Hi, I'm repairing an old 54506b 4-channel oscilloscope, and there seems to be a problem with channel 4.
So far I've replaced the lithium cell, did an inspection of the mainboard and started the self cal. CH4 vertical calibration fails (gain 00001h, trigger 00030h), and I have no idea where to look or how to interpret these codes. I swapped attenuators but the problem persists. Could someone point me in the right direction?