One for the fridgies

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Originally Posted by scarry

Can't use an STC1000 in a frost free refrigerator,as it won't defrost,fan also needs to stop and start when needed.The coil will ice up and then it won't cool.
If you want to go that way,you need a low temp Dixel or Carel controller,which can be programmed for the defrosts,fan delays,etc.
And a coil and air sensor.
Cheapest and easiest option maybe to replace the PCB,or the FC(Food Compartnent) sensor if it is faulty.I would read the resistance ad see if it is similar to the Coil(defrost)sensor,they could be the same sensors.This may give you an indication if it is faulty.

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It does work, been using it since i wrote this post. Its a frost free fan forced all fridge, got a batch of lager fermenting in it at 12c.

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Originally Posted by loanrangie

It does work, been using it since i wrote this post. Its a frost free fan forced all fridge, got a batch of lager fermenting in it at 12c.

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Is the defrost cycle and heaters still operating?

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Originally Posted by sharmy

I have just come back from a fishing trip to Stanage Bay, while there some clown decided to cook some sausages and used a fishing knife to cut a couple off the string against the internal wall of my 80l engel. The knife cut a hole in the evaporator tubing and ,of cause, the fridge stopped cooling. Has anyone repaired this type of damage successfully without replacing the whole unit. Thanks in advance.

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In totally unrelated news police and SES are looking for a man that went missing on a fishing trip in the Stanage Bay area.

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Originally Posted by loanrangie

It does work, been using it since i wrote this post. Its a frost free fan forced all fridge, got a batch of lager fermenting in it at 12c.

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Sorry,i missed the All Fridge part of your post,i was thinking it was a fridge freezer....[bighmmm]

With a wide differential and operating at that sort of set point,fan running all the time,it should get a good off cycle defrost so you should be fine.[bigsmile1]

A technical question for the fridgies.

I was given a Brass Monkey 12v fridge a while back and it ran fine. However, recently it's blown supply fuses immediately upon switch on. I can't get it fixed under warranty by Jaycar because the lady who gave it to me tossed the purchase receipt.

Measurements indicate a short to ground on the positive line. Jaycar have no technical info on it (not unusual for Jaycar).

I pulled it apart and found the compressor is driven by an electronic control board. I didn't want to buy a replacement without further checks and this is where I'm confused.

The start and run windings both measure 0.1 ohm to common but info on the 'net only talks about DC resistance of mains powered compressors and suggest 12-15 ohms. The compressor is a ZH25G (probably generic.)

I don't think this is the whole story. I wonder if a DC resistance measurement is inappropriate and if I should be looking at AC impedance. I suspect the controller generates an AC power source from the 12v and, if the frequency is high enough, the windings will have sufficient impedance so as to not present a short circuit to the supply.

If this is the case, I'd be willing to buy a new controller. I doubt I can fix the old controller. I'm not even sure how one would test one.

So, I guess my question is - is the 0.1 ohm resistance OK? If the fridge needs a new compressor, I doubt it's worth repairing unless one is a fridgie.

It's highly likely the compressor is fine. The control board would have gone pop and may have dumped the incoming voltage directly across the compressor terminals, but the fuse would have saved it.

The compressor won't have start and run windings. If it's anything like most of the others it'll be 3 pins with 3 windings wired star or delta. So without a decent milliohm meter you're effectively measuring a short between all 3 pins.

Plenty of info on the net on the compressor you referenced. Random choice here : ToxicAntidote - 12v fridge rebuild

If your control box is like that one you may have luck repairing it. Highly likely it's one or more of the output stages gone short.

What Brad said is the go.

Do all three windings have the same resistence?
If so it points to the comp being OK,electrically,that is if it has no leakage to earth.

If the lady that gave you the fridge bought it on a Credit Card,using her statement,they may accept it is under waranty.

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Originally Posted by p38arover

A technical question for the fridgies.
I can't get it fixed under warranty by Jaycar because the lady who gave it to me tossed the purchase receipt.

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Whe I plugged my fridge into my Jaycar power bank, and it went POP, Jaycar had it in their system and replaced it on that info, without a receipt.

Tony

Just had a cruise around E-bay and there's a pile of control boxes for 12/24/48V dc fridge compressors for around $70.

Thanks Brad.

Yes, I'd found info on the compressor but nothing about winding resistance. I does have the standard 3 pins. A number of sites call them start and run windings, others indicate a star or delta configuration.

I had read the Toxic Antidote page but I wasn't going to do what he did. His controller board is completely different (except for connections). The control panel in the Brass Monkey is a separate unit.

Mine uses surface mount 078ROND N-Channel MOSFETs which aren't that expensive. https://pt.aliexpress.com/item/10050...yAdapt=glo2bra

I'm not sure how to check them just in case one or more is shot. I've never worked with surface mount components nor much with MOSFETs. I'll just look for shorts between the MOSFET pins.

AliExpress have the controller https://pt.aliexpress.com/i/10050060...yAdapt=glo2bra

(Dunno why AliExpress always returns hits in Portuguese.)

That page notes:

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Compressor Efficiency: The 12v variable frequency refrigerator compressor optimizes performance and saves energy.

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which is why I thought of impedance, not resistance.