Overall, the scope won't calibrate, but the two healthy channels will look calibrated after the procedure fails. The two bad channels will not work properly on the 1Meg input impedance after the failed calibration.
The failed 50ohm inputs are 99.9% due to bad input hybrids, it doesn't take much of DC to blow the input (even the 50ohm resistor is integrated). It appears there is a chinese guy on EBay, selling these hybrids (expect a chunk of PCB with the chip soldered? on it). I did not buy any and don't know anybody that did, so the risk is all yours if you decide to go for.?
Or you may want to hunt for another 54831 as a part mule, this is what I did and now have spares for the rest of my life.
