WAECO CF40 fridge dead on 12V, good on 240

Chrs_tof · Member

RE: WAECO CF40 fridge dead on 12V, good on 240

DeBe · Guru

Definitly should not have 12V on the 5V side of the reg. With 12v it would damage the display board.

Chrs_tof · Member

I didn't check the mofset for 12v I only checked for continuity. I'll check what voltage I have at the 5v pin tonight.

Chrs_tof · Member

Hello chaps, My apologies for my delay in getting back to you. So I do not have continuity between the REG GND and pin c. I am getting 12v at pin c when the board is powered up by 12v. The only pin with continuity to the REG GND is the middle pin on the MOSFET. not too sure where to go next. Regards Chris

DeBe · Guru

Try running a small lead from the Reg middle pin to a separate known ground (neg) point. If the middle pin on a 3 term reg isnt grounded then they dont work, usualy the voltage will be too high on the 5V side.

Chrs_tof · Member

Just tried that then and it sparked. I tried earthing out on the negative post on the danfoss board also tried on the negative post of the battery. All 3 pins of the mosfet seem to have 12v.

DeBe · Guru

I am refering to this board & the 3 term 5V Regulator. I think we are discusing a diferent board as theres no MOSFETs on this one. WAECO CF-40AC. PCB.2 (1).jpg

Chrs_tof · Member

Ok so I tried providing a separate earth to the reg and still no change. I removed the reg and tested it on the bench and worked as it should. I resoldered the reg back to the board but only the 12v and 5v pins and kept the negative pin out and ran its own separate earth not through that board but back to the negative on the danfoss 12v supply and still no good. I started to disconnect plugs just out of curiosity. Once I disconnected the cable for the display the reg worked as it should. 12v on one side and 5v on the other. Is it safe to assume something on the display board has failed or corrupting the other board?

DeBe · Guru

It does sound like theres a problem & back feeding 12V from some where.

Muskat55 · Veteran Member

Useful thread, it has convinced me never to buy a Waeco product

Chrs_tof · Member

The whole 5v side of that board has 12v running through it. I've just plugged everything in and now the 240v doesn't work.

jameswrowe · Member

Hi I know this is a very old post, but hopefully someone is still around. I have this exact problem with my Waeco coolfreeze cf50. It runs on 240v. However, when I switch over to 12v it comes on for 2seconds, then the display cuts out and the compressor doesn't kick in. I have done the above, ie, connected to 12v, checked for 12v reaching the unit, bridged c+t, the compressor kicks in and the fridge runs. Although the display shows a continuous error light and the display half cuts out. I have 12v and 5v across the two points mentioned above. This is how the display looks while running with c+t bridged......

The [power light flashes once every 4 seconds

-- Edited by jameswrowe on Monday 5th of July 2021 07:02:43 PM

-- Edited by jameswrowe on Monday 5th of July 2021 07:34:05 PM

DeBe · Guru

Does the display panel light up correctly when its running properly on 240V?

jameswrowe · Member

Yes it does. All runs correctly on 240v. Display on, no errors and down to temperature.

DeBe · Guru

DANFOSS, 101N0500. CONTROLER (1).JPG I am asuming your compressor controler is a Danfoss 101N0500 as in picture? When operating on 12V is there 12V on pin A+ & C-- ? There should be voltage there even when the compressor is not running as this power for the display/control board.

jameswrowe · Member

Hi, I've just checked and there is 11.88V

jameswrowe · Member

there is 12.9v across the battery
11.88v across the two points on the circuit board
11.88v across the A and C points as mentioned above

DeBe · Guru

I would suspect theres a problem with the display board.

jameswrowe · Member

Many thanks for your reply.

I will try and track down a replacement and let you know how it goes.

Regards

DeBe · Guru

See them on Ebay for around $108.

Magnarc · Guru

DeBe You are to be commended on the way that you have helped Crusa and the others. You obviously know what you are talking about. A special mention must go to those on here who refrained from offering "advice" and let you do your stuff.

These sort of posts are what forums like this do best, such a change from the bickering and playground name calling that some posts degenerate into.

Dicko1 · Senior Member

Magnarc wrote:
DeBe You are to be commended on the way that you have helped Crusa and the others. You obviously know what you are talking about. A special mention must go to those on here who refrained from offering "advice" and let you do your stuff.
These sort of posts are what forums like this do best, such a change from the bickering and playground name calling that some posts degenerate into.

Too right!!!