Discussion about the Korg PolySix synthesizer

Actually, IC39-3 is a virtual ground node due to op amp IC19, so it should be sitting 
at 0V all the time.   My mistake.   But how about pin 7 of IC 19?   This is also calledTP2.    If pin 3 of IC31 is sitting at -10V, then the outputs would probably be at that 
voltage, as you have said before, so maybe that chip is OK.   IC9-1 should have something 
like 5-8 different voltage levels if you hold 5 notes.   According to the schematic, it's about 
0.5V / octave, so you should be able to see this voltage changing as you play 
different notes.   The total time is divided into ~8 different time slots, and the voltagesfor the 5 notes are each assigned to one of these time slots.   If you play low C, then the 
next C up, then the next C, etc, until you have 5 oscillators on (use hold mode for this)than at IC9 you should see 5 levels, each 0.5 volts apart.   If you play the notes in 
ascending order, I think you may see a stair step pattern at IC9-1 with the voltage increasing0.5V each step, then jumping back down at the end.  There will be a couple of other levelsin there as well, but you should be able to see 5 levels repeated which correspond to your notes.If you don't see that at IC9-1, then maybe check each output of IC7 and 8 for good digital levels.
IC9-1 should be -10.7/10 times whatever you have at IC9-7 with ~5V added to it.   

      From: "mpe1969@tpg.com.au [PolySix]" <PolySix@yahoogroups.com>
 To: PolySix@yahoogroups.com 
 Sent: Monday, May 4, 2015 7:12 AM
 Subject: Re: [PolySix] Re: Key assign mode issue
   
    Thanks, I had another look tonight. I tried to upload some oscilloscope photos but they didn't seem to save to my album. IC9 has a dc around -2 to 2.5v that rises to about -0.5 then drops to around -4v then returns to around -2.5v. (as a pattern) I took some photos..... Hitting keys does not seem to influence this patternIc39 (the one above ic31) does not have anything happening on pin3. IC31 has -10v on pin3.I was about to replace ic31 but thought I would hold off as ic9 doesn't seem to be doing what you described.Will try again with the photos!Thanks again  #yiv8421380418 #yiv8421380418 -- #yiv8421380418ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv8421380418 #yiv8421380418ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv8421380418 #yiv8421380418ygrp-mkp #yiv8421380418hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv8421380418 #yiv8421380418ygrp-mkp #yiv8421380418ads {margin-bottom:10px;}#yiv8421380418 #yiv8421380418ygrp-mkp .yiv8421380418ad {padding:0 0;}#yiv8421380418 #yiv8421380418ygrp-mkp .yiv8421380418ad p {margin:0;}#yiv8421380418 #yiv8421380418ygrp-mkp .yiv8421380418ad a {color:#0000ff;text-decoration:none;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ygrp-lc {font-family:Arial;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ygrp-lc #yiv8421380418hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ygrp-lc .yiv8421380418ad {margin-bottom:10px;padding:0 0;}#yiv8421380418 #yiv8421380418actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv8421380418 #yiv8421380418activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv8421380418 #yiv8421380418activity span {font-weight:700;}#yiv8421380418 #yiv8421380418activity span:first-child {text-transform:uppercase;}#yiv8421380418 #yiv8421380418activity span a {color:#5085b6;text-decoration:none;}#yiv8421380418 #yiv8421380418activity span span {color:#ff7900;}#yiv8421380418 #yiv8421380418activity span .yiv8421380418underline {text-decoration:underline;}#yiv8421380418 .yiv8421380418attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv8421380418 .yiv8421380418attach div a {text-decoration:none;}#yiv8421380418 .yiv8421380418attach img {border:none;padding-right:5px;}#yiv8421380418 .yiv8421380418attach label {display:block;margin-bottom:5px;}#yiv8421380418 .yiv8421380418attach label a {text-decoration:none;}#yiv8421380418 blockquote {margin:0 0 0 4px;}#yiv8421380418 .yiv8421380418bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv8421380418 .yiv8421380418bold a {text-decoration:none;}#yiv8421380418 dd.yiv8421380418last p a {font-family:Verdana;font-weight:700;}#yiv8421380418 dd.yiv8421380418last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv8421380418 dd.yiv8421380418last p span.yiv8421380418yshortcuts {margin-right:0;}#yiv8421380418 div.yiv8421380418attach-table div div a {text-decoration:none;}#yiv8421380418 div.yiv8421380418attach-table {width:400px;}#yiv8421380418 div.yiv8421380418file-title a, #yiv8421380418 div.yiv8421380418file-title a:active, #yiv8421380418 div.yiv8421380418file-title a:hover, #yiv8421380418 div.yiv8421380418file-title a:visited {text-decoration:none;}#yiv8421380418 div.yiv8421380418photo-title a, #yiv8421380418 div.yiv8421380418photo-title a:active, #yiv8421380418 div.yiv8421380418photo-title a:hover, #yiv8421380418 div.yiv8421380418photo-title a:visited {text-decoration:none;}#yiv8421380418 div#yiv8421380418ygrp-mlmsg #yiv8421380418ygrp-msg p a span.yiv8421380418yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv8421380418 .yiv8421380418green {color:#628c2a;}#yiv8421380418 .yiv8421380418MsoNormal {margin:0 0 0 0;}#yiv8421380418 o {font-size:0;}#yiv8421380418 #yiv8421380418photos div {float:left;width:72px;}#yiv8421380418 #yiv8421380418photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv8421380418 #yiv8421380418photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv8421380418 #yiv8421380418reco-category {font-size:77%;}#yiv8421380418 #yiv8421380418reco-desc {font-size:77%;}#yiv8421380418 .yiv8421380418replbq {margin:4px;}#yiv8421380418 #yiv8421380418ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv8421380418 #yiv8421380418ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv8421380418 #yiv8421380418ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv8421380418 #yiv8421380418ygrp-mlmsg select, #yiv8421380418 input, #yiv8421380418 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv8421380418 #yiv8421380418ygrp-mlmsg pre, #yiv8421380418 code {font:115% monospace;}#yiv8421380418 #yiv8421380418ygrp-mlmsg * {line-height:1.22em;}#yiv8421380418 #yiv8421380418ygrp-mlmsg #yiv8421380418logo {padding-bottom:10px;}#yiv8421380418 #yiv8421380418ygrp-msg p a {font-family:Verdana;}#yiv8421380418 #yiv8421380418ygrp-msg p#yiv8421380418attach-count span {color:#1E66AE;font-weight:700;}#yiv8421380418 #yiv8421380418ygrp-reco #yiv8421380418reco-head {color:#ff7900;font-weight:700;}#yiv8421380418 #yiv8421380418ygrp-reco {margin-bottom:20px;padding:0px;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ov li a {font-size:130%;text-decoration:none;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv8421380418 #yiv8421380418ygrp-sponsor #yiv8421380418ov ul {margin:0;padding:0 0 0 8px;}#yiv8421380418 #yiv8421380418ygrp-text {font-family:Georgia;}#yiv8421380418 #yiv8421380418ygrp-text p {margin:0 0 1em 0;}#yiv8421380418 #yiv8421380418ygrp-text tt {font-size:120%;}#yiv8421380418 #yiv8421380418ygrp-vital ul li:last-child {border-right:none !important;}#yiv8421380418