Nice - Happy to hear you're having a good break - Always wanted to visit the Canary Islands (and the Azores & Galapagos if we're listing islands I want to visit) - We will get there someday. I looked at the schematic for the 432 and there are a number of RC paths back to GND which I think is what is making the potentiometer read strangely - I'm going to put the unit back together and swap the cards to work out which one is problematic and then start diagnostics on that - Thanks for your suggestions., appreciate them.

Thanks - They're good units, especially for calibrating the ref outs on the 43X etc power meters. They seem to be plentiful right now so it might be a buyers market. I have the next part that was supposed to post today but Premiere Pro crashed and ate my project so I have to start again :(

Now I'm afraid to look... The replacement I bought was a Bourns unit but this one actually seems fine - I hope the issue is on Board A2 but I need to swap it into a working meter to see - I would prefer it to be on the board and not in the wiring harness or switches of the chassis.

@@tgsoapbox The Bourns ones often have better specs anyway.