ISE 10 1606W 1600 RPM behaving badly

I have a 7 year old ISE machine which runs through its program for a while (maybe 10 minutes), then the display goes blank. If the machine is turned off/on, it will resume on a completely different timing for the program, even though the dial looks like the same program: eg the Cotton Eco cycle is 42 minutes. When it dies (blank display, all operation stops), an off/on will turn it to (say) 1:18, so the timing that doesn’t resemble the original program timing. I can sometimes limp it through the cycle by forwarding it to ‘rinse’, ‘drain’, ‘spin’. The machine spins, drains, fills just fine if it gets to that part of the program.
I have done the usual fault finding (even though there are no error codes): checked the pump, drum moves freely and without noise, belt looks brand new and brushes do not appear worn. It has not had heavy use: 3-5 times a month.
Although the fault finding says that modules very seldom go wrong, I fear that the problem is the ultra expensive module which costs pretty much the same as a new washing machine – and on a machine where every other part is in good nick. However does anyone else have any ideas? Any help would be much appreciated! Thanks, Marie