Thanks! I will check that area very carefully.

John.


"spudnuty" wrote in message
oups.com...

John F Miller wrote:
Thanks for your quick reply.

I suspect a capacitance issue based on the problem not occurring (or even
reversing) when I touch a ground on the board (e.g., the audio input
ground). When tapping, there's no specific component that is most
sensitive
and, if, instead of tapping, I apply a more constant force to the
components, I cannot reproduce the problem. I have disconnected and
reconnected all the connectors to the main board with no effect. I have
looked at the underside of the board with a magnifying lamp but couldn't
detect any obvious problems.

John.

wrote in message
oups.com...
How does tapping on the board narrow it down to a capacitance issue?

Any mechanical vibration testing that changes the symptom points to a
connection problem. It is possible, though highly unlikely, that the
leads to a capacitor have become partially disconnected internally.

I would start by a good visual going over with a light and magnifying
glass the solder connections on the bottom of the board.

Sonys from this period had a solder problem esp around the tuner and
tuner board. I repaired a few recently with this problem. Sam talks
about it he
http://www.eio.com/repairfaq/REPAIR/F_sonytune.html
Very careful inspection is a must. Some of the solder might have to be
sucked off and replaced. The bad joints have a frosted look with a
grainy look and sometimes veins running through them. I usually reheat
everything and resolder everything that looks bad. Quite tedious. Just
did an eMac with the same problem.
richard