Hello all. I need help with this old preamp. It has a tube MC section, heavily regulated, using two 6DJ8 tubes, one for each channel. MC section is a separate entity, before the MM section, so two separate inputs. MC section started to motorboat. Signal goes thru, and the volume is fine. I checked the plate voltage and it's only 30v, coming from the PS, and after the regulators I get only about 10V on 6DJ8 plates. Knowing Jadis and their idiosyncratic designs I expected something strange but not this. I checked all electrolytes around, and they all check fine, with ESRs in .26 ohm range, and uF within 5%. There is a pot on each plate, to regulate the voltage, I assume. Perhaps they have to be tweaked. Since there is no service manual available, I'm shooting in the dark. Any help is appreciated. Thank you.