Korg Poly800/EX800 Users group photo

Yahoo Groups archive

Korg Poly800/EX800 Users

Index last updated: 2026-04-28 23:27 UTC

Thread

Dead? Poly 800 mkii

Dead? Poly 800 mkii

2016-10-19 by lifeisaforeigncountry@...

Hello fellow Poly800 users!

I have been talking to Mike via email about my poly 800 mkii issue, but I figured I'd post to the group as well to see if there is any input on the matter.

I picked up an "as is" poly800 mkII on ebay a few weeks ago. The synth wouldn't turn on at all. I opened it up and noticed many parts damaged by poor soldering/repair work in the power supply, namely Q1, which had several damaged traces. I repaired the traces, pulled another 774B from a partially working poly800 I had in my garage as well as a couple diodes and replaced those. The poly800 would power on, but the display reads "9.9.9." in the first 3, 7 segment displays to the left. It makes no sound and generates no midi data. I have tested the power supply and the +5 v calibrates fine, but the -5 volt sits at about -4.7v on boot, and then slowly decays over a couple minutes down to -4.6 and so on. Q1 gets extremely hot as well. I noticed pulling the eeprom on the digital delay board does not change the state of the synth, could it be a bad eeprom?


thanks! any help is appreciated!!


n8

Re: [korgpolyex] Dead? Poly 800 mkii

2016-10-20 by Michael Hawkins

I doubt very much that it's the EPROM. They rarely get corrupted. EPROM's are very stable devices. Much more stable than flash.
Get the schematics from the file section and by checking some of the basics.
/mike
Show quoted textHide quoted text
      From: "lifeisaforeigncountry@... [korgpolyex]" <korgpolyex@yahoogroups.com>
 To: korgpolyex@yahoogroups.com 
 Sent: Wednesday, October 19, 2016 12:25 PM
 Subject: [korgpolyex] Dead? Poly 800 mkii
   
    Hello fellow Poly800 users!  I have been talking to Mike via email about my poly 800 mkii issue, but I figured I'd post to the group as well to see if there is any input on the matter.  I picked up an "as is" poly800 mkII on ebay a few weeks ago.  The synth wouldn't turn on at all.  I opened it up and noticed many parts damaged by poor soldering/repair work in the power supply, namely Q1, which had several damaged traces.  I repaired the traces, pulled another 774B from a partially working poly800 I had in my garage as well as a couple diodes and replaced those.  The poly800 would power on, but the display reads "9.9.9." in the first 3, 7 segment displays to the left.  It makes no sound and generates no midi data.  I have tested the power supply and the +5 v calibrates fine, but the -5 volt sits at about -4.7v on boot, and then slowly decays over a couple minutes down to -4.6 and so on.  Q1 gets extremely hot as well.  I noticed pulling the eeprom on the digital delay board does not change the state of the synth, could it be a bad eeprom?
thanks!  any help is appreciated!!
n8   #yiv1052340462 #yiv1052340462 -- #yiv1052340462ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv1052340462 #yiv1052340462ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv1052340462 #yiv1052340462ygrp-mkp #yiv1052340462hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv1052340462 #yiv1052340462ygrp-mkp #yiv1052340462ads {margin-bottom:10px;}#yiv1052340462 #yiv1052340462ygrp-mkp .yiv1052340462ad {padding:0 0;}#yiv1052340462 #yiv1052340462ygrp-mkp .yiv1052340462ad p {margin:0;}#yiv1052340462 #yiv1052340462ygrp-mkp .yiv1052340462ad a {color:#0000ff;text-decoration:none;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ygrp-lc {font-family:Arial;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ygrp-lc #yiv1052340462hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ygrp-lc .yiv1052340462ad {margin-bottom:10px;padding:0 0;}#yiv1052340462 #yiv1052340462actions {font-family:Verdana;font-size:11px;padding:10px 0;}#yiv1052340462 #yiv1052340462activity {background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}#yiv1052340462 #yiv1052340462activity span {font-weight:700;}#yiv1052340462 #yiv1052340462activity span:first-child {text-transform:uppercase;}#yiv1052340462 #yiv1052340462activity span a {color:#5085b6;text-decoration:none;}#yiv1052340462 #yiv1052340462activity span span {color:#ff7900;}#yiv1052340462 #yiv1052340462activity span .yiv1052340462underline {text-decoration:underline;}#yiv1052340462 .yiv1052340462attach {clear:both;display:table;font-family:Arial;font-size:12px;padding:10px 0;width:400px;}#yiv1052340462 .yiv1052340462attach div a {text-decoration:none;}#yiv1052340462 .yiv1052340462attach img {border:none;padding-right:5px;}#yiv1052340462 .yiv1052340462attach label {display:block;margin-bottom:5px;}#yiv1052340462 .yiv1052340462attach label a {text-decoration:none;}#yiv1052340462 blockquote {margin:0 0 0 4px;}#yiv1052340462 .yiv1052340462bold {font-family:Arial;font-size:13px;font-weight:700;}#yiv1052340462 .yiv1052340462bold a {text-decoration:none;}#yiv1052340462 dd.yiv1052340462last p a {font-family:Verdana;font-weight:700;}#yiv1052340462 dd.yiv1052340462last p span {margin-right:10px;font-family:Verdana;font-weight:700;}#yiv1052340462 dd.yiv1052340462last p span.yiv1052340462yshortcuts {margin-right:0;}#yiv1052340462 div.yiv1052340462attach-table div div a {text-decoration:none;}#yiv1052340462 div.yiv1052340462attach-table {width:400px;}#yiv1052340462 div.yiv1052340462file-title a, #yiv1052340462 div.yiv1052340462file-title a:active, #yiv1052340462 div.yiv1052340462file-title a:hover, #yiv1052340462 div.yiv1052340462file-title a:visited {text-decoration:none;}#yiv1052340462 div.yiv1052340462photo-title a, #yiv1052340462 div.yiv1052340462photo-title a:active, #yiv1052340462 div.yiv1052340462photo-title a:hover, #yiv1052340462 div.yiv1052340462photo-title a:visited {text-decoration:none;}#yiv1052340462 div#yiv1052340462ygrp-mlmsg #yiv1052340462ygrp-msg p a span.yiv1052340462yshortcuts {font-family:Verdana;font-size:10px;font-weight:normal;}#yiv1052340462 .yiv1052340462green {color:#628c2a;}#yiv1052340462 .yiv1052340462MsoNormal {margin:0 0 0 0;}#yiv1052340462 o {font-size:0;}#yiv1052340462 #yiv1052340462photos div {float:left;width:72px;}#yiv1052340462 #yiv1052340462photos div div {border:1px solid #666666;height:62px;overflow:hidden;width:62px;}#yiv1052340462 #yiv1052340462photos div label {color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}#yiv1052340462 #yiv1052340462reco-category {font-size:77%;}#yiv1052340462 #yiv1052340462reco-desc {font-size:77%;}#yiv1052340462 .yiv1052340462replbq {margin:4px;}#yiv1052340462 #yiv1052340462ygrp-actbar div a:first-child {margin-right:2px;padding-right:5px;}#yiv1052340462 #yiv1052340462ygrp-mlmsg {font-size:13px;font-family:Arial, helvetica, clean, sans-serif;}#yiv1052340462 #yiv1052340462ygrp-mlmsg table {font-size:inherit;font:100%;}#yiv1052340462 #yiv1052340462ygrp-mlmsg select, #yiv1052340462 input, #yiv1052340462 textarea {font:99% Arial, Helvetica, clean, sans-serif;}#yiv1052340462 #yiv1052340462ygrp-mlmsg pre, #yiv1052340462 code {font:115% monospace;}#yiv1052340462 #yiv1052340462ygrp-mlmsg * {line-height:1.22em;}#yiv1052340462 #yiv1052340462ygrp-mlmsg #yiv1052340462logo {padding-bottom:10px;}#yiv1052340462 #yiv1052340462ygrp-msg p a {font-family:Verdana;}#yiv1052340462 #yiv1052340462ygrp-msg p#yiv1052340462attach-count span {color:#1E66AE;font-weight:700;}#yiv1052340462 #yiv1052340462ygrp-reco #yiv1052340462reco-head {color:#ff7900;font-weight:700;}#yiv1052340462 #yiv1052340462ygrp-reco {margin-bottom:20px;padding:0px;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ov li a {font-size:130%;text-decoration:none;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ov li {font-size:77%;list-style-type:square;padding:6px 0;}#yiv1052340462 #yiv1052340462ygrp-sponsor #yiv1052340462ov ul {margin:0;padding:0 0 0 8px;}#yiv1052340462 #yiv1052340462ygrp-text {font-family:Georgia;}#yiv1052340462 #yiv1052340462ygrp-text p {margin:0 0 1em 0;}#yiv1052340462 #yiv1052340462ygrp-text tt {font-size:120%;}#yiv1052340462 #yiv1052340462ygrp-vital ul li:last-child {border-right:none !important;}#yiv1052340462

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.