So you can use a 20 thanks but the Zener is ok .But I'm getting 60v where it should be 0v . I have 60v at the following points. On E,B,C of H714, H715 . At all points of R748 (tested ok) at H712, H713 . The Base of H702 is high at 10v . Nothing seems to be over heating although I don't leave it on for long. I attached the schematic, P-700 L-CH is where the trouble is. Would something open cause this ? Thanks