Starting with the analog front end, one of the four channels.
These are easily accessible, remove 2 screws, then pull the module out.
Nice modular design, but quite complicated.
Two boards + Display board. Most recent datecode is 8940.
Ten relays, 11 trimcaps, 13 trimpots...
(the attenuator is not 1-2-5-10, but 0.1V, 0.12V, 0.15V,0.2V all the way to
100V, in total 31 settings)
Googled some of the components:
The 2 DIL40 are simple LED drivers
A1-5195 and A1-2540 in the ceramic DIL14 are high speed op-amps.
The UAA170 must be responsible for the LED bar display, similar to a LM3915.
I expected the A/D and RAM to be here, but no, nothing, must be somewhere else.