Voltech PM3000A rebooting itself after a while

[kahuna0k]

Hi,

I was able to get a Voltech PM3000A "not working for parts" VERY cheap. When I powered it up, it boots up, it seems to be working! I try some measurements and yep, it works pretty well.
 
But after a couple of minutes or so it rebooted itself. It kept working for another while and then reboots again. That cycle continues for ever, it seems that when I'm actually using it (pressing buttons and changing settings) it takes longer to reboot (although it could be some kind of bias, I need to actually time it .

First, I thought that it could be something getting hot and failing, but the fact that after reboot, it takes a while to reboot again makes me think that there is something broken in the logic. A visual inspection doesn't show anything clearly broken, I suppose I'll have to dismantle it and try to see what happens when it reboots with an scope, but I do not know even where to start. Any clue?