Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries
OK lets start from the beginning what made you change the two pcbs in the first place?
I winder if I sent my first reply correctly. I changed the pcbs having liked in forums on possible faults. These suggested it might be the pcbs
I understand that you have mentioned the pcbs earlier but I would be grateful if you would humour me and tell me what was your initial problem ~ was it only that the back was freezing up and that you had a slight negative temperature. Was it actually freezing up the milk or other liquids?
Whilst I see that you have read earlier posts, there are a number of things that can cause this problem and many are not directly attributable to the power board or electronic thermostat. These two pcbs work together to control the units electronic and electrical systems but have no control over the mechanical side of the operation ~ Ian