Discussion about the Korg PolySix synthesizer

FWIW, I've made pin-for-pin replacement of the RAM using regular low 
power RAM SMD chip and PCB adapter with pins. Only slightly wider than 
real chip. Still have a few if anyone's interested. I used to sell them 
to a tech repairing P6 by the dozens, and since dawn of KiwiSix there's 
no use for them anymore.

You can check RAM's leaking current in the circuit, inside P6 by 
measuring voltage across the diode that goes between battery and RAM 
with decoupling capacitors (C36+C40) and 4011 (IC25). It should be 
nearly zero. If it's more than 0.1V, leakage is too high. But you gotta 
be quick, because voltmeter input resistance will charge the capacitors 
pretty fast, unless you have an option to switch it to 1Gohm.
There is no such diode in service manual, but it has to be added when 
replacing NiCad for Li battery. That's the diode you put instead of 100 
ohm R91 resistor that was originally there.

Roman

W dniu 2016-02-06 o 21:32, jw_dewdney@yahoo.com [PolySix] pisze:
>
>
> Thanks Bob - no that's QUITE a convincing argument/explanation... I'll
> get the APLs instead... anyone had any experience with cooking their
> SRAM chips?? or are there any good tests to find out? I guess checking
> patch storage etc would be the obvious - but not sure if there are
> better/more critical tests?
>
> I was hoping chip quik would work for extracting these but it's useless
> without a decent extraction tool - which I'm trying to get my hands
> on... (open to suggestions on this too!)
>
>