[Amps] Results from new PSUD... resistor b4 the B+ filter caps !

[Gary Schafer]

> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
> On Behalf Of Ron Youvan
> Sent: Thursday, February 11, 2010 4:50 PM
> To: amps
> Subject: Re: [Amps] Results from new PSUD... resistor b4 the B+ filter
> caps !
> 
>  >> Has anyone actually experienced a shorted filter C? Open C is far
> more
>  >> common, in my experience.
> 
>  >> In more than 50 years of electronics I have never seen a shorted
>  >> aluminum electrolytic cap. I have replaced hundreds if not thousands
>  >> of open ones and I have seen shorted tantalums on many occasions,
> but
>  >> that's all. I am sure it must happen but it seems to be exceedingly
>  >> rare.
> 
> 
> > How many would you like me to send from well known commercial amps?
> 
> > I always save various failed components as a teaching aid to those not
> > familiar with amplifier service.
> 
>    With 50 years of fixing (and building) electronic thingies and
> 47 years as a broadcast engineer, I do not recall finding a shorted
> electrolytic capacitor unless it was damaged by an outside influence
> like a short elsewhere.  Tantalums every so often, if exposed to
> ripple they will fail.
> --
>     Ron  KA4INM - I'm proud to be Chuck's pop!

You guys must live a different life than Carl and me.
I think that I have seen more shorted caps than open ones. Most old radios
have shorted filter caps or will short soon after powering them up.
Most amplifiers that I have seen that had old caps in them will short and
pop the breaker. One sure way to kill them is to have a rectifier leg short
out. The ac will short the caps.

73
Gary K4FMX