuit 'in tune', and guessing the size of that resistor is really just a guess.
That's what I did when I reccaped my Victor RE-45. It works amazing. That's a very good advice for people who don't know.
Interesting 😮
Like add ESR to the cap. The wire wound resistor has some series inductance to.
Are there existing types of capacitors that may be more appropriate for this usage?
I recently replaced the electrolytic capacitors in a GE digital tuned clock radio from the late 1970s or early ‘80s which was too nice to throw out. Being on for 40 years 24x7 took its toll. The symptoms were erratic operation such as the alarm beep going off at random times and poor audio quality. As I pulled the capacitors, I checked them with an M Cubed Electonix impedance bridge and found about 1/4 of the capacitors had only about 1/3 their rated capacitance. Quite a few capacitors had also developed unreasonably high effective series resistance, as much as 30+ Ohms.
After my order for capacitors of the same proper values and withstand voltages arrived from Digikey, it took a few hours to swap all the electrolytic capacitors. Since there were so many off value parts, I decided to replace all of the aluminum electrolytic capacitors so that I would not have to go back to replace more parts later. After a few hours of patient work, everything was good to go and the radio sounds great again. If you follow the advice in this video you’ll almost certainly have a good outcome with more life from your old equipment.
I just learnt so much from this short clip. I just dismantled a 1970s JVC amp to repair. I’m so glad I haven’t started on removing parts.
From someone who has rebuilt vintage electronics this video is EXCELLENT. Every new electronics tech should see this video.
#BIGFACTS & #2Thumbs&BigToes^UP^
Thank you.
Not "Good Stuff". This is "GREAT STUFF". Informative, concise and pragmatic. Bravo Sir!
One thing I would add, having worked on computer monitors in the past ( 25 years ago) some brands had that hold down glue that would over time become unstable from heat and age and become conductive on the board. We had to scrape it all off and clean the board really well.
AKA, Sony Bond. It affects all kinds of electronics. If it starts to turn dark brown or darker, get it off the board.
That's a great point.!!, I too have seen glue become conductive and cause many problems in TV's.
lol yeah the white glue is okay most of the time, but that transparent stuff is nasty.
Another fun one are those fancy looking motherboards with chipset coolers that have stickers/decals on them... those come loose over time because of heat and get trapped in the fans.
KRK monitors had some black stuff where the liquid would seep out and cause corrosion, the rest of the glue became brittle. Have to remove that and hopefully before components are so wrecked you can;t even see what they were
@@Joetechlincolns is that still common? Thanks
"Smooth, rounded, flow. Smooth, rounded, flow. Smooth, flowing, stuff." I meditated and achieved internal peace there, what a voice! :D
My expectations were low when I started this video, I was expecting "don't reverse the polarity of electrolytic capacitors" and "make sure the foil end of the capacitor is connected the ground side", neither of these points were covered, instead all the tips were fresh and thought provoking. Very enjoyable!
Awesome tips! #6 is priceless. Thanks for the QUICK, to-the-point and absolutely helpful video. NEW FAN!
I thought I was pretty foolproof in identifying component glue, but in your example picture I would've been convinced that the upper right and lower left pics were leaked electrolite.
I work in electronics and am working on getting into restoring (and in some cases modernizing) antique radios as a hobby, so videos like these have been good for picking up on stuff I wouldn't have realized right away with vintage stuff. Great video.
This video is excellent, your methodology is all common sense for anyone experienced in servicing electronics. However, when it comes to factory glue, even if you can still identify it correctly, you must remain cautious and always observe precautionary. Some of these glues have proven corrosive or decompose in corrosive material, so if you notice oxidized copper tracks, rotten component legs, you'll probably have to remove that goo, restore PCB and probably change all components touched, resistors and semiconductors. Leaky caps can also smell badly: most of leaky SMD electrolytic capacitors include a fish oil impregnating everything.
And here is also an important point, most quality electrolytics can still work fine after years if used and stored in proper condition. You also need specific equipment to check and test if they really need some replacement: you should measure values and ESR, and for specific uses like high voltage ones, a specific leakage test has to be performed. Of course, with experience or proper documentation, you have a number of specific condensers you will systematically change in 100% of equipment, mostly because their replacement is critical and always cheaper than the component they protect, like high voltage decoupling caps in tube electronics.
And when it comes to components locations or sense, wiring and so, it's also interesting to take a number or pictures and notes along markings.
Rule number one is to take the necessary time to observe and analyse any further action.
A possible exception to your suggestion against "shotgun" recapping is when restoring very old equipment. 50 or 60 year old electrolytics are often shorted, or nearly so. Turning on the equipment with such caps in the power supply can cause serious damage. The same applies to interstage coupling caps in tube amplifiers. If those are electrically leaky, B+ will flow to the grid of the next stage and that is also damaging.
I shot gun the caps in my vintage repairs. These caps are 40+ years old and way past their lifetime expectancy. And for s**ts and grins, I 'll use my ESR which says "yep.. it's fine" and use my old Heathkit leakage checker. 80% of the "good" caps fail leakage tests. The exception to this rant seems to be the smaller electrolyics normally used in the radio RX boards for example. Most of those I replace with WIMA anyways.. I hate having to redo my work. And fixing a unit just to have a ancient cap fail a few laters is stupid. I also replace driver transistors for the same reason. You have no idea how abused they are so I just replace them since I already have the unit apart on the bench. Zeners go to for the same reason. Carbon resistors in amplifier boards get replaced because most of drifted a fair bit and will continue to drift as they age even more. And I should say, I don't "repair" my projects.. I "restore" or "rebuild" them.. just like a car. And lets be clear.. this is my opinion.. nothing more. Everyone is entitled to their own opinion. My clients are happy with mine and how I do the work :)
@@MikeSweeneyMedia , Yeah, if you have to undo the dial string mechanism in order to pull up the RF, IF, and/ or MPX board (often those circuits are combined on one single long PC board), you want to be really certain that recapping is done with known good caps, and that you fix any problems or potential problems before you put the whole shebang back together.
I see your point. His advice is good if you are recapping something that works already.
Yes, better to replace the electrolytic and paper caps than destroying transformers and such that are made of "unobtainium" now. I do the same on old tube stuff.
Oh definitely, old caps can short out. So can small smd ceramic caps if they develop a micro fracture from mechanical stress.
I particularly liked the point that there are factory mistakes as I have found several over the years but did not know about mistakes in service manuals nor was I aware of silk screen mistakes on circuit boards. Thanks for the info.
Great video with lots of good points. I would caution about using a replacement electrolitic capacitors
with with a voltage a lot higher then the original. Such as putting a 350 volt in place of a 25 volt because it won't stay properly formed with the lower working voltage.
While it is not in the scope of this video, all that glue on those circuit boards, that some over time degrades and becomes caustic and conductive. As long as you are replacing the capacitors, you should remove the glue as well. Once again this is a great video, keep them coming when you can, stay safe and have a wonderful holidays.
yep, dont go too higher in voltage , and yes some types of glue definitely cause trouble, in some cases causes corrosion and track or wire damage
Tremendous waste of money too......if you could even squeeze it in.
Yes, I remember years ago reading that too high a voltage isn't good for use at much lower voltages.
Yep, and there is something else to consider too. E.g. with modern switching power supplies, ESR (=equivalent series resistance) is important. Higher voltage caps have higher ESR than lower voltage one with same capacity, which is a bad thing. So, going a little higher may be ok, but not much higher.
Thank you for putting the time into this video and helping keep us all safe.
Excellent video! Always good to hear from techs from the good old vacuum days when things were made in the good old USA and everyone was employed. Sylvania, Westinghouse, General Electric, Magnavox, Panasonic, Admiral and many more. In contrast to present day times, I treasure those days. Thanks for sharing.
@Andrew_koala I agree with your comments on lower shipping fees from the US. I see many excellent US products new and second hand. However the shipping costs for customers in Australia can sometimes be quite a bit more than the goods themselves .. A real shame actually. I have one or two old pieces of test equipment made entirely in the US. They are very satisfying to use. Thanks for voicing some interesting thoughts.😁
Panasonic? was and is part of the Matsushita corporation of Japan. That said, it's been a trading name of Matsushita since forever.
Great video, with many good points raised. Re: not trusting board markings. There's at least one infamous example in the computer world: one revision of the Sinclair ZX Spectrum shows incorrect polarity markings for one of its capacitors, which has caught many people out over the years (resulting in many dead ZX Spectrums in the process).
As for marking capacitors i.e. the "measure twice cut once" tip, taking clear high res photos of the board you're about to work on _prior_ to starting on it is also a very good idea IMHO.
Nice video! I use to snap a bunch of pictures of the PCBA before I start working. Nice way to keep track of orientations, values, and such. It has saved me a few times with bad PCB polarity markings as you showed here.
Thumps up
Often I take pictures with my wirless phone.
And every time I mark the capacitor (and the orientation from connectors).
I use often diffenrent colours.
I mark capacitors on top and at the PCB with a small dot.
That glue when it turns brown, instead of yellow, is actually CONDUCTIVE. Especially if it is near something that is starting to corrode. I've fixed many malfunctioning electronics just by chipping that glue off. When it turns brown it becomes brittle facilitating this.
In the past I had resolved CPU problems as well due to the heat sink compound getting on the CPU pins or on the visible CPU circuit. Wiped off the compound on those pins or other contact points and the computer worked fine then..
It next turns corrosive and eats the legs off components it’s in contact with.
@@porkchop3656 Yes acid (or caustic soda or other)
EXCELLENT VIDEO. Thanks. I am working on a little sound board of a 1970 arcade game that uses electro-mechanical pinball technology. Even a little sound board that only makes three sounds has 6 transistors and 37 capacitors. Half electrolytics and half "tropical fish."
Great tips, excellent video. Even guys that work on equipment regularly can get benefit from watching this. I learned something here thank you.
Very well-done vid...no fancy lights or annoying background music...thanks! I really liked #6!
Awesome advice. Hate to say some of these mistakes are already in my inventory.
Well spoken!
All really great advice, re-capping is a great way to generate tears of frustration if you do it willy-nilly. I would only bother if the gear has a real problem.
These are the types of videos that help me the most. That cover all types of electronics not just radios and such.
I repair vintage and modern electronics, mostly test equipment and industrial electronics. A lot of motor drives, PLCs, and a lot of automation control equipment. I do see a lot of 1980s equipment that is still in service so I recap and repair a lot of stuff like that… And these are the videos that help me the most. Although I do enjoy radio repair, I don’t do it very often so these general subject videos that cover a broader range of electronics are extremely helpful!
All good advice. A short version of the quality points, don't be cheap! Mouser, Digi-Key, even over the counter, if it's still an option for you, is better for jobs like these. How much is your time worth? How much is the gear to be repaired worth? How important is your success rate worth to your business? Spend $2 for one instead of the bag of 100 for $5 online. I worked at a place many decades ago that had a sign: If you don't have time to do it right, do you have time to do it again?
I am preparing to do some repairs on my Tascam M-30 and Teac Model 5 mixers. This is a great list of things to know and I'm grateful to learn these tips before I dive in.
Good video. Never thought about marking the tops of caps ... good idea!
neither do I .. very good one ...
Number tops of caps 1, 2,3.. etc, in order, now you know polarity and position after removing from circuit.
I take lots of photos too. Your cell phone camera can be a real friend here. ;-)
I am a retired electronics engineer and HAM radio operator. I worked in many different types of design disciplines . I also restore equipment. I am aware of all you presented and I love my subscription to your channel. I watched this one and am impressed how well you presented these common mistakes. I have friends that shotgun and who mistake the wave-flow or retention glue for leaking capacitors. In tube circuits friends with guitar amps typically want to up the capacitance which has caused them many problems. I am trying to work with them and they say I'm a perfectionist or taking too technical of an approach. These same folks do not embrace ohms law and also try to check caps and other components in circuit with a Ohm meter in diode mode. Sheesh.... I'm trying to teach them, but I will pass your video along to them. Thank you so much ! I am currently designing my own Class A and AB1 amplifiers, All tube and Hybrids and you have helped me immensely as designing tube equipment is much different than servicing Them. Thanks Again !
Seems to me that you are out of their leagues, to put it mildly.
Your videos are fantastic! I have a professional lounge organ; a Wurlitzer 805, built around 1975. The voices haven't worked properly in years, and I have come to learn that the power supply and switching boards are the prime suspects. I thought I would have to replace the capacitors with the exact same parts, which I was trying to at least find a source for before I started disconnecting and testing. The search was unsuccessful! Your video gave me confidence that I can restore whatever caps these boards need by following the tips and procedures you showed. Thank you for loads of valuable information!
Excellently done and very much appreciated. Helps restore my faith in mankind. Thank you.
This was clear, succinct, and above all helpful. Thank you.
This video content is excellent. What you covered in 10 minutes took me 10 or more years to stumble across as a circuit designer. This video is a keeper and a "must see" video for anyone with a soldering iron. Thanks Mark.
Just the tip on marking the orientations on the tops was worth the whole video!... lots of great tips..... Thanks!
Thanks for the flag up on the potential issues with board markings and service manuals. I've come across it myself, so what I always do is photograph what I'm about to remove and always refer back to the photo when I'm replacing.
I have been working on vintage electronics for most my 60 years. and your video did make me think of a few things I had not considered.
I often take a photo of boards to use as reference when recapping etc.
Often a wire might break from moving things around and you are scratching your head where it came from.. And recently it came up that going too high in capacitance and voltage even in a power supply can be a mistake.. filter design depend also on resitance and inductance loads.. and even a supply is partly a filter.
Very useful video! I need to recap the crossovers in my 1970's Technics speakers and this video will be a handy reference.
I've also experienced improper markings on Marantz gear. Very good advice for all techs. Thank you.
It is really valuable author' advice with markings. Simple and clear. Also not bad idea today is to make sharp photo of board (with flash) with parts and connections in original placement. And to study original schematic for tracing damages - this saves unnecessary replacements which do not help and degrade overall condition .
i'm glad i watched this before recapping any vintage electronics.
Thanks to made this video , I usually recap 70’s amp & Receivers
This can be great information for who want to recap in first time 👍👍
When I derate caps on a recap job I usually derate on the next voltage up, no more. I always test new caps, you never know. I always test the caps coming out as a learning experience. Good video.
One more, I usually recap no more then four caps then do an operation check. Just in case you have back track.
@@philhemenway3503 not a bad idea, but depending on how hard it is to access the boards or get them back into circuit, that could really add up in time lost! One section at a time seems reasonable compromise
Great suggestion, but my Q is: how do you test capacitors?
@@CycloneCyd There are many cap meters avaiable or your DVM may have a cap measuring capability.
This is a good approach, for a few reasons. First, the electrolytic capacitors can lose their "forming" as the oxide which is the actual dielectric is created maintained by applying a DC voltage across the capacitor. So a capacitor rated for a much higher voltage may age faster with little voltage applied to it.
Secondly, the next person who replaces the same capacitor is even less likely than you to have the schematic for the device, as it becomes more obsolete and forgotten about in the future. So they will also see the voltage shown on the capacitor as the minimum value it should have, and possibly increase it. They most likely won't reverse engineer the circuit unless it still doesn't work after the recapping. This can eventually lead to a ridiculous voltage rating that raises the cost of the repair.
Great tips, 100% agree. I'd add 'use some respect when soldering'. Easy to damage tracks on *certain* boards.
@Rosetta Stoned Yah only being doing this for 40 yrs. Share your wisdom please :)
Very good info. Some I knew, some I didn’t. Thanks for sharing!
I think your video is great and useful because a lot of electronic related video on the internet does and suggest very bad advice that create more confusion than clarification.
Very informative video not only for newbies but for experienced ones too. Great guide. Love you man and thanks.
Glad I caught this, recapping some old stuff, soon a 70's Pioneer, this is going to save me some head aches.
Wonderful! Back 2 Basics will never go out of style. Thank you
thanks for the insight of your experience, no wonder i followed through my amplifier’s service manual , even looking at the board themselves, and just to fry out poping my capacitors eventhough i believed i had done everything correctly. As much as i love my amplifier, taken extra care and steps , sometimes things happens.
At 00:55, The top-left CAPs have that rubbery glue to stop the component from vibration, (i.e.) subwoofer cabinet.
Remember the era when people used to mount their amplifier directly on the subwoofer box itself? LOL
I made a lot of easy money repairing amps because the vibration had shaken loose anything heavy or tall. XD
(the amps were usually mounted sideways)
On an old R-R tape recorder that I recapped recently, the electrolytic caps had a stripe on the side to indicate polarity. Unfortunately, as I discovered after replacing many capacitors, the stripe on the old caps marks the (+) positive lead rather than the negative end as on newer capacitors. I had to remove, test and reinstall every cap I replaced, since powering up a cap with wrong polarity can damage it. So, watch out for that too!
Good point! I've seen this too on older Toa amps!
I once encountered an LED which had the flat marking on the positive lead. It should be on the negative lead. I was so confused.
Diode: mismarked; ☺1 in thousands; thank God I cheched 'em all!
@@PunakiviAddikti yep, i have some like that, you must never assume the polarity, double check
wrongly polarized caps make nice fireworks , ask me how i know..
Great video. Thank You.
I heard all of this repeatedly from the person I learned from. For instance: He insisted that I remove all glue before seating any new cap. It was a real pain, but he was an excellent tech, and I was lucky to learn from his extensive knowledge. What I learned from him served me well during my career (20yrs before retiring).
BTW, You can also smell leaky caps as you heat. :-)
mmmm that weird fishy smell :)
Great advice - particularly tip #2 i.e. not blindly trusting board markings and service manuals and tip #6 i.e. not replacing capacitors willy-nilly or all in one go.
It's interesting you start with the problem of mistaking glue for capacitor leakage. However, old glue in some 80's-90's devices (particularly of Japanese origin but not exclusively) deteriorates and becomes corrosive with time and starts attacking the pcb and its tracks, damaging the pcb and causing problems. Going from left to right and from top to bottom in the screen, it looks like photos 3 and 4, with the brownish glue, are good candidates for investigating whether this is the case. If you suspect this glue is of that corrosive kind, you need to remove it scrupulously and clean the board afterwards with some appropriate solvent so there's no trace of the old glue left.
Just finished doing a complete recapp of an eBay purchased Philips 6731 tuner. I broke your last rule. I did the full recapp all at once. Plugged it in and NO SOUND! All the boards are easily removeable on this tuner with pins that plug into each board. After some troubleshooting I discovered a single pin/plug, that plugs into the RF board, had slipped down out of position (not making contact) So I applied some heat to the pin, in it's plastic housing, and slid it back into place. The unit now works absolutely fine. I think what happed is this unit uses 13 incandescent light bulbs inside (equivalent to 25 watts running inside the case!!! which I think caused the pin to slide out of position) I replaced all org. bulbs with LED. Fine sounding tuner!
Good advice. The only thins I would add are:
a) the glue used to hold down capacitors in older equipment can sometimes be of a corrosive, very insidious type and needs to be thoroughly and meticulously removed to prevent damage to the circuit board
b) at 8:05, I would not just say "beware of capacitors sold by sellers abroad" (whatever your country may be) I would just say "beware of capacitors of unknown provenance, sold by anyone without an impeccable reputation" as it may be the case that a seller may have bought capacitors from another seller and is just re-selling them without having ever tested them or checked where they actually came from--there's simply no guarantee of what you'll be getting then.
Is this your first time thinking about replacing components in your speakers? Then this is a great video.
Note: you don't want to go a lot higher in voltage with electrolytics, as you run the risk of them not "forming" properly. Note that the fake restuffed "bumblebee" capacitor may well be more reliable than a genuine one.
Yes, in addition to that the higher the voltage rating the higher the ESR.
Excellent tips! Mismarked boards...had my first exciting sizzle...pop! on a power supply board that was mismarked.
This is a really great video!
Thank you. It comes from someone that has a lot of experience, and I appreciate you sharing your knowledge.
Thank you!
I did enjoy this one. I never considered the glue being mistaken for leaky caps. I can see myself making that mistake even though I was aware some are glued. The last piece of advice is by far the most important though. This has bit me more than once in many different fields.
Lots of people think the glue is electrolyte leakage... And yes, marking things helps, but I use photos, lots of photos from lots of angles. That has saved my ass many times. lol!
I believe that 'glue' used to hold electrolytics and larger parts is normally known as 'staking adhesive' . It turns brown over time and is frequently mistaken for leaking electrolyte.
Most manufacturers of the electrolytic caps I have used recommend running them at 80% of the rated voltage to get the optimal life span. Read the data sheet on the electrolytic capacitor you are using as a replacement. Try to use exact replacements, otherwise you need to look at all the specs. ESR and surge and ripple current capability etc.
45 years as a professional service tech for the big guys here,... all very good advice.
Nice video. Seeing gear with surface mount PCBs considered “vintage” makes me feel old.
Yeah, I hear ya. 😥
Good information and much appreciated.
I as well have been in the TV service business for over 38 yrs, I agree COMPLETELY with everything you've said.
Very good video.
AND, all electrolytics are NOT the same, some are brand new with horrible ESR..!!
many modern capacitors are crap
Great point about the boards and schematics being marked wrong!!!!
I see this a lot. Even units where the manufacturer has marked the board incorrectly, and fitted capacitors backwards because they followed the board markings!
Very good advice here ! especially the last segment... and the orientation marking. great stuff !
Thanks you so much, You gave answers to a lot of questions I "had" before I watched this. I feel much more comfortable recapping my old Luxkit A3000 and A3032 after I watched this.
Very good info from years of experience! The best kind. Thank you. You have brought to mind things I wouldn't have thought of until after.
This is great advice. I definitely see these same issues when recapping. Thanks for putting this out there!
The tip on wrongly printed polarity was new to me, thanks for that 👍
Same! I just finished recapping a TS-530S, and I checked each ones polarity as I pulled it out, just in case the marking on the board was buried somehow. But I never thought it could be wrong! I'll be marking my caps orientation before pulling them from now on!
While I don't work in the industry, I do electronic repair for myself. Marking the orientation is a great idea. I have removed caps only to then question the orientation on the board. I now mark orientation on everything I remove (for the most part).
Great video. Will help save time and a lot of money. Thank you. Greetings from the Philippines
Never seen your videos before, this popped up, I do a lot of vintage re-capping & I learned some good lessons here, especially the shotgun approach info :)
Right? That tip alone was firmly worth the time for the vid. It's deceptively obvious now, but I can imagine falling into the trap otherwise!
I really appreciate this video with the explanations and advices. I think every electronic technician should keep this in mind always to proceed any repair. I wrote all in my notebook! Thank you! Best Regards!
Great tips and the reason I watched this is I have a sansui 7 receiver like what you showed. Some day I may need to repair it but so far it still works great since the day I bought it in the mid 70’s. Thanks
Have you ever run across conductive glue? It's starting to happen in the top center pix at 1:18. The yellow glue turns brown and then starts to conduct. I don't know if it's the carbon in the glue or what but it starts to short out circuits. You can see it start to corrode the diode in the pix which may be a factor. I've fixed several units just by chipping the stuff off.
i have a few times...
Test the new ones before soldering them in,there might be a faulty one...
if you have the instrument, the right one, its an excellent idea ....
@@eloyex yes,a tester is always handy,not too expensive nowadays,made in China ofcourse
Measure for sure, also apply DC and 'form' the cap and check leakage and true capacitance after forming, of course discharge the cap before measuring again!
@@mmpiforall5913 If you're concerned that your new cap might be open, plug it into mains and see if it explodes. If so, it was good ;-)
In some sensitive points of circuitry - specially in tape recorders of gramophone preamps value is also important. It is good idea to check real capacitance of new stuff - I found that of new 10pcs valuated at 10 uF no one reached 10 uF, some still in 10% tolerance but some were as low as 7,5 uF. While original ones 25 years old were opposite - above 10uF That can make quite a difference. Special care should be put to replacement of capacitors in speaker crossovers - producer tolerance is 10% so replacement without measurement usually will change sounding of set. Any change may be falsely interpreted as proof that old one had bad condition. Original one should be measured and , (in my opinion, if we tend to care for original timbre) value followed with accuracy 0,5% . It may be hard to match and proper way is to use smart combination of smaller values. Which will will not look original - that is why I would think twice before replacing crossover capacitors just for "idea".
I used to work at Audiotronics in No Hollywood, CA. They made indestructible record players and special purpose 7", 9" CRT video monitors for bank ATMs, etc. Pretty basic electronics. I serviced stuff that came off the assy line and failed initial plug-in test. Many were the days when Consuela on the assembly line installed C47 or D3 backwards and my repair consisted 47 record players or 29 little CRTs in a row with backwards diodes or caps. The funny thing was, on the CRTs, a backwards cap would typically explode and above the heads of the gals who didi initial plug-in, the aluminum backing of the roof insulation was peppered with holes from exploding caps that launched skywards. The only advantage was that there was no electronic knowledge req'd to fix these things, you could just see the part installed backwards. However, there were also some times when components were marked backwards and that could bend your brain.
Very good video. I am not a big fan of replacing blindly all caps in a older device. If the caps are good, they should not been replaced at all. A closer inspection and measurement of caps, can save time and money...
This was an awesome video. Thanks for teaching us!
Marking position referenced to the front of the board is the best tip, because it is so difficult to screw up!
Thank you sir. Excellent video and tips especially taking the one section at a time approach.
Well,... you can teach an old dog new tricks. I just learned something new today. Excellent informative video!! Thank you.
Great video! A few minor things though. One, take ESR into account - it can really matter. Two, voltage and capacitance can be interrelated and you won't know unless you read the datasheet for the part you are buying. For example many modern surface mount capacitors are rated capacitance at a fraction of their rated voltage, and actually have less capacitance at their full rated voltage, due to the physical properties of the high dielectric constant materials used today. So if you are changing from one chemistry or manufacturer to another in your replacement you really need to check the spec sheet for the new unit and ideally the old unit as well as the actual working voltage of the circuit. Three, your last rule of working in sections is a great point but I have one good counterexample. Tantalum capacitors. Their failure mode is particularly bad, rather than going open or losing capacitance like an aluminum electrolytic, they tend to short circuit. This has obvious serious effects on the rest of the circuit. I had one in a Tektronix oscilloscope power supply section short closed, explode, and splatter the entire power supply PCB around it with molten metal. Luckily it did not short any wiring on the board but it did fatally damage the bridge rectifier feeding it, which I only found out after the fact when it blew a fuse 20 seconds after I powered it back on after the recap. And 5 minutes after that, another tantalum capacitor failed in another area of the unit (a vertical amplifier board) which burned up a custom RFC I couldn't buy anywhere and had to rewind a replacement for myself. Ever since then, when I see one tantalum failure in a unit, I go in guns blazing and replace every single tantalum I can find. I may power the unit back up in stages and verify each board by itself if possible, but I'm not looking to troubleshoot three fires and 5 burned components after 2 capacitors shorted ever again.
I don't understand your point about capacitance and voltage being inter related.
Surely, you identify the working voltage for the capacitor that you want to replace, and then replace it with a capacitor of the same or higher working voltage *and* the same value of capacitance. Isn't that what you do?
What are you saying, the capacitance of the original capacitor depends on the DC voltage across it?
@@deang5622 that's actually exactly what I'm saying! I myself only learned this a few years ago, which is a bit embarrassing as I'm an EE. An older more experienced EE told me this back in 2017 and it seemed wrong so I read up on it and what do you know, it's actually correct. I seem to recall it's only on more exotic ceramic dielectrics used in modern MLCCs and some of the more modern dry electrolytic varieties such as niobium oxide, but give me a few minutes and I'll see if I can find the papers I read on the subject.
I enjoy watching blue glow videos. This man is no think he knows it all bone head like some on youtube & he doesn’t mind helping others. Some guys show videos of things that is impossible & will not work. Why those bone heads try to teach these things to newbies that could cause bodily harm to you is beyond me. Thank you Mark I think your name is. I watch your videos & they are very helpful. I just put transistors in a akai gx4000D . They was 2sc485 & I ordered 2sc1815y & I looked online & the 845 was EBC & I looked & it stated the 1815 was ECB & another page said EBC so I was lost. The seller of the 1815 said turn transistor facing opposite. Glad I didn’t I took a gamble & put it in like my gut said, EBC & it worked perfect. I told the seller, know what you sell & don’t gamble with my equipment or anyone else’s.
I might add that, when bodging in two 1000u in series because you want 500, dont assume that each capacitor will have half the voltage across it. Overrate the voltage or, possibly, add a couple of resistors to swamp leakage and so equalize the drops, (or you can order the correct component:)
loved the tip on not using the shotgun approach cuz that's the way i would have done my AV receiver... you may have saved me before i even got started !!!
Have a little care when using higher voltages capacitors, the ESR will go up. In a lot of circuits it will not matter, but in switching circuits it can be an issue.
Well done sir going to recap sansui au607d all points are very important before this video IAM fearing a lot now I got 70% confidence thanks for this Allah bless you
Very vital information when replacing caps.in vintage equipment.
Thank you
Well I never you can teach old dogs but you learn something different every day and time thanks