Hello-
Having repaired many of these, I would suggest that the most likely
cause is damaged traces due to the battery leak.
Even if the board looks good, the traces around IC31 (which you
replaced) are VERY delicate, and carry data lines that, if damaged,
effect all of the functions of the synth.
If you have any experience with electronics, get hold of the schematic
and use a continuity tester to test all traces from that IC; if you
have a scope, that's even faster.
If not, you can send me the CPU board & I can look it over for you.
~GMM
analogsynthervice.com
choco wrote:
>
> 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.
>
>
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