Yamaha CS80

Hi Tim

Any news on the 150?


Cheers



Bob
On 18/07/2014 08:25, Tim Conniff tconno@... [yamahacs80] wrote:
> dummy load may become pivotal in determining the source of the issue.
> Alternatively, of course, you could substitute another source of power 
> if available, and i don't mean another cs50 supply, I mean ANY other 
> capable source.
> Given the whine's prevalence on the power lines, you might also want 
> to disconnect the juice to the voice cards all at once and see if it's 
> still being heard, just to further rule out stuff.
> Btw, I have found a 150, just haven't had time to check it yet.
> good luck
> Tim
>
>
> On Thursday, July 17, 2014 11:38 PM, "Bob Stewart 
> bob@... [yamahacs80]" <yamahacs80@yahoogroups.com> wrote:
>
>
> I don't have a dummy load unfortunatley, but did short the sense 
> lines and look at it.
> Seemed to be OK, but might need to run it for a while to let it warm 
> up first.
>
> Might just be that something's beginning to fail under load. Just 
> really annoying that it's showing up on all the power lines. Might 
> have a chance to look at it further today, but have a MonoPoly to 
> tune, and a Prophet 5 to diagnose over at a clients.
>
>
>
> On Friday, July 18, 2014, Tim Conniff tconno@... 
> <mailto:tconno@...> [yamahacs80] <yamahacs80@yahoogroups.com 
> <mailto:yamahacs80@yahoogroups.com>> wrote:
>
>     Can you remove the supply, give it all needed dummy loads, and or
>     short sense lines to their respective power lines? Then you can
>     determine if it is strictly from the supply, or a function of the
>     load inducing a resonant freq, or other anomaly. I assume you have
>     a scope.
>     Tim
>
>
>     On Thursday, July 17, 2014 11:04 PM, "Bob Stewart
>     bob@... [yamahacs80]" <yamahacs80@yahoogroups.com>
>     wrote:
>
>
>     Only two fuses on the CS50.
>     Voltages are all there, but there's this signal sitting on top of
>     them.
>     Synth works fine other than the whine, and a duff LFO chip.
>
>     Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
>
>     B
>
>     On Friday, July 18, 2014, laurie laurie@...
>     [yamahacs80] <yamahacs80@yahoogroups.com> wrote:
>
>         are all 3 fuses intact?
>
>
>         ---- On Thu, 17 Jul 2014 11:14:08 -0500
>         *bob@...
>         [yamahacs80]<yamahacs80@yahoogroups.com>* wrote ----
>
>             Hi
>
>
>             Just servicing a CS50, and it's constantly outputting a
>             whine of about 4120Hz.
>
>             Unit came to me a bit battered as the PSU had shaken loose
>             and trashed a few things inside.
>             PSU PCB had become cracked, so replaced that with a
>             working one purchased from Synthparts.
>             Recapped the new PCB before I fitted it.
>
>             I've done the usual, changed the logic on the KAS board
>             and the S/H board, replaced power decoupling caps
>             throughout etc.
>
>             The only difference is that originally it took a minute or
>             so to manifest... now it manifests immediately.
>
>             I can see the signal on all power lines.
>
>
>             Any thoughts?
>
>
>             B
>
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