I have an MT60F-G4C Engel car fridge. At easter while the fridge was running on a 1kva Yamaha generator on the 240 v line I wanted to hook the 12v line to the auxiliary battery on the caravan. In a senior moment I managed to reverse the polarity - after a few minutes the smell of hot plastic alerted me to the problem. The inline fuse casing was melted but the fuse itself hadn't burnt out. After replacing the fuse and putting the polarity right the fridge continued to run normally for a few days but then began to cut in and out at short intervals and the fridge began to warm instead of cool. It did the same on either 12v or 240v.
After some advise from Engeland in WA (yes WA the 3 local agents have been spectacurly unhelpful not ringing back) and running some tests the compressor checks out OK falling into the specified ohm reading. The power supply is reading 20-21v AC which is above the specification recommended of 13-16v AC.
It only runs for very short periods of 2 or so seconds but tries to cut in again almost straight away.
I have had the power supply box apart and the circuit board controlling the current from the 12v input and reconverting to AC appears not too bad with the exception of the black wire coming from input to the board - it has been hot.
The only other thing I can see that is possibly wrong is 4 pairs of components I can only describe as black cylinders 2-3mm in dia. and 5-6mm long joined at the top by a connecting wire (bridge) as I said in twos. The top of these components may have got hot as there looks like a spot of glue on each one. They are the first components in both the red and black wires coming into the circuit board and are before 2 heavy diodes. Can anybody help with information as to what they do and should they look like this. I know a nes power supply is $365 - a lot when you are on the pension.
Any leads on which component may be failing would be helpful also the name of any technician that is clued up and doesn't want me to mortgage the caravan to fix this board would be helpful. Am going to try to attach photos of board. 

Have PM you Mezza. Daryl    Just for other peoples info the objects are L7 & L8 which are 2 ferite beads threaded on a single strand of wire. Diode ZD4 is a zenner diode, check that & diode alongside for shorts, solder joint betwean diode looks iffy. Also check other side of board with a good magnifying glass for faulty solder joints.

-- Edited by DeBe on Saturday 24th of April 2010 11:36:16 AM

hi debe i hope you can also help me as i have a waeco 35lt which was on generator and did the same thing. it had a power serg i think as the next door person tipped the generato over to see how much fuel was in it and the generator nearly stopped and when he put it back down it picked up revs and then a great clowd of smoke. the fridge had no power at all not happy. i took it to the shop and they said something about the power supply or something .i didnt really get much of an answer.would it be easy to fix even if i can get it to work on 12v. could you please help regards possum &yvonne

Hi Possumyvonne Iv only just got back from Mudge. What model is the Waeco is it a CF-35? & doesit still run on 12V ?  Daryl

Hi , Just a few lines on engels, Have fixed a few and when the power suply is giving trouble , most times its the motor that is the problem, it will be useing more currant than the suply was made for..the best idea before replaceing the suply is to see how much amps the motor is pulling,, You need a clamp meter and it has to be on AC AMPS. Put the clamp on one of the wires that go to the motor..the engel should not use any more than 2-3 amps when first turned on and will drop down to 1 and a half after a while.. The suply that is showen is a ps249 and very had to fix ..No I dont fix engles ..Bob

Sorry ... .didnt read the post properly. A 60lt motor will pull 4-6 amps on start up .. the supply will be a sp202? If the motor pulls more than 6-8 amps it will give you trouble again if you just replace the supply ..Bob

thanks bob - have tried to get a reading with a dick smith multimeter by putting it in the line from the power supply to the compressor. I am only getting a reading of .18 amp. Don't know if that can be right. The voltage is reading within the range specified.
Thanks - mezza

power supply is an SP-306C. thanks -  mezza

Hi mezza , the engel motor runs on AC power, and wont show on the amps as most dicksmith mm dont have AC AMP unless you pay a little bit more for them...the sp306c is a late modle one.. havent had one in to see it yet...I have a few power supplys for engels but not one of them..the early ones were a easy fix..now its all serface mounted stuff..sorry i carnt help any..Bob

Thanks to all the people who have been helping. Finally bit the bullet and took the fridge to local Engel repairer who diagnosed the compressor side of the fridge as the problem. Many $ later I have the fridge back hopefully for more years of work. It must have been a coincidence that the compressor gave up after the power problems. I had noticed that there was a vibration noise prior to the fridge giving up and had put it down to the condenser rattling at its extremities. The technician said that there was a blockage on the high pressure side and the compressor was drawing over 4 amps. Anyway thanks guys.

Good to see your fridge is back in business.