[sdiy] Gibson G101

[Bob Weigel]

John, In my experience they used pretty good quality ones for the most 
part in these.  Do you have an esr meter?  Highly recommended... but I 
seem to recall on the Gibson I did a while back that some were bad in 
the LFO section.  I'll review my invoice...

Ok here's the deal on the 201 I worked on.   There was a leaky 
sub-filter cap for the reiterate circuit.  Minor value drifts on some 
sustain caps that I do think contributed to variations there.... but not 
a single cap was bad otherwise.  It was a bad transitor in the vibrato 
circuit.  And there was a bad neon bulb that wasn't firing in the opto 
coupling circuit.

-bob

John Henson wrote:

> I've just had delivery for repair one of these.
> It had just been shipped in from the States allegedly after a complete 
> overhaul, but it's casing is damaged, loads of screws are missing and 
> it doesn't work.
> Mind you, the cardboard shipping carton that it was in was perfectly ok.
> My question is, to what extent should I replace the electrolytic caps 
> in it, there are lots of them.
> My own instincts are that all PSU caps should be replaced as they get 
> the hardest time, followed by the main decoupling caps on each PCB, 
> but the grey area is the interstage, biasing and decoupling around the 
> small components. In my experience, they tend to be fine no matter 
> what age they are, and my only nemeses are Tantalums. You can get 
> faulty caps in any age of equipment, and they can be a b***ch to 
> isolate, but you know something is wrong.
> This is a rare and classic instrument, so I want to do no harm to 
> borrow the medical analogy, and ripping out 25 or so pcb's, all 
> hardwired together, would be risky.
> Any thoughts?
>
> John
>
>
>
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