Discussion about the Korg PolySix synthesizer

Andy,


> Just wanted to clarify something. Looking at the transistor, sloped face
> towards you, is the reverse of what you see in the schematic. So the
> left-hand base physically is the right hand one on the diagram. I have some
> further readings for you as the emitter voltages don¹t look quite right. 

Correct.

 
> Pin 1: fixed 5.0v

Good

> Pin 2: -13.95v to ­3.5v (0 ­10 on MG freq)

Well it goes down to -13.95v but only is hitting 0.35 to 0.4v on the top end.

> Pin 3: 5.4v to 5.6v  (0 ­10 on MG freq). This centre pin is the emitter and
> this should also alter in voltage as you adjust VR5

Yes when you rotate MG Freq but no change when adjusting VR5.

> Pin 4: Fixed 5.0v

Good.

> Pin 5: 4.7 to 4.9 as above.

Good.


> 
> BTW Have you noticed the transistor is symmetrical? You can solder it in
> either way!
> So, as you can see. Pin 16, IC21 should fluctuate quite a bit depending on
> the MG freq. setting. Sorry I am not getting to the bottom of this for you.

When adjusting the MG Freq Pin16 of IC 21 is only shifting perhaps a half of a volt on this board.

> This remote diagnostic business is pretty difficult at the best of times.


I really appreciate the support in getting this one running.

- Daniel