TV electrical motherboard repair - Page 1
Forum section: electronics / repair

author: odell
author_rank: Contributor
timestamp: March 04, 2024, 01:16:14 am
content: I have a TV it's kind of old it was made in 2015. It's been working fine but all of a sudden when I go to turn it on it pops up the logo and turns the screen on then turns immediately off. I pull the motherboard out I don't see any blowing caps or anything like that but the board is a little dark like it got too hot could that have been the problem? should I just replace the motherboard or is there any way to repair it easily?

author: rsjsouza
author_rank: Super Contributor
timestamp: March 04, 2024, 01:43:10 am
content: In my experience repairing many TVs with a similar behaviour, capacitors can go bad without having anything visually obvious. I would start removing the three green capacitors near the diodes and testing them, moving to the smaller ones.Given they are relatively simple to desolder, it is the first line of attack.For some purists this might seem an unnecessary/unsophisticated method, but IME this covers a great deal of scenarios with TVs of this age, which usually are built to a cost and tend to have long and hot operation regime.Goos luck!

author: fzabkar
author_rank: Super Contributor
timestamp: March 04, 2024, 02:27:45 am
content: Disconnect the backlight and see if the TV stays alive.

author: mon2
author_rank: Frequent Contributor
timestamp: March 04, 2024, 03:43:55 am
content: Hi. While the fault may be power supply related, do consider to post the same details inside of the TV repair forum sub-section on badcaps. There are some true seasoned TV techs that frequent that board. Personally serviced a pseudo dead Hisense TV (horrible company). They are just known to die due to the wear out of the EMMC onboard. This wear out of the emmc causes similar issues. The EMMC cannot be replaced due to the complexity of the BGA device along with assorted hidden and locked keys for HDMI authentication, etc. Just a nightmare. Yes, a board replacement is a quick option if you can find one. Before you proceed, post full details of your TV set, serial #, etc. on the badcaps forum for more advice. Hope this helps.

author: MathWizard
author_rank: Super Contributor
timestamp: March 05, 2024, 02:49:49 am
content: If I had a DMM and the PCB, I would start testing parts on the PCB, without plugging it in. A lot can be found that way. IDK the OP or anyone's safety awareness level, but yeah a DMM with ohms, continuity, and diode mode, can find a lot without powering up the TV.Some cap, or diode, or transistor probably fried and popped a bit, IDK if resistor's ever make much noise when they overheat and fry, but some defect in them could allow gas to build up pressure and pop too I guess sometimes.

author: wraper
author_rank: Unknown
timestamp: March 05, 2024, 03:12:12 am
content: Does it actually turn off or just LCD backlight disappears?

author: odell
author_rank: Contributor
timestamp: March 05, 2024, 05:44:51 am
content: The TV turn off

author: Gyro
author_rank: Super Contributor
timestamp: March 05, 2024, 10:15:11 am
content: It may be just the angle of the camera and lighting, but I don't like the look of the soldering of the transformer pins and the thick wires of the axial rectifiers. They look grey and without a clean fillet shape. It may be worth re-soldering them.