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 Post subject: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 5:25 pm 
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Joined: Nov Mon 12, 2012 8:56 am
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Location: Mississauga, ON
I watch a lot of videos on electronics repair. I am a follower of both shango066 (shango6) and radiotvphononut (radiotvnut) and something I've heard mentioned more than once by each of them is people having such an obsession with replacing capacitors in both vintage and post-1970s electronics as to send them hate mail via personal messages as well as put dislikes on their videos. I haven't really immersed myself into the hobby of electronics repair as of yet, but I myself do see a trend emerging concerning insistence of across-the-board replacements of electronic components even if technically unnecessary. One of my favorite examples is the intro to shango066's video showcasing the repair of a GE table radio.

https://www.youtube.com/watch?v=xDH0OpqQgI8

I honestly see a silver lining to this, as it really indicates to me that casual observers and more and more people in the general public are starting to care about the stuff, but it also strikes me as a weird and quite frankly hilarious thing to get upset about. Is it as much of a problem as it seems to me? Does anyone else have any stories to share about these kinds of people?


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 5:36 pm 
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Some people who aren't technically experienced don't understand that capacitors fail with age and need to be replaced. And nothing you can say to them will change their minds, until they experience a catastrophic failure caused by a part that could easily and relatively inexpensively been replaced.

Anyone who has actually serviced vintage electronics and tested those capacitors with the appropriate test equipment quickly learns that the vast majority of old paper and electrolytic capacitors are bad, to the point where it's a waste of time to even bother checking them. It's foolish to apply power to something that old until it has been properly serviced.

The problem occurs when rank amateurs think they know better than the pros who have done this for decades and learned the proper procedures decades ago.........

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 5:38 pm 
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Location: Maryland 20709, USA
Mikon8er wrote:
...insistence of across-the-board replacements of electronic components even if technically unnecessary.

The fallacy in your reasoning is your assumption that replacement is not "technically necessary".

Vintage capacitors are organic assemblies. They deteriorate over time.

I've been repairing radios for over 60 years. There was a time when I tested vintage capacitors because a significant percentage were still good.

That's no longer true. A very high percentage (over perhaps 80%) are now bad. Those that are currently OK will likely fail in service in a short period of time.

I have an excellent reputation for the quality of my repairs. I refuse to jeopardize that for the sake of saving a couple of bucks on parts. I replace ALL old electrolytic and wax/paper caps.

- Leigh

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 5:52 pm 
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Joined: Nov Mon 12, 2012 8:56 am
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Location: Mississauga, ON
What I'm really talking about is relatively new (1970s and newer) electronics with electrolytic capacitors that are not "worn" enough to justify replacement and still test good on ESR meters and capacitor checkers as well as people who chastise undertakers of repairs who don't necessarily replace all of the capacitors in the product in question. Sometimes, amateurs will try fix a product simply by diving right in to a full recap, only to discover that they haven't fixed the product or that they have, but unbeknownst to them, all they've done is perhaps fix some bad solder joints and/or replace one or a few bad caps. I am fully aware that hours of use and age in and of itself can warrant replacement, but this does not apply too all the repair jobs that go on out there.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 5:57 pm 
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Posts: 134
Location: New Castle, IN
When something is of sufficient age, I don't even test them anymore (specifically, paper in oil caps and electrolytics). I've tested several pulls for fun, and I've not had any that were still anywhere near good. I keep the old ones in case I ever get the restuffing bug, but for now, they're in a bag in the garage. Just because something will work, doesn't mean it works optimally or will continue to work. An ounce of prevention is worth a pound of cure, and all that jazz.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 6:11 pm 
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Mikon8er wrote:
What I'm really talking about is relatively new (1970s and newer) electronics with electrolytic capacitors that are not "worn" enough to justify replacement and still test good ......


Yes some will test good - and wholesale replacing of 45+ caps on a board can lead to bigger troubles. But 90% of the members here deal with vintage ('20s-'60s) equipment, and a wholesale replacement in vintage gear is warranted.

--- That said,

I've seen new caps fail upon initial turn-on in modern equipment, and more so in some military gear, with spectacular effects. Given that most no-name/oddball name modern electrolytic capacitors are made in China, some, if not most of the obsession is warranted. With oddball names, these sub-par caps are easy to find, and if I find more than 50% of a unit has sub-par (by name only....) capacitors, I'll shotgun the whole unit and replace every cap. Why risk a callback or a "hit" to your reputation? Caps are cheap, and rework costs time and money....

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 6:39 pm 
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Mikon8er wrote:
What I'm really talking about is relatively new (1970s and newer) electronics with electrolytic capacitors that are not "worn" enough to justify replacement and still test good on ESR meters and capacitor checkers as well as people who chastise undertakers of repairs who don't necessarily replace all of the capacitors in the product in question.
I never chastise anyone for doing or not doing something to the best of my knowledge. If I have I sincerely apologize.

Having said that, I watched a late 60's console stereo go up in smoke 9 years ago when the electrolytic capacitors gave up. That resulted in the console going directly into the dumpster.

Electrolytic capacitors really do have a limited life which can be greater or less depending on the conditions they have experienced over the last 30+ years.

The upside to electrolytic capacitor replacement is that it is dirt cheap insurance when the alternative can be the loss of an expensive and hard to find field coil speaker or power transformer. The labor to change an electrolytic is virtually nothing once you have it available enough to "test" properly. So I don't see any real advantage to not changing one at that time.

Electrolytic capacitors WILL fail at some point. The older they get the closer they are to their failure point regardless of how they test at this instant. That is just physics. When given the opportunity to extend that point for maybe another 30+ years for $5 and 30 minutes of labor that seems to be a pretty good deal.

For any paper dielectric capacitors the story is the same. Regardless of how they test, the insulating paper IS deteriorating and their end of life is approaching or already long overdue at 30+ years. The criticality of these failures is normally much less but there is at least one exception. This would be the "tone" capacitor that is often connected to the plate of the audio output tube. Failure of this capacitor can result in the loss of a hard to locate audio output transformer and/or Field Coil. So, once again, changing this part when the opportunity is available is real cheap insurance.

People can honestly do whatever they want as far as I am concerned. It's their radio. I just hate to see people save $5 and cost themselves $50, but to each his/her own.

Curtis Eickerman

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 7:14 pm 
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Joined: Oct Thu 02, 2014 5:57 am
Posts: 621
Location: Memphis, TN
I'm a definite FNG around here, so I just followed the advice of other more experienced members on here and began each of my projects with a complete recap. I just stuck all of the old caps in a bucket in case I ever wanted to do a re stuff.

Once I got some more gear, I tested a BUNCH of the caps I had saved just as a 'Huh, I wonder' kind of exercise. I think less than 3 in 10 'appear' ok, and I won't even go that far since I'm still working on the Heathkkt to test them at full working voltage. I can test for leakage at much lower voltages, and some of these old caps begin leaking around 10 volts. That'd be fun on a 6F6.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 7:19 pm 
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My stereo system uses an 80's vintage Yamaha C-65 preamp. When I got it there was a lot of hum in it. Interestingly, there is no ventilation in the cabinet! Taking off the cover, it was immediately apparent where the problem was, as the main PS caps were swollen. I had to replace them.

Now I am starting to hear a lot of grain in the phono section. The CD section still sounds great. This preamp is LOADED with electrolytics. I don't like to think about it, but I know at some point this 30+ year preamp will need a complete electrolytic re-cap. I am hoping to replace them with the new polymer electrolytics, which look to last a lot longer with 125 degree ratings.

I've also changed electrolytics in a number of 70's pieces.

The point is that yes, even 'newer' electronics still suffer from this electronic Achilles heal.

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 8:05 pm 
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Shango who...
Seriously... his youtube channel is for entertainment only.


:) Greg.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 8:22 pm 
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sets from the 70's are over 40 yrs old, approaching 50.

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 8:42 pm 
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Mikon8er wrote:
What I'm really talking about is relatively new (1970s and newer) electronics with electrolytic capacitors that are not "worn" enough to justify replacement and still test good on ESR meters and capacitor checkers as well as people who chastise undertakers of repairs who don't necessarily replace all of the capacitors in the product in question. Sometimes, amateurs will try fix a product simply by diving right in to a full recap, only to discover that they haven't fixed the product or that they have, but unbeknownst to them, all they've done is perhaps fix some bad solder joints and/or replace one or a few bad caps. I am fully aware that hours of use and age in and of itself can warrant replacement, but this does not apply too all the repair jobs that go on out there.

I hope you are not expecting a tidy answer to this. There are a variety of strategies out there, and everyone gets to pick the one that works the best for them.

This quote from Curtis captures my understanding of how things work:
Quote:
The upside to electrolytic capacitor replacement is that it is dirt cheap insurance when the alternative can be the loss of an expensive and hard to find field coil speaker or power transformer. The labor to change an electrolytic is virtually nothing once you have it available enough to "test" properly. So I don't see any real advantage to not changing one at that time.

Electrolytic capacitors WILL fail at some point. The older they get the closer they are to their failure point regardless of how they test at this instant. That is just physics. When given the opportunity to extend that point for maybe another 30+ years for $5 and 30 minutes of labor that seems to be a pretty good deal.


For me, the strategy depends on many factors---probably including what I had for breakfast the day I dive into a new patient.

80-90 years old: Just about all the capacitors and resistors go straight to the trash.
60 years old (1957)---at the dawn of the S/S era: Electrolytics still get "shotgunned", but some other parts are often OK. I just finished a Fisher 400 and was pleasantly surprised to find all the carbon comps good. and just about all caps ex. the electrolytics were either film or ceramic. (monster receiver, but one of the easiest re-furbs I've ever done. (Still need to do the alignment......ugh)

70s and newer: Now it's all S/S and everyone is making electronics---the technology is very advanced (just look at the electronics that went into space), but people are competing for price. You can have a relatively high-end stereo go belly-up in just a few years due to just one small electrolytic.
I recently overhauled THREE Pioneer receivers--all for the same customer. All the electrolytics were replaced. WHY?
1. the little ones are cheap. (See Curtis on the topic of cheap insurance.)
2. for a set like this (in my shop), it comes apart for cleaning, inspection, and access to parts. (and Pioneers are super easy to tear down and reassemble). Once it's apart, replacing all the electrolytics is no big deal.

I have no interest in charging a customer $300 for a complete refurbish and then have the set fail a few weeks later. Noone has ever asked me to "just get it working". If they did, I would politely tell them to go elsewhere.

And then there are the exceptions: My Tektronix scope (mil equivalent to the 7603) is still running on the original filter caps. For all I know, they are higher quality than what we sent up on Voyager 1 and 2. (Both still operating)


The bottom line: I will keep doing things my way, because I have a high success rate. Everyone else should continue doing it THEIR way--unless they learn a better approach. We can all coexist........

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 8:51 pm 
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Location: Port Dover, Ontario
I have just finished working on a 5 tube Rogers Majestic set model R166.

I replaced all of the capacitors in it.

Out of interest, I scraped off the the accumulated dirt and wax from the foil capacitors to check for date codes. All of them were made in 1946 or 1945.

I figured that it wasn't safe leaving >70 year old capacitors in the set! The new units probably cost me less than $5.

Joseph


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 8:54 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: North of Mpls, Minnesota
egg wrote:
Shango who...
Seriously... his youtube channel is for entertainment only. :) Greg.

After watching this video I now fully understand why this is called entertainment, it certainly doesn't have much to do with any accepted methods of radio repair. This guy wouldn't have lasted 20 minutes in a repair shop.

Video is here
https://www.youtube.com/watch?v=FY6Vqub68r8

Dave


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 9:03 pm 
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Its seems tremendously inefficient to work on something, even something made in the 1970s, without taking a few minutes and spending a few dollars to replace those capacitors.

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 9:07 pm 
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If it's my own stuff I may do minimal replacements. If it's for someone else all electrolytics and papers are going to get replaced, as well as some micas. As for someone getting all in a dither about what others do, I also find that more than a little amusing.

RRM


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 9:27 pm 
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easyrider8 wrote:
"Smoke is good." This is not exactly the quote I would want to hear from a guy working on a radio for me. :shock:

Agreed that smoking parts in an AA5 radio is usually not a catastrophe (no transformer and no field coil to end up being an expensive repair). However, that general statement is sort of a concern.

Then one of the first things he ends up having to do is (guess what) replace the electrolytic capacitors. :D

Curtis Eickerman

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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 10:13 pm 
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I'm kind of with RRM. If its say- something from the 70's or about that era I'll pretty much leave it alone. If something goes bang, oh well, its mine and I can in turn repair it. If on the other hand its something to be sold for the museum or its a customer then usually its wholesale replacement. 99.9% of what I work on are from the 30's-60's and so replacement of everything is a given.

After many 100's of sets, I've witnessed seeing a set that was recapped minus just one or two fail because that one remaining cap then shorts out. Just last week one of our members was working on an admiral TV. It was up and running well for hours with what he thought was fully recapped. And then he lost picture: A cap was under a cover the one of the IF cans and it decided to let go.

Old caps will generally have a high failure rate if the device they're in is used frequently.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 10:46 pm 
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I had a very expensive exotic brand CD player made in the late 90s that experienced damage due to electrolytic leakage. Shorted a power supply rail that came back to life after the offending cap was replaced. I shotgunned all the identical caps out of that one and found a couple more that were starting to leak at the bottom next to the board, thus concealing the problem. I don't recall that they were anything but brand name quality caps as it was a 2000+$ machine made in the US. Then again, I have had functional Japanese hi fi gear dating back to the 70s with nary a hiccup in the caps. Just noisy pots and flaky switches. I don't know if disuse or intense usage has any impact on the life of those solid state caps. My gut is that idling that gear once in awhile is more beneficial to the caps rather than decades of storage. Got a few old ham radios with original caps from the 70s. Caps might be deteriorating but has not shown up as a malfunction yet, and right now I don't have the time to change all the caps in every old thing I have here. Just when I restore an old radio, pretty much.


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 Post subject: Re: Public obsession with replacing capacitors
PostPosted: Feb Thu 01, 2018 10:59 pm 
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The 7603 is a very fine scope.

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