Have this Kenwood TS660, quad bander and the 10 watt wide band output stage keeps going into oscillation.When driven into a dummy load its perfect, but as soon as the load is slightly wrong it takes off.If the drive is taken to deck it also immediately takes off!.
Have replaced all electros(3) on output board and all 0.01 ceramic bypass caps(12).
Resoldered everything and double checked lead dress etc.
This problem has been with the unit for years but now is unusable unless the antenna is a perfect match.
Have also rechecked bias current 300mA for driver 2sc1971's, and 100mA for finals 2sc1972's.As per the service manual.(doen't make any difference if not set correctly!).
