[volt-nuts] HP 3456A -3 Fault

[ed breya]

I agree these caps are the most failure-prone parts in the 3456A, and 
also the 3455A. Sometimes they also cause damage to other parts like 
the associated three-terminal regulators. Don't be surprised if 
there's still more to fix after cap replacement - but usually easy to find.

I had one where an LM339 status comparator was shot - I suspected 
over-voltage or reversal of an input polarity during the cap failure, 
even though it wasn't obvious how it could have done that. The 
diagnostics instructions in the manual worked very well and led 
quickly to the faulty part.

Ed