Discussion about the Korg PolySix synthesizer

Hi group

My P6 is seriously noisy - a very noticeable hiss. Your classic noisy op amp type symptom. 

Is the P6 known for fried op amps / op amps on way out? 

(I've tried the foil insulator trick, but that hasn't helped the noise - indeed turning effects OFF makes no difference, so not the effects board)

The hiss/hum is worse when the attenuator is on lowest or highest settings. 

-4 is just about usable.

Is it likely something on the KLM-370 board that's on its way out? 

Could IC14051 be to blame? 

Should I consider a recap? If so, total recap or just certain boards?

Any help / advice appreciated

Cheers