Hi, I'm trying to debug the last remaining problem in my Polysix refurb, it's regarding the LFO signal. The KLM-367 has been replaced with a Kiwisix board successfully and my local tech also did the 369 and 371 mods as indicated in the Kiwisix manual, all verified with good continuity.
Symptoms:
- If I set either MG Delay or Speed down to 0 the MG enters a fast LFO state which doesn't respond to speed knob adjustments.
- If I set two or more of the parameters entering IC2 in KLM-369 (MG Speed, Delay, Level, PWM Speed) down to 0 it will provoke a program fault and light up all the LEDs in the front panel.
- To take it out of program fault I just need to move one or more knobs away from 0.
- To bring it out of the unusual fast modulation state I just need force Mod Wheel modulation (which is now carried through the IC2 MUX in KLM-369 too, as per Kiwisix modification).
As the fault seems to be affected by many different signals it looks to me like a badly muxed MG signal. IC2 MUX in 369 looks suspect but then I don't understand why it only happens when taking values down to 0 and works perfect when you don't. Muxed signal travels through the purple ribbon cable to Kiwisix which could also be at fault. I can't discard the Kiwisix is doing something wrong interpreting the muxed data but shipping the board back to AU if the fault is somewhere else is overkill. Most recent boot and firmware have also been re-applied to Kiwisix. I haven't seen any possible points of failure in KLM-366 as I don't think the problematic signal enters the voice board.
I'd love if someone could help me out with a diagnose before taking any further steps. I don't have a scope to analyze the muxed analog data though.
Thanks in advance.