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?
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