Norcold de-250wal 12v problem

Hi. I have a norcold fridg that work on 12dc and 120 ac , but de is to stop work on 12dc yesterday , somebody can told me why and whitch part need to be remplaced ?

,,,,did you check if the fridge is getting 12 volts to it and if a circuit breaker tripped or a fuse blew,,,,

Yes. 12v on the terminal in the back. It make that last year , run fridge 1 night on 12v. On morning , nothing work. I connect 120v, put switch on AC and fridge restart . 2-3 days later I try on 12v and fridge work again. So all was ok ! But problèm came back this week end ! I see an electric diagram that show. The thermostat have 3 wire , 1 commun , 1 for 120 and 1 for 12v, so maybe the thermostat is the problem ?

I can't see a breaker or fuse on the fridge . I will take out the fridge on a table to see

I had a friend with a norcold he was having trouble with on his boat. Cooler style, 120/12v. I looked at it for him and iirc, the problem was with the 12v cord connection socket. His did the same thing, would work on 120, but not 12v.

I chek And i have 12v on the black and red pole behind the fridge . I chek thermostat and have only 2 wire, so it's not a thermostat whit 120 and 12 circuit .i dont know what To chek
V

You got a wiring diagram? The way most AC/DC fridges work is that the 120v side is transformed to DC 12v when in AC mode. So if it's working on AC, chances are the problem is somewhere between the DC power input and the ac/dc toggle switch. B/c even in AC mode it's running off 12v DC from a transformer internally. So that tells you that the 12v compressor and thermostat and contactor/relay(if there is one) and any other fans, controls etc that make the fridge function are in fact working.

But.... that's an old unit if it's made in Japan and has R-12 in it. They don't make them like that anymore, it also means the control scheme will be fairly simple and straightforward. But it also may mean that it has a compressor that runs on 20v/50Hz AC and a special DC inverter to take the DC side to 20vac @ 50Hz and a transformer to take the 120vac/60Hz to 20vac/50Hz. If that's the case you may have a problem with the inverter, and if so you may be screwed if the problem isn't obvious.

Yes.  Its made in japon!  We can see it on the plate ! And I see à motor that is write 6-20v on it.

marco_chevy wrote:I see à motor that is write 6-20v on it.  

6-20v AC or DC? Is the compressor made by Sawafuji? I'd still check DC power to the inverter and make sure it's getting there. The fact that it ran intermittently on DC still may point to a bad connection or switch issue.

Ok.   I let run the fridge on ac  last night and all the day.  When chek this evening , fridge was cold , all was ok.  I open door , wait the fridge restart , and it restart normally after about 30 secondes .  I switch to 12v and it stop working .  But after 20-30 seconds , it restart on 12 v !!!    Very strange .  I stop , put on 120v , return to 12v and work again.  Now its working since 30 min correctly .   I touch nothing !   Like it have a contact somewhere that is not clean on 12v , or not enough to start .

I also remarked , when switch from 120 and 12v , I can hear a difference .  The sound is not the same , not a big difference but it have one.  But its have a difference since I have it .  Its mean that is not the same hz ?  Or same voltage ?  Its the thermostat or the switch that can have a bad contact on 12v ?

After some test , i took V on switch and found 2 wire that have always 12.5v ( input ) and 2 other that have always 120v enter the switch , and found the out that go to compressor , it have 0 when thermostat is close , and 14.00vdc when I turn on thermostat on 12v switch , and 20v if I change switch on 120v . So the sound change because it switch from 14 to 20v . On Dc, may be amp are more , so the switch or thermostat have a bad contact ! Its work nice on 12v since more than 1 hour , 3-4 stop and go and work again . Hard to understand !

OK so it is a sawafuji and it does run on 20v, but 60Hz, not 50 according to the label there. You should have 20v AC to the compressor, whether it is on AC or DC. There is an inverter in that box that converts the 12vdc to 20vac. If that isn't happening, it isn't going to run right on DC. That compressor relies on and is tuned to the resonate frequency of 60Hz AC current to vibrate properly and function.

http://www.sawafuji.co.jp/english/tech/shindou.html

Its 14 and 20 v DC that I can read whit my meter !!! I will recheck but was DC between 2 wire only when compressor running !

Is your meter auto? If not, set it to AC and take a readings.