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 Post subject: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 1:36 am 
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Hey All,

Have a dilemma.

This is a stereo 14 watt 6BQ5 amp.

A section of a six year old electrolytic cap in my main Packard Bell stereo has opened up. I heard a pop then hum. This a CE 40+40+20+20. I bridged in a 40mfd momentarily and the hum quieted instantly.

Needless to say I am quite irritated.

My question is, remove that one section from service and patch a single in, or replace the entire cap? The ONLY reason I'm asking this because the cap is only six years old. I also suspect this section might have been unstable from the very beginning. It would occasionally hum but would clear up.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 2:07 am 
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Hello Artcurus,
can you post the model of the radio also the voltage rating of the caps you used far the electrolytic caps go .

Sincerely rich


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 2:29 am 
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Packard Bell RPC 30 The tuner is model number 7TU12

The amp is a DPA 30-3.

The original caps were rated at 450v if I recall correctly. The replacement cap was rated at 525.

Replacement cap was this one

https://www.tubesandmore.com/products/c ... 40402020-f


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 4:34 am 
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Location: Riverside Ca. 92504
I am working on a Zenith radio and had recapped it two months ago with new E caps. I worked on it today and it did not play. After replacing a couple of out of tolerance resisters I went back and checked the caps I had put in. One was bad. It was a 20 MMD 50 volt. I replaced it with one rated at 160 volts and the radio is now playing but needs an alignment. I would replace them all because if one fails another one could follow shortly. It also depends on how much work it is to fix the problem. If it is easy just go for the quick fix knowing one may fail in the future. Tom


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 4:53 am 
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tomb123 wrote:
I am working on a Zenith radio and had recapped it two months ago with new E caps. I worked on it today and it did not play. After replacing a couple of out of tolerance resisters I went back and checked the caps I had put in. One was bad. It was a 20 MMD 50 volt. I replaced it with one rated at 160 volts and the radio is now playing but needs an alignment. I would replace them all because if one fails another one could follow shortly. It also depends on how much work it is to fix the problem. If it is easy just go for the quick fix knowing one may fail in the future. Tom


Thanks Tom,

Yeah the more I think about it, it might be better to dump the whole cap. It's not worth it just have to go back and bypass another section. The cap is easily replaced. It's just irritating and that cap wasn't exactly cheap.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 5:15 am 
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Perhaps the nicer grade Nichicon's made in Japan from Mouser would be best bridged in underneath can
if there's room on chassis? (may have to bridge them with resistors for high voltage handling)...
I've used them in lots of amp repairs and no problem's yet.

Thanks for sharing about the CE cans and this issue, I have one CE can I bought new 4, 5 yrs ago
and never put in my H.H. Scott 222C amp (all other electrolytics replaced), perhaps I should go the Nichicon route
and restuff, if the old original can in there now ever fails


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 12:34 pm 
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What voltage is actually running on the cap?


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 4:05 pm 
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Here ya go...

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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Sun 01, 2019 6:25 pm 
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As I recall, 6 years was a bit more life than I got from the multi-section electrolytics in my Eico HF-20. This was around 50 years ago, with US parts and US replacements. Close proximity to a hot 5U4 may have been a factor in the short lifetimes.
-Chuck


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 12:55 pm 
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I can't understand why anyone in the modern era would still use a multi-section cap. Nostalgia perhaps? Multi-section caps made sense in the 1950s and 1960s because individual 450v electrolytics were large and expensive. Also, chassis space was limited. Neither of these constraints apply in 2019. When restoring, I always just clip off the cans and use individual caps inside the chassis. There is plenty of room once you replace all of the old wax and paper film caps with modern equivalents. Modern multi-section cans cost a fortune when compared to individual caps. If one section fails, you have to replace the entire can. Worst of all, sometimes the sections bleed voltage into other sections. The money you save on new "cans" can be better spent on higher-quality individual capacitors. Seems like a no-brainer.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 2:15 pm 
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HI, a 450 volt cap should be large enough, the peak voltage is around 413 Volts Dc if your rectifiers are good. but that doesn't leave much headroom for line voltage surges.
it just sounds that the original cap was bad from the start, I would replace with single 500 plus DC caps just to be safe.
Rich


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 3:04 pm 
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For decades, it was common accepted practice to replace one failed section of a multi-section cap with a discrete replacement cap.
Not sure why it would be any different today?
Maybe more importantly is to review any other causal issues that could have resulted in a premature failure.

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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 5:20 pm 
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I never recommend replacing a single section of a multi-section cap. The reason is if one section has dried out and failed it is indicative the electrolyte is breaking down and the other sections won't be far behind.

As far as re-stuffing caps, I offer two choices when I do a job for a customer. They can either have it restored operational or cosmetic. If it is operational I would remove the old can and put in single caps on terminal strips or wherever needed to make the appropriate connections. If they want to spring for the additional costs of a cosmetic restore then I would re-stuff and maintain the appearance as original. It's their choice.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 5:32 pm 
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Thanks for follow up post all. As it turned the entire cap was compromised, most of the sections had drifted downward, one over 50%. I did replace it with another can but if this one fails, I'm going the separate route.

I'm chalking this one up to one off bad can.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Dec Mon 23, 2019 5:43 pm 
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Artcurus wrote:
Thanks for follow up post all. As it turned the entire cap was compromised, most of the sections had drifted downward, one over 50%. I did replace it with another can but if this one fails, I'm going the separate route.

I'm chalking this one up to one off bad can.


I think you took the correct approach in testing the remaining sections to see if and why they were compromised.

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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Jan Wed 08, 2020 7:02 am 
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I've seen very early unexplainable failures with CE can caps. I had one that shorted after less than a year and took our a power transformer.

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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Jan Wed 08, 2020 3:44 pm 
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I've heard more than a few stories of CE Manufacturing capacitors failing in a short period of time. I'd steer clear of them. I've always found their 55 degree C temperature rating most peculiar.


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Jan Wed 08, 2020 5:45 pm 
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928GTS wrote:
I've heard more than a few stories of CE Manufacturing capacitors failing in a short period of time. I'd steer clear of them. I've always found their 55 degree C temperature rating most peculiar.

Me too...

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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Jan Thu 09, 2020 12:31 am 
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55 c degree temp does sound peculiar, especially in our vintage electronic field!
After reading these latest posts (thanks guys!), I think I'll just run some nice Nichicon's off in a corner somewhere of the chassis,
rather than replace the can with a CE I already bought 4, 5 yrs ago, in my HH Scott 222C when it's original can ever kicks the bucket.
-Kent


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 Post subject: Re: Capacitor question- Six year old E cap death
PostPosted: Jan Thu 09, 2020 4:03 pm 
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I would trust a 50 year old name brand cap more than a modern no-name cap. I've seen way too many problems with off brand caps in modern equipment to trust them in vintage equipment.

I'm surprised they are really making multi section caps. I can't imagine the quality control in such a low volume operation is very good. They would have a much more reliable and cheaper product if they just installed modern caps in their cans.


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