Discussion about the Korg PolySix synthesizer

check the reset line and do the reset adjustment per the service manual


On 2017-04-25, 06:16 rnw6ueo2ru3grihf5iabauttna56367yo4n5umk4@yahoo.com 
[PolySix] wrote:
> [Attachment(s) <#TopText> from
> rnw6ueo2ru3grihf5iabauttna56367yo4n5umk4@yahoo.com [PolySix] included
> below]
>
> Hi Everyone,
>
> I am currently rebuilding my Polysix and have replaced the battery
> damaged KLM-367 with one of Jed's new KLM-367A boards. Everything worked
> great for a while but recently the front LEDs have locked on Programs 1
> and 8. None of the Bank LEDs are lit, nor is the Manual button, and they
> do not respond when pressed. I tried resetting the circuit per the
> service manual, but to no avail as the LEDs will not return to Bank A
> and Program 1.
>
> Per this thread I also tried replacing C23 with a 10pF ceramic
> capacitor. While this did bring the amplitude of XTAL 1 and XTAL 2
> closer together, and I was able to confirm a 6MHz input at each point,
> it did not solve the issue. I then probed TP4 (Clock) and noticed there
> was a weak signal that did not resemble a clock waveform. Could this
> mean my RAM chip is defective? Has anyone else experienced this issue
> before? I have attached photos of the scope readings for reference.
>
> Thank You,
> Daniel
>
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