PDP 11/40 AC LO and M7235 (Status K5 Module)

LO > are 3.53v, which is lower than the expected +4.8v. This tells me there is Have you confirmed these are steady DC voltages Or could the signals be oscillating with that as the average value? There is a capacitor in the H742 that if it fails (and it does...) the ACLO and DCLO will oscillate at mains frequncy (or probably twice it). Certainly on the 11/45, this really confuses the CPU microcode. It's the obvious smoothing capacitor for the supply to the ACLO and DCLO circuit. -tony Yes, steady voltage, but I agree with your point. My question though is, will the M7235 "go lower" if it detects inbound AC LO is too low and lower it some more, or is the additional lowering of voltage a symptom of a fault in the M7235 as well as the h742a. hope that makes sense...I ask because it's exactly 1/2 the voltage when installed. DC LO on the other hand is not changed with or without M7235 installed. AC LO = 1.76v - with M7235 installed (3.52 / 2 = 1/76) AC LO = 3.52v - with M7235 disconnected b