I did a very short (and not very good) video a couple of years ago showing the digital signals on the ADC on the 8842A, it may be of interest to you if troubleshooting the unit, as it gives you an idea what to expect or check for.
This was using the Logic Analyser inputs of my scope, my notes from the time on the video:
Scope patterns of digital on ADC and TP101, triggering from TP201, troubleshooting incorrect readings on display, vs input voltages or resistances.
Scope shows the digital outputs for the resistor ladder, and TP101 output which is fed back into the A/D converter IC.