Kastel KP50/26 ice machine

Having an ongoing problem with one of these ice makers. Every time I go to look at it, it behaves like it should. But leave it 2-3 days and it completely stops, and staff cannot restart it. Had it in the workshop, refixed the evap sensor which was loose, cleaned coil etc. ran fine for a few days, so took it back, couple of days later stopped again.
When I got to it today, I found red led blinking on board, which from memory is faulty fridge system. I switched it off and on again, watched it do 3 complete cycles until I got bored and went home. I don't think it is a fridge problem, suspect pcb, but do not know of anyone who deals with them.
Any of you guys know anything about these machines? It is getting very boring

Andy