Electrical fault EvaKool 65 litre fridge/freezer

[kryg]

I’m trying to trace an electrical fault, having checked out my Australian build EvaKool 65 litre fridge/freezer. There is a short as it trips the boats 16-amp 12 v. fuse. Also, when I tested it on 240-volt power the lights flash every second for 5 seconds which is not as per trouble guild. The compressor nor the fan will start up. The only indication of power is the light lights when connected to 240 volts.
The wire power plugs are not shorting, what could it be?
Does anyone know what else should I check or replace?
Attached are photos of the compressor and wiring.

Thanks, any experienced input is most welcome.

[OzeLouie]

Suggest taking note of where each wire is connected to the MDM (Black box!) Perhaps a picture or two. Remove all wires except the thick power supply red and black going to - & + at the top. Remove red and black from that other small black gadget and apply 12VDC direct. Put a link between C & T then apply 12 volt supply as normal. If the compressor then starts and runs ok this will determine if the problem is the MDM or elsewhere. BTW suggest protecting pipes from rubbing through where they appear to have contact with the vibrating compressor, perhaps use silicon to anchor. (Specially the thin capillary)

[kryg]

Many thanks, OzeLouie, for your guidance. I did remove the MDM wiring except for Power and connected the C to T with a single wire as you recommended, Result once again the fuse tripped off. I guess the short must be somehow be the MDM or the compressor as it will not run? What do you suggest the issue is? Thanks so much for your help.

Originally Posted by OzeLouie

Suggest taking note of where each wire is connected to the MDM (Black box!) Perhaps a picture or two. Remove all wires except the thick power supply red and black going to - & + at the top. Remove red and black from that other small black gadget and apply 12VDC direct. Put a link between C & T then apply 12 volt supply as normal. If the compressor then starts and runs ok this will determine if the problem is the MDM or elsewhere. BTW suggest protecting pipes from rubbing through where they appear to have contact with the vibrating compressor, perhaps use silicon to anchor. (Specially the thin capillary)

[OzeLouie]

Originally Posted by kryg

Many thanks, OzeLouie, for your guidance. I did remove the MDM wiring except for Power and connected the C to T with a single wire as you recommended, Result once again the fuse tripped off. I guess the short must be somehow be the MDM or the compressor as it will not run? What do you suggest the issue is? Thanks so much for your help.

But did it still trip your breaker? Provided the supply (thick black and red) were not connected to anything other than the MDM and it still tripped then most likely the MDM is shot but to be sure do this:
Remove MDM, (undo screw and rotate a little CW) Unplug from compressor. Power up again and see if it still shorts out. While available use a multi-meter to read motor windings, there should be approx 2 ohms between any two of the compressors three motor winding pins and zero (open circuit) between any of those 3 pins and the compressor case. Highly unlikely to be the actual compressor.

[kryg]

Hello OzeLouie,


You're correct, Thank you! The MDM has failed. The Compressor is as predicted in your instructions. ok, there is a resistance is on all 3 pins. And zero when grounding per pin. Question see attached MDM. Do you sell them if so because of your great support I would like to return the favour and purchase one from you. Please let me know how best to do the transaction.. Once again Thanks for much, see attached photos.

Originally Posted by OzeLouie

But did it still trip your breaker? Provided the supply (thick black and red) were not connected to anything other than the MDM and it still tripped then most likely the MDM is shot but to be sure do this:
Remove MDM, (undo screw and rotate a little CW) Unplug from compressor. Power up again and see if it still shorts out. While available use a multi-meter to read motor windings, there should be approx 2 ohms between any two of the compressors three motor winding pins and zero (open circuit) between any of those 3 pins and the compressor case. Highly unlikely to be the actual compressor.

[OzeLouie]

Pleased to help but unable to supply that brand of MDM. Secop 101N0220. Suggest try Jeff at Sydney Marine Refrigeration 0410 522 611 or check out EBay!

[kryg]

Many thanks to your guidance and effort - as a result I learned a lot about fridge compressors troubleshooting diagnostics something I never ever considered before. As the saying goes - Yesterday is the past tomorrow is a Mystery today is a Gift that is why it's call Present!

Originally Posted by OzeLouie

Pleased to help but unable to supply that brand of MDM. Secop 101N0220. Suggest try Jeff at Sydney Marine Refrigeration 0410 522 611 or check out EBay!

[sinnerman]

This is a real simple system. These compressor units are used EVERYWHERE includin home units and trucks/campers...

You have a 12 volt compressor, a controller which runs converts 24v to 12 volts for the compressor, (some controllers can run on AC 120volts as well). The controller also controls the compressor speed and the cooling fan.

The thermostat in the ice box is basically a "switch" which tells the compressor (via the controller) to turn on and off depending upon the temperature...

TO troubleshoot, disconnect the 12/24 (+ / - ) terminals (top two) from the controller box. Turn on power to unit and see if breaker trips. If YES, problem is a short in the wiring before the unit.,

If not, reconnect the +/- wires, and disconnect the controller box from the compressor. To do this, TIGHTEN the screw (turn clockwise) on the front of the box (the screw next to f the "C" terminal). Tilt the front of the controller to the LEFT to remove it.

Here is a video showing you how to do it (you can jump to 1:15)

There is a single electrical connector (3 pins? ) between the controller and the compressor. Disconnect the connector from the compressor (pull off). then fire up the system again to see if CB trips. If YES, then you have a bad controller. Bad controllers are common.

If not , then the compressor may be bad. Here is a video on how to check the compressor for shorts/opens:

https://www.youtube.com/watch?v=-PjBHEgAK18

Cheers.

[sinnerman]

Here is the video showing how to remove the controller. (at 1:15). I deleted the link accidentally from my previous reply...

https://www.youtube.com/watch?v=KUicJmeLxCc

Cheers

[kryg]

Hi Sinnerman, Many Thanks - Just what I was looking for! Very helpful link.

Originally Posted by sinnerman

This is a real simple system. These compressor units are used EVERYWHERE includin home units and trucks/campers...

You have a 12 volt compressor, a controller which runs converts 24v to 12 volts for the compressor, (some controllers can run on AC 120volts as well). The controller also controls the compressor speed and the cooling fan.

The thermostat in the ice box is basically a "switch" which tells the compressor (via the controller) to turn on and off depending upon the temperature...

TO troubleshoot, disconnect the 12/24 (+ / - ) terminals (top two) from the controller box. Turn on power to unit and see if breaker trips. If YES, problem is a short in the wiring before the unit.,

If not, reconnect the +/- wires, and disconnect the controller box from the compressor. To do this, TIGHTEN the screw (turn clockwise) on the front of the box (the screw next to f the "C" terminal). Tilt the front of the controller to the LEFT to remove it.

Here is a video showing you how to do it (you can jump to 1:15)

There is a single electrical connector (3 pins? ) between the controller and the compressor. Disconnect the connector from the compressor (pull off). then fire up the system again to see if CB trips. If YES, then you have a bad controller. Bad controllers are common.

If not , then the compressor may be bad. Here is a video on how to check the compressor for shorts/opens:

Cheers.