[sdiy] burned, soda-soaked SH-101 (with pics)

Ken Stone sasami at hotkey.net.au
Tue Jun 7 11:00:16 CEST 2005 

Chances are the burn is a wear-and-tear burn associated with an under-rated
component being used. It may still be functional. It is either a diode, or a
zener diode performing some sort of regulating function. It may be higher up
the circuit chain of part of the circuit that has failed/shorted out,
causing too much current flow through it.

Ken

>Excellent. Thanks for the response. Do I need to remove the ICs or
anything? I imagine the socketed components should go, but what about those
soldered to the PCB? 
>
>Also, what do you make of the burn? It is labeled D8 on the schematics here:
>
>http://www.physicsenterprises.andrews.edu/diy_archive/manuals/roland/sh101/
sh101_7.gif
>
>http://www.physicsenterprises.andrews.edu/diy_archive/manuals/roland/sh101/
sh101_6.gif
>
>(lower left, both)
>
>Again, many thanks,
>
>
>Chad
>  ----- Original Message ----- 
>  From: Tim Curtis 
>  To: Chad Coffman 
>  Sent: Tuesday, June 07, 2005 1:01 AM
>  Subject: Re: [sdiy] burned, soda-soaked SH-101 (with pics)
>
>
>  If it's soda, then the best way to clean the PCBs is to totally remove
them from the synth and run them under water.  Distilled water is best, but
generally tap water works just fine.  You can just run them under the
faucet, or use the shower in the case of larger PCBs.  You may want to
follow this with a rinse of distilled water.
>
>  After this, follow up with compressed air to dry it if possible.  You
particularly don't want the water to stay in the pots and switches. 
>
>  Alcohol won't work too well with water based spills like soda or beer.
>
>  Tim
>
>
>  Chad Coffman wrote: 
>    I just received an SH-101 purchased over eBay, which was advertised as
"not working". The problem, according to the seller, is that it simply does
not power up. This was confirmed upon unpacking and plugging the unit in. 
>
>    So I take the unit apart. Look over everything. The first ominous sign
is that the PCBs are soaked in soda (well, perhaps not soda, but something
that was once a liquid but is now a sticky, brownish semi-solid). The second
ominous sign is a burn near one of the most soda-soaked areas. Pics here:
>
>    Front (80k) :
>
>    http://home.comcast.net/~chadcoffman/sh101burn1.JPG
>
>    Back (70k) :
>
>    http://home.comcast.net/~chadcoffman/sh101burn2.jpg
>
>    There are a few other curious-looking anomolies which could be causing
problems, but these two issues appear to be most worthy of my immediate
attention. 
>
>    Two questions:
>
>    1: What is the easiest way to clean these PCBs? I tried isopropyl
rubbing alcohol and q-tips, but this was proving to be a tireless endeavor.
It would take about 20 hours at the rate I was going. 
>
>    2: What is that burnt part and where do I find a replacement?
>
>    As always, many thanks in advance,
>
>
>    Chad
>----------------------------------------------------------------------------
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>Checked by AVG Anti-Virus.
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>  
>
>------------------------------------------------------------------------------
>
>
>  No virus found in this outgoing message.
>  Checked by AVG Anti-Virus.
>  Version: 7.0.323 / Virus Database: 267.6.4 - Release Date: 06/06/05
><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
><HTML><HEAD><TITLE></TITLE>
><META http-equiv=Content-Type content=text/html;charset=ISO-8859-1>
><META content="MSHTML 6.00.2900.2627" name=GENERATOR></HEAD>
><BODY text=#000000 bgColor=#ffffff>
><DIV>
><DIV><FONT face=Arial size=2>Excellent. Thanks for the response. Do I need to 
>remove the ICs or anything? I imagine the socketed components should go, but 
>what about those soldered to the PCB? </FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2>Also, what do you make of the burn? </FONT><FONT 
>face=Arial size=2>It is labeled D8 on the schematics here:</FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2><A 
>href="http://www.physicsenterprises.andrews.edu/diy_archive/manuals/roland/
sh101/sh101_7.gif">http://www.physicsenterprises.andrews.edu/diy_archive/man
uals/roland/sh101/sh101_7.gif</A></FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2><A 
>href="http://www.physicsenterprises.andrews.edu/diy_archive/manuals/roland/
sh101/sh101_6.gif">http://www.physicsenterprises.andrews.edu/diy_archive/man
uals/roland/sh101/sh101_6.gif</A></FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2>(lower left, both)</FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2>Again, many thanks,</FONT></DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2></FONT> </DIV>
><DIV><FONT face=Arial size=2>Chad</FONT></DIV></DIV>
><BLOCKQUOTE 
>style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px;
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
>  <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
>  <DIV 
>  style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color:
black"><B>From:</B> 
>  <A title=sexsymbol at execpc.com href="mailto:sexsymbol at execpc.com">Tim 
>  Curtis</A> </DIV>
>  <DIV style="FONT: 10pt arial"><B>To:</B> <A title=chadcoffman at comcast.net 
>  href="mailto:chadcoffman at comcast.net">Chad Coffman</A> </DIV>
>  <DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, June 07, 2005 1:01 
>AM</DIV>
>  <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [sdiy] burned, soda-soaked 
>  SH-101 (with pics)</DIV>
>  <DIV><BR></DIV>If it's soda, then the best way to clean the PCBs is to
totally 
>  remove them from the synth and run them under water.  Distilled
water is 
>  best, but generally tap water works just fine.  You can just run them 
>  under the faucet, or use the shower in the case of larger PCBs.  You
may 
>  want to follow this with a rinse of distilled water.<BR><BR>After this,
follow 
>  up with compressed air to dry it if possible.  You particularly don't 
>  want the water to stay in the pots and switches. <BR><BR>Alcohol won't work 
>  too well with water based spills like soda or
beer.<BR><BR>Tim<BR><BR><BR>Chad 
>  Coffman wrote: 
>  <BLOCKQUOTE cite=mid010d01c56b2d$2bfcdf20$42071318 at pimpki19w9gg4k 
>    type="cite"><META content="MSHTML 6.00.2900.2627" name=GENERATOR>
>    <STYLE></STYLE>
>
>    <DIV><FONT face=Arial size=2>I just received an SH-101 purchased over
eBay, 
>    which was advertised as "not working". The problem, according to the
seller, 
>    is that it simply does not power up. This was confirmed upon unpacking and 
>    plugging the unit in. </FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>So I take the unit apart. Look over
everything. 
>    The first ominous sign is that the PCBs are soaked in soda (well, perhaps 
>    not soda, but something that was once a liquid but is now a sticky, 
>    brownish semi-solid). The second ominous sign is a burn near one of the
most 
>    soda-soaked areas. Pics here:</FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>Front (80k) :</FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2><A 
>
href="http://home.comcast.net/%7Echadcoffman/sh101burn1.JPG">http://home.com
cast.net/~chadcoffman/sh101burn1.JPG</A></FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>Back (70k) :</FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2><A 
>
href="http://home.comcast.net/%7Echadcoffman/sh101burn2.jpg">http://home.com
cast.net/~chadcoffman/sh101burn2.jpg</A></FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>There are a few other curious-looking
anomolies 
>    which could be causing problems, but these two issues appear to be
most 
>    worthy of my immediate attention. </FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>T</FONT><FONT face=Arial 
>    size=2>wo questions:</FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>1: What is the easiest way to clean these
PCBs? 
>    I tried isopropyl rubbing alcohol and q-tips, but this was proving to be a 
>    tireless endeavor. It would take about 20 hours at the rate I
was 
>    going. </FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>2: What is that burnt part and where do I
find 
>    a replacement?</FONT></DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>As always, many thanks in
advance,</FONT></DIV>
>    <DIV> </DIV>
>    <DIV> </DIV>
>    <DIV><FONT face=Arial size=2>Chad</FONT></DIV><PRE wrap=""><HR
width="90%" SIZE=4>
>No virus found in this incoming message.
>Checked by AVG Anti-Virus.
>Version: 7.0.323 / Virus Database: 267.6.4 - Release Date: 06/06/05
>  </PRE></BLOCKQUOTE>
>  <P>
>  <HR>
>
>  <P></P>No virus found in this outgoing message.<BR>Checked by AVG 
>  Anti-Virus.<BR>Version: 7.0.323 / Virus Database: 267.6.4 - Release Date: 
>  06/06/05<BR></BLOCKQUOTE></BODY></HTML>
>
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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