Well the frig went out the other day. Got up in the morning and pulled out a bottle of luke warm water so I knew something wasn't right. A quick investigation revealed the heaters weren't getting any power. To save the food I rigged up some AC patch cords and a timer set to a 50% duty cycle. That being on at the top of the hour and off at the bottom of the hour. This got the heaters going again and provided enough cooling to save the food.

With that done, I had enough time to investigate further into the problem. If I couldn't resolve the problem the make shift heater power system would cover us for a couple of days to get a replacement board.


Should have been 2 oz copper on the power traces. Note burned connection at mid frame.

I pulled the control board to inspect and found the trace connecting the AC to the heater control relay was badly burned. An obvious open circuit and loss of heater power. I removed the board and unsoldered the relay. It's a 12 VDC coil with SPDT contacts. The microcontroller opens/closes this relay to supply power to the heaters. I tested the relay and it checked out fine. So I reworked the board by replacing the burned track with a short piece of copper wire soldered in place. A relatively easy fix. Reinstalled the reworked board, reset it and all is working now.

PC boards are available in 1 or 2 oz copper. 2 oz being the heavier grade of board. My guess is that Norcold used the cheaper 1 oz board which eventually failed due to resistive heating. 1 oz copper has more resistance than 2 oz copper per a given trace area. 1 oz boards are also cheaper and etch quicker. Last I checked Norcold wants some $650 for that board. After market boards like those from Dinosaur Electronics can be had for $180 + shipping. Go figure.

Single frame slide show HERE.