Daewoo FRS20 fridge/freezer problem

[juliusbben]

Hi all. I could use someones assistance.

Just for information, I am a trained technician but I have no experience in repairing fridges

I have a 10 year old Daewoo FRSU20 fridge/freezer. Few nights ago, the fridge stopped working, with a few "bang" sounds (coming from the top of the fridge) and then it stopped working; totally dead.

What I have done:

1) Replaced the glass fuse (A) on the controller board but blow again.

2) After some measurements, I could see that the diode D2 (B) in the power supply was shorted. I replaced the diode

3) When the fridge was turned back on, it ran for few minutes then turned OFF, but the fuse didnt blow. If the fridge was unplugged from power and connected again, it started but turned OFF again after few minutes. I noticed that the IC2 (STRG6352) (C) was overheating. It could mean the the IC was broken or some component was using too much current and the IC turned the power supply off to protect the circuits.

4) I replaced IC2 (STRG6352) with a new one. The IC over headed as well and burned over and the fuse (A) blew. I installed the old IC2 again, and the fridge turned ON but when back off after few minutes when the IC2 got too hot.

5) I unplugged most of the connectors of the control board. Only connectors plugged was AC power to the board and the display. The fridge turned ON and didnt shut down. However, IC2 was hot but under 100°C. When I connected the compressor, it ran for few minutes until IC2 got overheated and then turned OFF. I am sure that the problem is not the compressor.

Any ideas for me gentlemen and ladies

All my best

Julius

 

[debe]

First suspect is the capacitor ce2 22uf 50V, as its part of the power supply to the chip at pin4. I to doubt its a compressor problem as its switched on/off by a relay. Pretty sure its a powersupply problem.

 

[debe]

With just the mains & display connected also check diodes marked & the capacitors & voltages at C. D. E. Also that STR-G6353 is supposed to shut down when over heated.

 

[juliusbben]

I managed to fix the refrigerator. The problem was a broken 47uF, 400V capacitor, CE1. Thinking backward, I should have figure this out earlier because when I measured the DC volt on point B, I could hear a sound, coming from my VDC meater, and it implied a AC current. The bad thing is, my wife lost her patience and I ruched out to the next store and bought a brand new and shiny Samsung refrigerator. So, I have one newly repaired fridge to sell.

Thank you for your assistance.
jbb

 

[cowboybob]

Congratulations, juliusbben!

Sadly, your experience with the repair (undue external influence) is oft repeated around the world... .

I might also note that the voltage rating for CE1 (400VDC) is below what I would consider "adequate" for the task, given the nominal voltage at test point "B". Had there been enough space on the PCB to accommodate, for instance, a higher rated cap (5 - 600VDC), that's what I would have used.

Anyway, good job.

 

[debe]

Still its satisfying to have fixed it.

 

[cowboybob]

Indeed...

 

[juliusbben]

Indeed, I havent worked as a technician for many years (decades really so it was good to know I still have the touch to repair. I can honestly say this was fun.