Dometic Fridge - Generic board problem fixed
Although this happened to a Dometic refrigerator, the root cause could occur on any electronic appliance.
Symptom: Fridge was working perfectly. Pressed the On/Off button to turn it off. A few days later, pressed the On/Off button to turn it on and no result. No lights on the panel, no refrigeration.
Procedure: Checked the fuses on the rear panel. Both were good and both 12VDC and 110VAC were present. Removed the upper control board (buttons and LEDs), removed the connector and used a pair of sewing needles with the meter to check voltages on the connector that comes from the lower control board. Pin 2 (orange) showed 12VDC. Suspected problem could be in the upper control board.
There are some fairly in-depth troubleshooting manuals online if you search by manufacturer and model number. They offered insight into the process, but they did not lead me to the root cause.
Called Dometic for assistance. Spoke to a sales person who had a very basic knowledge of the circuit boards involved. She was able to look up the replacement part number and quote a price, and yes they could sell it to me directly, but no, I could not pick it up in person. Even if I was standing on their doorstep, I would have to pay them $25 to have UPS deliver it to the campground down the street. No, they do not allow their technicians to talk to customers, only dealers, who I would have to pay to look at the problem. Dometic are quite determined to stay at arm's length from the great unwashed who are paying thousands of dollars for their products. A most unsatisfying customer service experience.
Now it was a matter of principle. I was determined to avoid handing over the money for such poor service.
On closer examination, this appeared to be a simple board with some LEDs, buttons, and a couple dozen discrete components. There were a few fine cracks in the varnish coating over the copper traces. A couple of them were showing small green blooms of copper carbonate. I used the meter to check for continuity between the solder points at either end of the suspect traces. The copper trace leading to the On/Off switch showed open. I soldered a wire between the two solder points to bypass the trace and problem solved. I cleaned and coated the remaining cracks with clear nail polish.
We are no longer stopping for bags of ice to stock our 'ice box'. It was losing its olden-days charm anyway.