samsung condenser dryer sdc14709

Hi , just wondered if any one has come across one of these samsung condenser dryers model sdc14709 with a odd fault , we have one that will come on for approx 3/4 minutes then completely shut down and no operation of the front control on/off will restore it to life .If we switch off at mains supply then switch back on then it restores it to working order for another 3/4 minutes then dies again .
We have checked the pcb for connection faults and all seems ok this but as its a back to back pcb board covered in resin then its seems unlikely to be dry joint on print side and difficult to pinpoint a specific fault .However giving the pcb a tap or twist does seem to have a positive effect for a short while . Having priced a new pcb (about £130) then it may be the only answer unless anyone has a scrap board for sale ( not found one on fleabay by the way) any suggestions most helpful thanks