eskojramo wrote:
> Hello everyone.
>
> I´m newbie here and cs80 and cs60 owner from Finland. Second cs80
> should come from London next week. I wonder if i find here someone who
> can solve my problems with cs80. The problem is that in ch-2 voice #4
> doesn´t sound at all? In ch-1 it´s normal but ch-2 it´s like muted.
> Also voice #6 sounds very loud, like only aftertouch could hear very
> loud but normal sound is quiet? I have repaired all the downstears ic-
> chips and add ceramic-capasitors under KAS-board for every chips like
> oldcrow adviced. So total of over 50 new chips! That´s why i think the
> main problem is somewhere else. I have think that maybe M-board-5 and
> 6? Please help me if someone understand my problem cause can´t find
> any help from here Finland! Thank you for your excellend sites.
> ESKO
>
Hi Esko.
Welcome to the group! I wish we could have some kind of gathering and
all meet and fix up our gear, like the AH meetings (or classic car
groups), but everyone is so spread out, and it would be insane (and cost
a fortune) to have everyone bring their CS-80s to one place. We'd
probably look so suspicious we'd be raided by Homeland Security :^)
I assume you have test equipment, including a multi-meter and an
oscilloscope. I'm a little confused. How did you already replace all
the CMOS chips if you aren't getting the keyboard until next week? Did
you go to London to work on it? Also, another thing about the
"Downstairs" boards and replacing CMOS. There are more CMOS
chips/missing bypass caps on the two KBC boards in the upper rack. I'm
pretty sure Crow's (great) guide didn't include those boards, which is
why I was short some parts and had to order more.
Anyway, back to your keyboard. It could certainly be the M boards. It
should be pretty easy to trace with a 'scope. The card that makes no
sound could be a bad trigger. I think the easiest way to troubleshoot
would be to pull the bad card from the frame, along with the same
M-board from the other channel. Make sure you don't short the boards to
anything! Set the panel to be the same for both channels and just start
tracing the good board vs. the bad one. There's lots of trimmers that
could be affecting volume. Just go through the adjustment procedures,
or isolate first by comparing the boards (compare envelope outputs,
outputs of the various VCAs, etc). Nothing magic, just signal tracing.
Good luck & let us know how it's going.
David
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