[sdiy] P5 VCO Output Level Low

Tony Kalomiris weplar at gmail.com
Fri Mar 3 11:27:11 CET 2017


Hi list, just a general query as I await arrival of said keyboard.

Is this a documented, engineering change order. Never heard of this before.
The problem is one of the voice VCO's (3340) has a consistently low output,
in fact half the amplitude, or 5v pk-pk. The tech said he checked the
common analog, swapped 3340's, checked psu, all check-out. I suggested
something is loading it down further down the line. He desoldered the
analog switches (waveform select, 4016's I gather), and practically socket
every relevant i.c. in there - this guy's gone desoldering mad ever since I
sold him my Denon Sc-7000!

I am not asking to be spoon fed, but just for old times sake - I got out of
this biz two years ago - I wouldn't mind a crack at his. Troubleshooting is
my forte after all. I was just wondering if there was some revisions (oh
this one is a 3.x?). or known problems , 4016' etc.

Will post in here when I get it on the bench and check the obvious stuff,
pcb traces, load Rx, etc.
Oh he's tried old and new 3340's, he says.

a bientot,

Tony K
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