[Amps] How Do You Know When Filter Caps Begin to Fail?

[Eddy Swynar]

On 2012-03-28, at 12:16 PM, Pete Smith N4ZR wrote:

> I have an SB-220 that dates at least to 1978.  There is no external sign 
> of any problems, and the amp has been heavily used in contests for at 
> least 20 years.  It still delivers over 1300 watts on 80-20.  Is there 
> going to be any warning of a capacitor failure?  Will there likely be 
> any cascading damage to other components? Is it conventional wisdom that 
> I should replace them as a precaution?
> 


Hi Pete,

When the filter caps in my filter string started to expire, one by one, the fuse in the 2.5 KV power supply would simply blow...

I finally grew tired of replacing them one by one, & simply wholesale replaced all of them. Surprisingly, the caps lasted some 32 years---but electrolytics seem to be like lightbulbs in that they all "age" at surprisingly the same rate. I guess once you lose one, "...it's time"!

~73~ de Eddy VE3CUI - VE3XZ