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
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Yogesh Panchal
March 28, 2022 at 5:40 pm
Good Job! Suranga
Congratulations! for new Multimeter.
Suranga Bandara
April 2, 2022 at 1:45 am
Thanks Mr. Yogesh
HtetAung
June 3, 2022 at 8:47 am
Thank your brief article
Ajay Kumar, Puducherry
March 28, 2022 at 6:57 pm
Nice job, well illustrated.
Albert van Bemmelen
March 28, 2022 at 7:30 pm
Good that you first checked for shorted parts before replacing the power fuse! And nice that you showed your new 9999 counts DMM. Looks like a good quality meter. Never a bad thing to have extra measuring equipment.
Suranga Bandara
April 2, 2022 at 1:47 am
Thanks Mr.
Suranga Bandara
April 2, 2022 at 1:48 am
Thank you very much..!
Mr Albert.
Parasuraman S
March 28, 2022 at 9:03 pm
Methodical troubleshooting! Well done, dear!
gary cale
March 28, 2022 at 11:06 pm
Smart move to look for other bad components before replacing fuse. Good job!
Mathew Charles Karonga
March 29, 2022 at 11:36 am
Thank you for this article
will borkmark it for future reference,
Well done in ressurection of yet another piece of of equipment that would otherwise been dumped
Thando Mavimbela
March 29, 2022 at 6:06 pm
Tnx so much Sir ...l appreciate your knowledge...I was knowing nothing but am something...May God bless..you
Suranga Bandara
April 2, 2022 at 1:50 am
Thanks Mr.
Tayo
March 30, 2022 at 1:37 am
Its actually refreshing to see an newer model LCD TV actually being repaired for once. Most issues with the newer TVs relates to its display panels which are for the most part not feasible to repair. Its crazy to think that a TV's power supply and logic board will likely outlive its display panels!