Sequential Circuits Prophet 10 Rev 3 - Random Tune Mode Issue

Hello to everyone. Got a old Prophet 10 Rev 3 to service. No output. Recap power supply, replace tantalums from 2 voice boards, 2 complete keyboard bushing, calibration, etc. The synth work fine for 2 months, now everytime I power up, it goes to the normal tune procedure, them work for about couple of seconds then it goes again in tune mode, them work for another couple of seconds and goes again in tune mode…in loop.
Check voltages, ok, clocks ok, reset cpu ok.
Any clues to start the troubleshooting ?
Thank you

Without researching…

What conditions can cause it to tune? I thought it only did that if you pushed the tune button.

Is it reinitializing?

Thanks for the reply.
I don’t know the cause to enter in tune mode. I thought to that can only go in tune when you press the button, but in fact there’s no press and the led goes light.
In fact it seems that is always reinitializing… but in loop

Best regards,