I am currently repairing/adjusting a HP 6114A that i bought on ebay. This device has been built after 1980, so the schematics from the original documentation (1972) may be somewhat outdated.
Mainly i only had to clean the device (the cables are managed in small PVC tubes... these tubes are terrible, after 30 years they are sticky from the softeners leaking out of the material. I had the same in my HP 6827A). See picture... it looks like oil but these are the softeners.
The 10-turn current potentiometer had to be changed, no big issue (only one minor aspect - the actual Bourns device from this line has less sealing than the original one in the device).
Every other aspekt in the device seems to work perfectly - but when testing the crowbar circuit i saw something i currently do not understand: After fireing the crowbar the Output Voltage changed to approx. -0.5V. How can this happen? The crowbar thyristor in the original schematics should just make a short between the output connectors, there is no negative power source at the thyristor.
Any hint before i have to reverse-engineer the schematics (without disassembling the device...)?