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

[Rude 66]

D8 looks like and probably is a diode.  doesn't it say on the schematic what kind it is? if you're lucky, it's just something like an 1n4148, which costs a few cents. 
the question is: what made it burn? 

first the cr, now this: you don't seem to have much luck with ebay purcheases.. or do you buy them cheap and broken to fix them up yourself?


r./



  ----- Original Message ----- 
  From: Chad Coffman 
  To: diy synth 
  Sent: Tuesday, June 07, 2005 10:23 AM
  Subject: Re: [sdiy] burned, soda-soaked SH-101 (with pics)


  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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