Jump to content


Please note: You can easily log in to MPN using your Facebook account!

Poly Six Circuit Board Prognosis? Warning Big Picture


Michael Wright

Recommended Posts



  • Replies 9
  • Created
  • Last Reply
First thing I would do is check continuity on every pin of the 74LS08 (IC31) chip using a multi-meter. That area looks to have the most corrosive damage. Chances are you'll have to remove that IC and solder in hard wires where the traces are open. The damaged nearby larger traces look to be much easier to repair. I'm not seeing anything here that can't be fixed by someone with half decent soldering skills.
Link to comment
Share on other sites

There's plenty of info available on this exact issue with the Poly 6. One thing I failed to mention is you need to clean/neutralize the board of acid residue. Baking soda and/or maybe lemmon juice seems to be the recommended cleaner of choice. You will have to remove any chips where acid got underneath in order to adequately clean it. Also check for shorts between pins/ traces, not just opens.

 

Good luck!

Link to comment
Share on other sites

Would you guys help advise me as to how bad you think this is please?

Bad enough. While I agree with Markyboard that the majority of the damage is near IC31, it certainly appears to encompass an area beyond that. Traces near IC23 and IC25 seem to be damaged, D15 and R91 show corrosion, and resistor pack R17 might have been affected - leaking electrolyte often gets into components via their leads. IC30 bears inspection as well.

 

Good soldering skills would be needed, as well as experience in doing this type of repair. If I were working on this, the first thing I'd do is brush off any loose corrosion. The NiCd battery's electrolyte is alkaline, so washing the board with a weak acid (vinegar is often used) to neutralize it is a good idea, then rinse off with distilled water. Otherwise, my esperience is that after a repair any residue left from the battery can reactivate when the humidity is high, causing further problems.

 

See http://www.oldcrows.net/~oldcrow/synth/korg/polysix/index.html

Yamaha: Motif XF6 and XS6, A3000V2, A4000, YS200 | Korg: T3EX, 05R/W | Fender Chroma Polaris | Roland U-220 | Etc.

 

 

Link to comment
Share on other sites

Even if you could clean it, the corrosion has done too much damage. It looks bad.

Cleaning is just the first step. A skilled servicer can fix this, just not easily.

 

Yamaha: Motif XF6 and XS6, A3000V2, A4000, YS200 | Korg: T3EX, 05R/W | Fender Chroma Polaris | Roland U-220 | Etc.

 

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...