How To Repair Tadiran Air Cond PCB Board
In my area, especially in this time of the year, we usually get alot heat waves. People use their air condition a lot and many people who do not have air condition, will buy and install one. Facing such heat waves every year, will put a big load on old air conditions.
My friend, the air condition technician, brought me another air condition board for repair. It is completely dead, my favorite kind of repair cases.
I powered it up and I did not see any sign of life in this board. I did a fast check up on measuring AC voltage, checking the fuse and it seems like everything was in top shape.
It was very easy to open the case, two screws off and I could see the down side board.
I checked for cold soldering joints, any loose connection, again, everything was in top shape. This is the top side of the board and for the naked eye, everything was in order. I checked voltages at the main capacitor, there were 24 DC volts but for some reason, there was no relay click to indicate a live board.
I took the relay off and applied 24 DC power to it, it clicked and there was a continuity reading between the two pins. What could be the problem? So far, I could not see anything wrong with it yet, it does not work. I was getting power all the way to the secondary section of the power supply. Anything beyond that point was completely dead.
As you can see, I gave it a try and replaced the main capacitors although, it tested fine. The moment I did that, I started seeing the LED light comes on for a little bit then it fades away. That was a step forward and I started getting more hope to fix this complex board. I started checking the SMD parts in the lower side of the board and all checked fine. An idea came to my head and I thought of reflowing the entire SMD bard near the main IC.
There is no name on this integrated circuit and even if it was the main problem, I will not be able to replace the part. So, here it goes.
This is the flux that I use for re-flowing the SMD parts. I used this stuff a lot when I repair Iphone boards. This stuff is great but be careful when using it. You need to be in a good ventilated area to use that. After I was done, I let the board cool for a while because it was really hot. I plugged it in and to my surprise, it really worked.
Mission Accomplished.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.
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Note: You may check out previous post about fixing active speaker in the below link:
https://jestineyong.com/iphone-6-with-error-53-repaired/
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mohammed ali
August 7, 2017 at 4:12 pm
Hello Sir.
could you please explain how did you do the reflow?.
thank you very much.
Waleed Rishmawi
August 9, 2017 at 3:11 pm
Mohammed: I applied the flux past to the area where I need to re flow. I looked carefully when the pins of the ic start to get loose. I take away the heat and let it cool for a while. after done and cooled down, I clean with alcohol till is nice and clean. like said before, if you use the flux past, you need to work in a well ventilated area..or use a fume vacuum to take away the smoke from your breathing.
Parasuraman
August 7, 2017 at 4:16 pm
Handled an otherwise complicated case by wise application of technical knowledge and expertise!
Albert
August 7, 2017 at 8:49 pm
Thank you Waleed! Interesting to know that you also fixed Iphones with this reflux method. And if it was not the bad soldering of the chip that caused it failing to work, it maybe could have been the 64 pins chip itself that internally was restored after the hotfix?
Waleed Rishmawi
August 9, 2017 at 3:16 pm
Albert: for iphone re flow is a different. on this ic you could see the pins but on iphones, you cannot..you add flux and you take the ic off the board, you reball the ic and then use heat to put the ic back on board. in this case I re flow the ic till all the pins are shiny again. it was not an internal damage (lucky me) but actually cold soldering joints on that ic.
Robert Calk
August 8, 2017 at 12:42 am
Good job, Waleed. Sometimes a reflow is all it takes.
Yogesh Panchal
August 8, 2017 at 10:50 pm
Good Job! waleed
Meir .R.
August 18, 2017 at 3:11 am
Nicely done. I have tadiran with such control board at my own house