Yamaha CS80

--- In yamahacs80@yahoogroups.com, David Rogoff <david@...> wrote:

> 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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4/10/2006

>Hi David and thanks for your reply.

I ment that the problem is for my first cs80, second cs80 should come
this week. I start to testing right away like you told. Thanks a lot.