Six Common Mistakes Made When Recapping Vintage Electronics
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- เผยแพร่เมื่อ 6 มิ.ย. 2024
- Short little video on common mistakes seen when recapping (replacing capacitors) vintage electronics. This would include vintage stereos, radios, equipment, CBs, ham radio receivers & transmitters, calculators, computers, you name it.
Hopefully this will provide you some tips and hints to use when you go to recap your piece of vintage gear.
Topics include:
- Mistaking Factory Glue for Leaking Capacitors
- Factory Boards and Manuals Marked Wrong
- Capacitors Installed Incorrectly
- Using Larger Capacitors Than Specified
- Buying Electrolytic Capacitors off Ebay
- Replacing Everything at Once - วิทยาศาสตร์และเทคโนโลยี
And the number 1 mistake... failing to pull out your cell phone and take a few pictures before you start pulling out capacitors.
Didnt make that mistake with caps on an old valve amp, but i did with the resistors, both photos and thinking 70 year old resistors have same tolerances as new stock. Caps worked well an improved operation. I destroyed the project by replacing resistors...😢 (only a hobbist, not classically trained)
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.
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 video. Seeing gear with surface mount PCBs considered “vintage” makes me feel old.
"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!!
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 😮
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.
Not "Good Stuff". This is "GREAT STUFF". Informative, concise and pragmatic. Bravo Sir!
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.
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
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)
Thank you for putting the time into this video and helping keep us all safe.
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.
This is great advice. I definitely see these same issues when recapping. Thanks for putting this out there!
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.
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!
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.
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 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.
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.
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.
From someone who has rebuilt vintage electronics this video is EXCELLENT. Every new electronics tech should see this video.
#BIGFACTS & #2Thumbs&BigToes^UP^
"Smooth, rounded, flow. Smooth, rounded, flow. Smooth, flowing, stuff." I meditated and achieved internal peace there, what a voice! :D
Great tips, excellent video. Even guys that work on equipment regularly can get benefit from watching this. I learned something here thank you.
Wonderful! Back 2 Basics will never go out of style. Thank you
This video is great, common sense and we'll worth watching! That shotgun tip is solid gold, I kind of had that one worked out already but to have it confirmed by an expert is really satisfying, the same for the rest of this excellent video...thanks!
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.
Good info...as always. Been needing to recap the power supply of my cassette deck. So very helpful.
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 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!
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.
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.
Excellent presentation. I learned a lot. Thank you!
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.
Great common sense info. I got caught on the last item in your list when I recapped a Hallicrafters s-86. Won’t happen again! Thanks for producing videos like this one. I enjoy your channel very much.
excellent video! I am learning as I go and your videos are very helpful! Thanks for your efforts and contribution to the hobby!
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.
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
Wonderful message it will save time and patience. Thank you
Excellent video. Lots of stuff there I hadn't considered before. Good point about the board errors.
Fabulous advice, very informative & interesting, thanks.
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 .
Nice tips; the last one indeed is the best. Regarding polarity mistakes, I've seen once one board with some pen corrections.
Learning this for vintage studio equipment. THANKS
Thank you sir. Excellent video and tips especially taking the one section at a time approach.
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 👍👍
Very vital information when replacing caps.in vintage equipment.
Thank you
Same as Storm 1 below - your video just popped up, but I'm glad it did as I found your video to be very informative and interesting - thankyou for posting it
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.
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.
Just the tip on marking the orientations on the tops was worth the whole video!... lots of great tips..... Thanks!
Outstanding advice, my friend.
Awesome tips Sir!!! Thank you very much
Awesome tips, especially the one on the shotgun approach. Thank you!
Some great points to take into consideration. Thanks for the video.
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.
Incredible vid. Thanks for sharing your wisdom
Good information and much appreciated.
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.
Great advice. Very enlightening. Thanks for sharing the information!
Great advise !! Outstanding video !! Thank You
I leaned a few tips from your video. Thanks.
man these are awesome tips!! i'm subscribing to this channel so freaking hard. thanks man
Great video. Will help save time and a lot of money. Thank you. Greetings from the Philippines
That was my post you featured in relation to the Sansui 9090 power supply polarity markings in the video, pretty cool, Thanks! 😎👍
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!
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!
Nice to see this! Many defend that a recap should always be done, regardless.
Great video man. Love your channel. Regards from Ireland
Good tips -- especially the last one!
Great advice, thanks for sharing!
Outstanding video!
thank you -very good video and excellent tips. makes a lot of sense regarding doing 1 at a time and testing.
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!
Thank you for sharing your experience!!!
Fantastic video! The shotgun approach advice was great!👍👍
Excellent tips.
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 :)
Excellent information on Caps👍
This is the way.
Excellent, excellent advice. Thanks. I'm in the process of repairing 2 Ferrograph 2As and a Vortexion WVB. Your vid is good. :)
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.
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. ;-)
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 :)
That was the kind of basic stuff I like to think I am way above. Until I realise I’m not. Thanks for the tips! You got a new subscriber
This is huge! Thanks!
Good job and great advice. I'm about to recap my Peavey Bandit 112 made in the States between 2000-2004. Kind regards from Mexico amigo!
Great advice. Thanks for the video.
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.
I learned something today, thank you.
The mis marked circuit boards can get very interesting when power is applied! We blew up two brand new sets of capacitors before we caught on!
Excellent tips. Thank you.
Thank you! Great advice!
Wonderful, valuable video.
sound advice - as usual. enjoy your videos a lot thx.
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.
They were interesting days, I worked for PHILIPS whilst studying for Electronics Engineering and Electro-Mechanical Engineering Degrees.
Then Joining the Military in 1970, serving for 20 years.
The manufacture of Electronic devices ceased, with production facilities closing, and operations being sent offshore.
I am familiar with all the brands you mention.
(Magnavox is a division of PHILIPS)
I was repairing Magnavox Radios and TV at age 8 ... Being taught by my uncle (Moms brother)
The same happened more recently with the Automotive manufacturing industry, and their component suppliers, Borg Warner for instance,
all ending their manufacturing operations.
In those early days, everything was Vacuum Tubes, then hybrid devices began appearing in the early 1970s.
I still have a VTVM a high-quality Analog Multimeter, and other equipment that is 50 years old and older.
Some of it is former Military equipment, I expect it will be dumped after I am dead.
I claim that if the US President was half as smart as the President of China, he would subsidize shipping costs to overseas
locations, as does China.
This makes buying Chinese products very cost-effective.
The US Government is taking its orders from the U.N. and it CREDITORS, the international Banking Cartel.
instead of making the purchase and shipping of US made products viable, the US wasted trillions on supporting
overseas Military bases where the locals do not want them.
The Grand scheme of the International bankers is to make CHINA great, and exploit the people over the following 500 years
as was done with America. as the population grew. - The US is now dead in the water and will sink whether the people like it or not.
All that can be done is to pacify and brainwash the people with a load of BS to prevent a revolution and civil unrest, until such
time that population control, tracking/surveillance is in full operation.
What we are seeing now are dress rehearsals and system testing in the guise of COVID-19 Plandemic
@@andrew_koala2974 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.
Thank you for this informative video. Currently have one older tape deck and one large cap in the back k of it has black gunk. I never saw black gunk like it before. Thinking it was a bad cap(cap itself looks fine), then I found your video and learning it was factory glue and not a leaky cap. Thanks again
Good advice well served!
All great tips. Thank you!