AEG Santo fridge freezer not getting cold

A few days ago we noticed the fridge part was not cold,  the freezer seemed fine.  So after watching a couple of Youtube's I decided to look at repairing it.

I went straight to the freezer part and looked at the evaporator battery and the defrost heater.
The heater measured 183 ohms.

The next thing I looked at were the heater overheat protection switches (see below),  they seemed to have continuity.

I was a bit confused I didn't find anything so I put it all back together and switched it back on;   to my surprise the fridge got cold,  so the ice build up must have restricted the cold air flow up to the fridge.

Then the fridge alarm kept going off every few hours again even though the fridge and freezer were nice and cold.

So I decided to look to look a the fridge side of things. So I stripped that all down.

Not much to it to be honest,  a PCB which takes input from the control buttons and freezer temp conrol and some leds.

As this PCB on it's own couldn't control the fridge I looked elsewhere;  and I found a box at the back of the fridge near the compressor.

After opening the box I found the brains of the fridge and oh dear!!

Something had popped!

Turned out to be one of the Triacs;  as there are only two Triacs on the PCB one must be for the compressor and the other for the defrost heater elements.

So I took off all the electrolytic capacitors and tested those with my ESR meter and 2 were iffy;  so I replaced those.

Now, I'm not convinced that the Triac would fail like that;  so I've ordered a new heater element so I can test the ohmns reading, as I think* my heater resistance reading is a bit too low.

I put the fridge back together and it's up and running in a basic way at least; I also left out the overheat protection sensors as it doesn't need those until I fit the new Triac and heater when they arrive next week.


To be continued!