[sdiy] strange PCB faults, was:OTA question

[Graham Atkins]

On 17 Sep 2010, at 17:01, Harry Bissell wrote:

> Were they caps that were defective of manufacture, were they  
> improperly installed
> (ie left to shake with ambient vibration) ?
>
> Were they misused (ie AC signals through a polarized electrolytic ???
>
> Its really not that common, although possible. That is not the first  
> thing I'd be looking for
> in a failed amp.

They were physically small and mounted against the PCB. They were  
polarised but
orientated WRT the DC offset on each stage. I recently rebuilt my Quad  
34 and removed
all (Some 16+) of them and they all had corrosion on the leads and PCB  
pads to some
extent (Manufactured Circa 1984). Not a well known manufacturer. I  
replaced them with
NP types.

Graham