Waeco CF50 fridge shutting down on 240 volts

Hello, I have a Waeco CF-50 fridge that works beautifully on 12 volts but has started cutting out after a while if connected to AC (mains) supply. It is the newish type with digital temperature readout. It's a few years old. It previously worked perfectly on AC.

The pattern seems to be that it starts and runs fine, cools the fridge down a few degrees, then stops altogether. The shutdown is complete and includes the digital display going blank. No error light.

Sometimes it restarts after a while, runs for a bit (much shorter duration this time), then shuts down again. I can also restart it by unplugging the AC cord and plugging back in, but the same thing happens - runs for a while, then shuts down. When it does restart, the compressor seems to run at a lower RPM initially before stepping up to full speed, then soon afterwards it stops and everything goes blank. Maybe that's normal behaviour - not sure.

I tried a new power lead but had the same result. Fuse (next to AC socket) looks good. Can't see any visible problems with the PCB that sits at the back of the power sockets, or with any of the connections.

I'm wondering if there's an overheating issue on the AC side of the control unit that sits at the side of the compressor with all the wires running out and connections marked by letters (the compressor says something about thermal protection or overheating protection on its side). I don't know whether the compressor has separate AC and DC windings, or the control unit includes a transformer/regulator to convert the AC to DC.

Or maybe it's a problem with some sort of voltage regulator/rectifier problem that sits between the AC mains supply and the DC control circuitry, and only comes into use when connected to AC power.

I've seen a lot of Waeco problems on forums but nothing specifically about a failure in only the AC side of the unit. I know there's a lot to be said about the relative merits of this fridge compared to others, strength and weaknesses etc, but really I'm just interested in advice on what might be wrong and how I might fix it.

Any help appreciated -thanks.