Discussion about the Korg PolySix synthesizer

--- In PolySix@yahoogroups.com, "hoggy_bogger" <yanbu@c...> wrote:
> I'm really hoping I can get some help / advice from you all.  Ok, 
> i'll state the facts once again:
> 
> My polysix fell out of tune last week, a few days before I was 
about 
> to play a show, and I decided to get in there and tune it.  I got 
it 
> rock solid in tune, and this is obviously where I went wrong - I 
had 
> it plugged in still -  and closed the cover down to put all the 
> screws in and saw a small flash from the center back portion of 
the 
> inside.  It seemed like it came from the center back board that's 
> screwed in with the metal plate, the one that holds the fuses.  
The 
> first of the two fuses blew out.  I looked around for quite some 
time 
> to see if I pinched any wires against the case or something 
obvious, 
> but couldn't find anything.  I bought new fuses and replaced, but 
> they blow out immediately when powered up.  
> 
> I'm pretty handy with a soldering iron and such, can plunder my 
way 
> through schematics - but not sure where to start and thought I 
better 
> ask some advice.  Thanks in advance for any help.  The most I can 
> offer this board is my patch dumps, I have a number that aren't in 
> your files area.



I would start by unpluging the power to each of the PCB's (use 
schematic to identify what plug is used for each board's power), 
then plug one at a time back in starting with the one you thing is 
least likely to be the problem. Switch power off plug in pcb, power 
on again, repeat for each PCB. When the fuse blows you know it's the 
last pcb you pluged back in. at pcb. Unplug it and plug the rest in 
a check the fuse does not blow (this will confirm that it is just 
this pcb). If it blows again you may have 2 pcb faults.

Once you located the problem PCB, I would look for something 
shorting out the power input, perhaps a component has been squashed, 
bent etc?

Sean