Haier 50 Inch LED TV With No Power Repaired
Customer sent in this Haier 50″ LED TV for repair with the complaint of no power. The first I did was to plug in the TV in order to reconfirm that it was no power. After confirmed that it was no power I opened up the TV cover and focus on the power supply board. I checked on the main fuse first and it was opened circuit. Whenever a fuse got problem, it can be due to a minor surge thus replacing only the fuse can solve the problem.
If there is a shorted component that had drawn too much current beyond the fuse can handle, then the fuse will blow. Take a look at the two photos below:
I can’t simply replace the fuse and power it On, I had to check on other components first to really made sure no shorted components in the power supply board.
I used my newly bought digital multimeter and checked on the main component first (set to diode mode) which is the power FET and found that it was short circuited.
I proceeded to check on other components and did not find any other bad components. Below is the photo where I was checking on a 22 Ohm resistor and I got 22.05 Ohm which was good.
From the testing components in the power supply board, I concluded that it was only 2 bad parts…….the main fuse and the power FET. If you want to learn on how to check and test components, you can go to Jestine Yong website here.
I put in a 60 watt bulb in series with the main fuse and tested the power supply and I got good result. Take a look at the two photos below:
Conclusion- No power symptom in electronics equipment can be caused by only a broken fuse, couples of bad components, dry joint or even open circuit track. But in my case it was only 2 bad parts. Assuming after the replacement of the 2 new parts and there was still no power, I may need to check on the power IC (or replace it) or even the secondary side because a shorted component in the secondary side could draw lots of power causing the power primary side not to function.
Well, there are lots of possibilities or factors that can cause an equipment to malfunction and our job is to pinpoint and troubleshoot it till it works again. Will see you again in the next repair article!
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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Note: You may check out his previous post about Standby Problem In CRT TV Repaired