I'm very sorry to see that my minimoog voyager (performer edition) stopped working properly all of a sudden.. There is a very low volume of pops & crackles from the main out, and a higher volume of the same sounds from the headphones out. I can still hear that the oscillators & filters are working, but I can no longer hear them properly

I've tried updating the firmware & reloading the banks too. Funny part is, when I transmit the banks, that pops&crackles dissapear! But after the loading is over, they restart.
I've sent it to an authorised repair service in Istanbul, it took them almost 6 months just to tell me they couldn't repair my poor minimoog.
Any of these sympoms sound familiar to you? I'd appreciate all help you could advise...
Best,
Ali EREL