DIY Refrigerator repair

My long time loyal refrigerator suddenly refused to cool anything down to below 32 degree Fahrenheit. It was beginning of June 2013 and temperature started to raise. We were thinking of getting a new one since this one was over 15 years old. However it turns out that buying and deliver it to the right time when some one be at home is going to cost us more than a week and we still have lots of food which needed to be kept frozen, therefore immediately fixing it sounds better solution than buying one.  

I thought to give it a try. First I did some online research on how the refrigerators function and their maintenance. I came to know it is common for refrigerators that has a defrost mechanism to not to cool anymore if the excessive ice is build up on it's coil that the defroster failed to defrost. Due to those ice my upper portion of the refrigerator was able to cool down to 32 degree but the buttom portion was not able to cool down that much, the temperature was over 65 degree (I measured using my temperature gun that uses laser technology). Because the cold air was not blown, the refrigerator never was out of the defrost cycle as the ices were built up on the coil and obviously the defroster failed to melt it. An youtube video gave a very good detail of what I needed to know. 
This was a Norge Refrigerator on the top right.
The interior look like the picture below.

I start dissembling the fridge. Doors were easy to take off, however one of the screws that kept the middle segment cover refuse to loose no matter how I tried. I sprayed some WD-40 and had to wait for a while to loose this one and finally I was able to get to the middle section where the coil resides. Here are the pictures and the description of the steps I took: 
Step 1: I took the doors off
Step 2: I had to loose extra two screws that were covering the temperature control unit. that looks like the picture on right.
Step3. After get the cover off, I pull the controller and It came off like a drawer. you can see how it will look like on the picture. I saw a thick layer of ice covering the cooling coil.
Step 4: I started to crash the ice gently using a kitchen knife, but that was an idiotic act, as I realized I could easily melt them using hair dryer
    Step 5: I started using hair dryer, then I thought of using warm water, and it turned out to work faster than the hair dryer.

 Step 6: I was getting impatient as the melting process was taking too long I used hot water, after melting significant amount of ice I was able to remove the foam cover on the top of cooling coil


Step 7: Still lots of ice to remove, repeated the hair dryer, crushing and throwing hot water couple more time finally it was clean enough to see the cooling coil and the defrost coil seating inside the cooling coil assembly (Picture on right)
Step 8: I found that the one end of the defrost coil is severely corroded, in order to make sure the defrost coil is intact I used my digital multimeter and it shows the continuity between two ends. I re connect the corroded end with electrical tape and put the defrosting coil back where it was.   

Step 9: Start assemble all the parts that I dissembled. 
Step 10: Start the refrigerator and after a few minute I hear the cooling chember started blowing the cold air again, happy end of my measurable story.

Tips: To avoid this situation, you should always make sure your refrigerator is not overloaded and always have enough space to circulate the air. Also don't forget to clean the rear of your refrigerator and vacuum the air filtration compartment.
Thanks for reading.