Korg Mono/Poly

Some news:
After several attempts of reviving the power supply I bought a 15v, -15v and 5v power supply and installed it today.

Good news is that it works and almost every aspect of the monopoly is working.
The only problem I have now is that if the KLM398 board is connected, the sound of the osc is a weak distorded high pitched sound and I can not pitch the sound (either with the keyboard or arp or transpose).

If I disconnect the board, I have 4 perfectly sounding osc which I can change waveform, but still no pitch control.

I thought the 398 was the culprit but I changed the 2x TL072 and it did not change anything.

I guess the problem is with voltage control of the OSC. Where should I investigate ?
i checked the voltage on the connectors of every board and I read the 15v, 15v and 5v.