Fridge dead completely on 12 volt

Hi all

Yes I have a Waeco so will take the flack as necessary BUT I plugged it into 12 volt before Easter and it won't go at all. No lights NOTHING. 240 runs as usual.

I have checked everything starting at the plug. I seem to have power all the way to the little circuit board where the 12 volt and 240 volt meet. It is a digital CF-35 with the voltage transformation inside the fridge. There are no obvious burn marks on the board though the little box in the middle wrapped in yellow cardboard looks like it has seen better days. It has a part number stamped on it with 4amp/25volts. Any chance this is the polyfuse? I figure the problem has to be here somewhere as the wires that leave it are the same whether on 240 or 12 volts.

Would I be able to replace this myself? Or maybe the whole board? Is there a way to test it?

Any gurus out there? I guess I am reluctant to spend $100/hr on a tech and whatever ($150?) in parts for a fridge that has run for almost 6 years straight for which I only paid $500 for?

Thanks in advance to any helpers.

Terry