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.