Any fridge mechanics in here.

[CoopsOz]

G'day all, my bloody fridge has packed it in again. It's not defrosting properly....I don't know if it's the ceramic heater, the PCB or just the defrost relay (which I think is on the main PCB anyway). I was hoping someone has access to the LG service manual site and could do me a favour.

The model of the fridge is LG GR-B207EC.

BTW, the heater is measuring 255 ohms...does that sound right?

Here is the PCB....is it possible to pick the defrost relay on the board?


TIA
Coops

[Hack]

That board looks like it would be easy to swap out. If I was sure the problem was there and another could be found for a reasonable price that's what I'd do.

[CoopsOz]

reasonable price

I haven't seen reasonable prices for years! I betcha I swap out heaps of shit before I get it working properly again...it is still cheaper than a new fridge though.

[new_moonshiner]

what about the heater high limit ?

[scotty]

what about the heater high limit ?

yep if it is stuck open then no heater


does that baby have a timer on it?????

[alice]

Ask FB on Austech, he'd know....

[new_moonshiner]

yeah i mentioned the terminating thermostat to see if he had checked it . youre right if its stuck open no power to heaters , the board has the timer incorporated into it so there is no electromechanical timer like most all the older ones had ..seems more and more things going SS (solid state these days..

[CoopsOz]

The fridge is finally fixed! I'm going to explain what was wrong just so anyone who stumbles onto this thread in the future knows how to fix their fridge. I hate following a thread when I'm working on a problem only to find it just stops without a result.

I'll start from the start, the fridge is a electronic fridge which blows air from the freezer side into the fridge side. What was occurring was the evaporator was icing up to the point that it was blocking the inlets to the fridge. After gaining access to the evaporator it was very evident.

With no experience (and no CCT diagram) I attempted to rectify the fault by trial and error....I replaced the entire motherboard ($150.00) and the fault continued. I then replaced the heater sheath ($100) with exactly the same results, needless to say I was getting a little pissed by this stage!

After countless hours on the net I did manage to find a CCT diagram for the fridge....low and behold there was a thermal fuse placed between the heater relay on the motherboard and the heater itself. I had incorrectly assumed the heater was getting power because I had metered the relay with the full 250v being read.

The problem was the bloody thermal fuse, this is physically attached to the evaporator, it's job is to go open circuit once it reaches a pre determined temp (in this case 72 degrees C). It is my understanding that the relay operating the heater is on a timer...it pays absolutely no attention to what the fridge itself is doing. The relay will quite happily pump out power for the pre-determined amount of time, the fuse is there to (obviously) cut power in the event everything gets too hot.

In the end I have spent over $250 and many hours on replacing a $3.50 part. I know many people said check the fuses, but I was looking for a traditional fuse....not a thermal fuse!

I hope this can help someone in the future. BTW, this entire post will be cut onto other forums where I was asking for help in order to tie up loose ends.

[new_moonshiner]

Glad you got it going ... we call them terminating thermostats here ...