Sounds like a tricky one this. There is no point in replaceing the
151's is it is going to just burn them out, so I would sugest that
you reduce the area of the problem. Check the power rail caps and
look for any high voltage comming into the voice card in the EG area
as well as the filter. Use a working voice as referance.
Let me know how you get on :)
--- In
yamahacs80@yahoogroups.com, Stephen Teller <s.teller@...>
wrote:
>
> This list seems to be the only place to get the goods.............
>
>
> When no signal from a voice card is first traced to a VCA, where
the
> signal doesn't show, what methods do you use to troubleshoot
where
> and how it's being pulled down and overheating several chips in
the
> surrounding path. Obviously its a current draw issue, but I don't
> want to damage more components in the process of replace and
retest.
> (When replacing just the first VCA chip that has no output, it
> overheats the replacement if you leave it in circuit) IC3 and 4
are
> specifically troublesome, as they are common output.
>
>
> Thanks!
>
> Stephen Teller
>
> [Non-text portions of this message have been removed]
>