Discussion about the Korg PolySix synthesizer

If you have dismounted the keyboard in the sense that you left the
circuit board connected to the main board but removed the membrane, do
a continuity test to see if the two halves of the pad are engaged. I
had a keyboard once that had a microscopic connection that caused the
connection to be made. 

--- In PolySix@yahoogroups.com, "atuzzi" <antoniotuzzi@...> wrote:
>
> Hi polyfriends,
> 
> I decided to help my brother to resurrect his p6...
> 
> YEEEEEEkkkk: acid!
> 
> Ok you know was completely blocked, everywhere, everything...
> 
> action taken the OLDCROW procedure:
> 
> 1) removed battery
> 2) removed ic30 and 31
> 3) checked continuity
> 4) recreated dead traces
> 5) new lythium battery with diode in place and no more c40
> 6) new socketed 74ls08 ic30 and ic31
> 
> 
> status:
> 
> A) all digital control are ok (effect type, waveform, sub ecc ecc)
> B) all buttons of the programmer are ok
> C) I can see data changing on TP2  (I have no oscilloscope in place,
> but only a DM and a Logic probe (I'm not in my lab...))
> I can see minimal variation coming out from the comparator (lm393) but
> after that, the data is going in the 8748 (T0 pin 1) and is Missing in
> Action.
> I can see the inhibit working on the 2 4051, that should distribute
> the data on the buffers. But data at the output of the buffers is all
> blocked (all maximum value seems)
> 
> D) Key assigner problem:
> every time the p6 is turned on the note #56 (G in last octave) is on
> (GATE 0 is on). I need to switch the arpeggio on and off (or jump to
> unison and back to poly) to turn the note off.
> if an arpeggio is started, that #56 results always on.
> Is not a contact problem (I dismounted the keyboard). So seems another
> IC problem: Does anybody knows the correct logic test to do to
> individuate the faulting IC ?
> 
> E) As I have a couple of 8748 and a programmer is the .bin for the p6
> available somewhere ? (I'd like to have a backup for the 2 p6)
> 
> 
> thank you for your help
> 
> antonio
>