<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">In the simple solutions to complex problems department: it was a bad IC socket. The spring for pin 15 of the oscillator had snapped off. The whole socket actually disintegrated as I was removing it.<div class=""><br class=""></div><div class="">Thanks again for all the assistance.</div><div class=""><br class=""></div><div class="">e</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 20, 2016, at 11:36 AM, mail <<a href="mailto:mail@m4moti.com" class="">mail@m4moti.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div bgcolor="#FFFFFF" text="#000000" class=""><p class=""><font face="Helvetica, Arial, sans-serif" class="">Try taking out U431 --
Osc B 3340. It might be that that is bad and its output is at
DC (+6V?) that is causing OscA to get stuck at a very high note
and thus fail to step through the tune/scale procedure. Or
check U433 -- that opamp might be bad. <br class="">
It might not be the switch but the input into the switch 1/4
U429. Read the VC at U428.15 for 0-5V. <br class="">
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<div class="moz-cite-prefix">On 6/19/16 22:29, Eric Frampton wrote:</div><blockquote cite="mid:1CF44034-E0CC-4F75-9836-01A3668577DE@ericframpton.com" type="cite" class=""><pre wrap="" class="">So now, it’s a very short list: the only thing that isn’t working is oscillator 1A. I’m guessing the Autotune routine is shutting it down because it can’t control it for some reason. I’ve got a solid signal on the related 4051 (U415) and op-amp (U421). Oddly, I’m seeing about +6V on pin 1 of U429 (the output of the 4016) which doesn’t appear on any other voice, so thinking I had a bad 4016 I swapped that. No change. Also tried swapping the 3372 for a known good one in case that 3372’s input was bad and Autotune couldn’t hear the oscillator. Again, no change.
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