Discussion about the Korg PolySix synthesizer

BTW,

It's generally not a good idea to solder anything in a device that is powered up.
Lots of soldering stations connect the soldering iron tip to earth ground, so if you
connect that to a point in the circuit, you are shorting it to ground. Also, it's just
safer to do any kind of mod, component removal, etc while power is off, so that if
you accidentally touch something near where you are working with the soldering iron, pliers, etc,
you don't risk shorting something out.

IMO, setting the reset trip point is not "jumping the gun". It shouldn't depend on whether
the rest of the circuit is running, except for the fact that the 5V supply exact voltage will
vary a bit with load (what the CPU is doing). But the change should be small. And setting
the trip point would confirm that the reset circuit is now working correctly and will keep reset
from glitching on later on when you are trying to troubleshoot something else. But I still suggest
that you measure the 5V supply as you connect and disconnect the 57K ohm (47 +10) resistor.
If it's not changing for some reason, then setting the trimpot won't work.

Something that I use all the time is a small piece of wire, maybe 8-12" long, with a little spring-loaded
clip/hook on each end. This would be perfect for connecting and disconnecting the resistor to those
posts. No soldering required, and you can do it with power on. There are two sizes of clips/hooks
that are easy to get. minigrabbers are the smaller size. I have maybe 4-5 wires with each size
on them. The larger size is good for connector pins or clipping onto typical DMM test leads.
The smaller size are better for clipping on the pins of an IC. I like to use these leads when monitoring
pins of a chip with a scope, as it's a little safer than using a scope probe. If you are using a probe and
it slips and short two pins of the chip together, you can damage a chip that may be tough to replace,
like the 8048, for instance, since it has P6 code in it.

These leads are very cheap on ebay.

Bob

--------------------------------------------

On Sat, 2/13/16, jw_dewdney@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

Subject: Re: [PolySix] Re: PROGRESS!!!!
To: PolySix@yahoogroups.com
Date: Saturday, February 13, 2016, 1:41 PM


okay Bob... thanks for the calibration info.
It's much more informative than the service manual, i
did it by soldering the resistor across the connector pins
inside the connector while the polysix was OFF. And then
unsoldering it while ON....  So it makes more sense to me
why it wouldnt work (unless a deeper problem is still at
play here as Roman suggested). Perhaps i shouldnt be trying
the calibration routine yet even?









#yiv8063138634 #yiv8063138634 --
#yiv8063138634ygrp-mkp {
border:1px solid #d8d8d8;font-family:Arial;margin:10px
0;padding:0 10px;}

#yiv8063138634 #yiv8063138634ygrp-mkp hr {
border:1px solid #d8d8d8;}

#yiv8063138634 #yiv8063138634ygrp-mkp #yiv8063138634hd {
color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px
0;}

#yiv8063138634 #yiv8063138634ygrp-mkp #yiv8063138634ads {
margin-bottom:10px;}

#yiv8063138634 #yiv8063138634ygrp-mkp .yiv8063138634ad {
padding:0 0;}

#yiv8063138634 #yiv8063138634ygrp-mkp .yiv8063138634ad p {
margin:0;}

#yiv8063138634 #yiv8063138634ygrp-mkp .yiv8063138634ad a {
color:#0000ff;text-decoration:none;}
#yiv8063138634 #yiv8063138634ygrp-sponsor
#yiv8063138634ygrp-lc {
font-family:Arial;}

#yiv8063138634 #yiv8063138634ygrp-sponsor
#yiv8063138634ygrp-lc #yiv8063138634hd {
margin:10px
0px;font-weight:700;font-size:78%;line-height:122%;}

#yiv8063138634 #yiv8063138634ygrp-sponsor
#yiv8063138634ygrp-lc .yiv8063138634ad {
margin-bottom:10px;padding:0 0;}

#yiv8063138634 #yiv8063138634actions {
font-family:Verdana;font-size:11px;padding:10px 0;}

#yiv8063138634 #yiv8063138634activity {
background-color:#e0ecee;float:left;font-family:Verdana;font-size:10px;padding:10px;}

#yiv8063138634 #yiv8063138634activity span {
font-weight:700;}

#yiv8063138634 #yiv8063138634activity span:first-child {
text-transform:uppercase;}

#yiv8063138634 #yiv8063138634activity span a {
color:#5085b6;text-decoration:none;}

#yiv8063138634 #yiv8063138634activity span span {
color:#ff7900;}

#yiv8063138634 #yiv8063138634activity span
.yiv8063138634underline {
text-decoration:underline;}

#yiv8063138634 .yiv8063138634attach {
clear:both;display:table;font-family:Arial;font-size:12px;padding:10px
0;width:400px;}

#yiv8063138634 .yiv8063138634attach div a {
text-decoration:none;}

#yiv8063138634 .yiv8063138634attach img {
border:none;padding-right:5px;}

#yiv8063138634 .yiv8063138634attach label {
display:block;margin-bottom:5px;}

#yiv8063138634 .yiv8063138634attach label a {
text-decoration:none;}

#yiv8063138634 blockquote {
margin:0 0 0 4px;}

#yiv8063138634 .yiv8063138634bold {
font-family:Arial;font-size:13px;font-weight:700;}

#yiv8063138634 .yiv8063138634bold a {
text-decoration:none;}

#yiv8063138634 dd.yiv8063138634last p a {
font-family:Verdana;font-weight:700;}

#yiv8063138634 dd.yiv8063138634last p span {
margin-right:10px;font-family:Verdana;font-weight:700;}

#yiv8063138634 dd.yiv8063138634last p
span.yiv8063138634yshortcuts {
margin-right:0;}

#yiv8063138634 div.yiv8063138634attach-table div div a {
text-decoration:none;}

#yiv8063138634 div.yiv8063138634attach-table {
width:400px;}

#yiv8063138634 div.yiv8063138634file-title a, #yiv8063138634
div.yiv8063138634file-title a:active, #yiv8063138634
div.yiv8063138634file-title a:hover, #yiv8063138634
div.yiv8063138634file-title a:visited {
text-decoration:none;}

#yiv8063138634 div.yiv8063138634photo-title a,
#yiv8063138634 div.yiv8063138634photo-title a:active,
#yiv8063138634 div.yiv8063138634photo-title a:hover,
#yiv8063138634 div.yiv8063138634photo-title a:visited {
text-decoration:none;}

#yiv8063138634 div#yiv8063138634ygrp-mlmsg
#yiv8063138634ygrp-msg p a span.yiv8063138634yshortcuts {
font-family:Verdana;font-size:10px;font-weight:normal;}

#yiv8063138634 .yiv8063138634green {
color:#628c2a;}

#yiv8063138634 .yiv8063138634MsoNormal {
margin:0 0 0 0;}

#yiv8063138634 o {
font-size:0;}

#yiv8063138634 #yiv8063138634photos div {
float:left;width:72px;}

#yiv8063138634 #yiv8063138634photos div div {
border:1px solid
#666666;height:62px;overflow:hidden;width:62px;}

#yiv8063138634 #yiv8063138634photos div label {
color:#666666;font-size:10px;overflow:hidden;text-align:center;white-space:nowrap;width:64px;}

#yiv8063138634 #yiv8063138634reco-category {
font-size:77%;}

#yiv8063138634 #yiv8063138634reco-desc {
font-size:77%;}

#yiv8063138634 .yiv8063138634replbq {
margin:4px;}

#yiv8063138634 #yiv8063138634ygrp-actbar div a:first-child {
margin-right:2px;padding-right:5px;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg {
font-size:13px;font-family:Arial, helvetica, clean,
sans-serif;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg table {
font-size:inherit;font:100%;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg select,
#yiv8063138634 input, #yiv8063138634 textarea {
font:99% Arial, Helvetica, clean, sans-serif;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg pre, #yiv8063138634
code {
font:115% monospace;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg * {
line-height:1.22em;}

#yiv8063138634 #yiv8063138634ygrp-mlmsg #yiv8063138634logo {
padding-bottom:10px;}


#yiv8063138634 #yiv8063138634ygrp-msg p a {
font-family:Verdana;}

#yiv8063138634 #yiv8063138634ygrp-msg
p#yiv8063138634attach-count span {
color:#1E66AE;font-weight:700;}

#yiv8063138634 #yiv8063138634ygrp-reco
#yiv8063138634reco-head {
color:#ff7900;font-weight:700;}

#yiv8063138634 #yiv8063138634ygrp-reco {
margin-bottom:20px;padding:0px;}

#yiv8063138634 #yiv8063138634ygrp-sponsor #yiv8063138634ov
li a {
font-size:130%;text-decoration:none;}

#yiv8063138634 #yiv8063138634ygrp-sponsor #yiv8063138634ov
li {
font-size:77%;list-style-type:square;padding:6px 0;}

#yiv8063138634 #yiv8063138634ygrp-sponsor #yiv8063138634ov
ul {
margin:0;padding:0 0 0 8px;}

#yiv8063138634 #yiv8063138634ygrp-text {
font-family:Georgia;}

#yiv8063138634 #yiv8063138634ygrp-text p {
margin:0 0 1em 0;}

#yiv8063138634 #yiv8063138634ygrp-text tt {
font-size:120%;}

#yiv8063138634 #yiv8063138634ygrp-vital ul li:last-child {
border-right:none !important;
}
#yiv8063138634

Hi Bob - yes I do try to be aware of such things - that's exactly why i didn't solder the pins with the power ON. But it was only after your contribution yesterday that I was able to understand the purpose of this routine and why you  have to do it with the polysix ON. I did DESOLDER live - but making sure i did what i thought was the 'downstream' (nearer to ground) pin first - so the resistor might absorb any potential - but figuring it was a very low voltage sensing circuit I didn't see harm in it - but in thinking about it - it's probably a dumb thing to do unless I understand the circuit 100%. I've learned my lesson in the past using a grounded soldering iron on live electronics -so it's something I usually avoid. The eevblog on youtube (by the way - for casual readers comming across this) has a great instructional video on such grounding issues with live circuits - called 'how not to blow up your oscilloscope -haha .. it's a good lecture!).

Yes I'm still looking for a good solution (via minigrabbers or mini alligators) for such purposes - i get a bit nervous with the DVM and OSC probes when hitting the chips - I seem to read stories about people blowing up components all the time. I think i've been very lucky - but yeah that's good advice and I will heed it and try to get something set up - maybe I'll get lucky finding something in the spare parts drawer....