ab CU-100 refrigeration unit trouble

[rlg]

I have a 4 year old ab CU 100 unit that is not cycling properly. The led gives the code for low voltage, 1 blink but I can get the compressor to come back on if I play around with the junction box and/or power wires. Sometimes the LED is not very bright. Of course I reconnected the power leads several times, they seem fine, but the problem feels like it is inside the junction box.
The leads are getting proper voltage and the batteries are strong.
Sometimes it will run for days without problem, sometimes hours. It does not make a difference if Im plugged in to shorepower or on the hook.

Can I replace the junction box?

When I first noticed it, the fan had stopped working but compressor was running. I believe it wasnt running long without the fan, a couple hours maybe. I cant be certain though. I replaced the fan with a spare I had, which now comes on and off fine with the compressor when the compressor is working normally. When it doesnt, and I get the dull blink, the fan will come on right away when I wiggle the connections and junction box, but the compressor takes more finesse to get to come back on.

Easy one right guys?

Thanks in advance!

[Bleemus]

Sounds like a possible resistance issue in the wiring. Have you run tests on each cable in the circuit?

[rlg]

Update

I received some info from resident expert Richard Kollman which will help me solve the problem. Apparently the fault lies in the junction box itself, an add on by Dometic who makes the unit. I will rewire the thermostat, power, ground, and fan directly to the controller as per Danfoss standards.

Thank you Mr. Kollman.

I will report back later with results.

Rob

[Bleemus]

You are in good hands with Mr Kollman.

[rlg]

You are right Bleemus!

Thank you Richard Kollman, all is working well now. The board has a mark like in your tech tips article 1, mine was on the ground circuit.

I tremendously appreciate your expertise and generosity sir! Thank you very much.

Regards, Rob

[Flyingriki]

I too have a C100 unit. Thermostat quit holding proper temp. Clicked in the knob at different places in the setting but was not reliable. I have a thermometer inside the box that reports to the unit on the wall to monitor temp.
Replace the thermostat and this one has no click at all in any setting and runs the box down to 31° without shutting off. Tried both ends of the knob sweep.
Is there a trick to installing the thermostat wire? It's in the same place as the old one and into the tube along the 11" x 18" cold plate.
Thanks for any knowledge!!

[Richard Kollmann]

Flyingriki, It does appear to be an Adler Barber power plate evaporator. If thermostat in picture is the new one it does not look like the type used by AB.

If I understand correctly the new thermostat no mater where it is set keeps compressor running all the time. Are you sure this thermostat is for refrigerator and not for a freezer?

Set the thermostat knob all the way counter clockwise. Then slide thermostats temperature sense tube and not the thermometer prob as for into the power plate tube as possible. After these changes compressor should stop running in less than 30 minutes. If compressor does stop turn knob slowly to the right (Clockwise) till compressor starts running again.

If it is possible to start and stop compressor now with this thermostat it may be possible to use it to control your desired box temperature.

[Flyingriki]

The thermostat is at the opposite side of box so I've stretched the sensor at far as I can behind the plate and down the side into the tube about 2" or so. Can't get any more. Nothing stops the unit manually. No click in the knob at any position. Sometimes I hear it go off but goes back on shortly after, temps vary when this happens. I specified the need for a plate thermostat for refrigeration only......not sure what I got yet. Will know more Monday.
C200 unit, by the way.