Megger pat32 portable appliance tester

[downwind27]

I've had a Megger PAT32 for quite a few years but now it's playing up. Takes ages to start up and often sticks on the display test routine. I noticed that after pressing the two outer switches it shows 'cal' in the display and stays there - presumably waiting for some input. A calibration function is not mentioned in the user manual and I can't find any service information anywhere - does anyone have any clues? There are a couple of pots inside the unit so there must be some setting up procedure somewhere.

[shakalnokturn]

No experience with this model, a few things you could check:

Traces of battery leakage or corrosion.
Poor or dirty contacts: test sockets, internal fuse holder, relays, power switch...
Bad capacitors: look more specifically around any SMPS section HV or high current source, CPU supply.

If it is still working once you are past the long startup time, going by the spec sheet, there are a number of tests you could carry out with a DMM, clamp meter, resistors to check if the PAT32 is generating voltages and currents in the correct ranges. This could point you to what section may be failing.