Discussion about the Korg PolySix synthesizer

Hi!

After digging within the messages I haven't found any similar
situation, so I decided to post.

I bought a year ago and old polysix and it sounded fine to me (maybe
lower than expected, I use it with an old guitar tube amp and I have
to select the high output with master at 12 o'clock to get it at
almost the same level as the guitar is)

A mounth ago I noticed that I had lost all my patches (although it was
sounding great and every pot worked fine). I did know about the
battery issues, but it hadn't worried me until that moment. I opened
the polysix and noticed that the battery mounting clamps were broken
and the batery was not feeding the klm367A anymore.

Well, it had leaked a little bit, but the circuit was almost perfect
and there were no signs of corrosion elsewhere. I cleaned all the
board with alcohol and care, replaced the battery and the 74LS08N
which is next to it just for security and then I made a mistake.

I broke a trace and shorted accidentaly 5V and ground. 

After testing and noticing what the matter was, I removed that mistake
and everything seemed to work fine (the leds and so on), but when I
pluged the P6 to an amp (to the earphones too), I noticed that it
sounded weak and something like distorted. almost every pot didn't
affect as expected.

Do you have any idea of what can happen to my beloved P6?Any measure
that I could take from it to get deeper into? Unfortunately I don't
have an osciloscope to take accurate measures...

I also had a problem with 15Volt line, all the LEDs were ON when
starting up the P6, but never went OFF. In addition to it, the
Modulation LFO LED started blinking every time faster and faster until
it seemed to be just static ON. I solved it regulating the 15V pot to
get over 15.05 on my meter.

I will continue testing it, but it seems that I have reached my best
effort in front of it, and here in Spain it's almost impossible
finding a qualified vintage synth tech.

Thank you in advance.