TCL 43s405 4k TV only runs on lower power mode. Sound like a capacitor issue?

[link626]

I've gone through 2 of these power supply boards.
Same issue on both. If I use TV at full brightness, full power, the screen will start blinking; go black once every 2 seconds.
It was fine for months before exhibiting this issue.


If I lower the brightness, and run it in low power mode, the blinking stops.

Attached photo below is the board.


Do you think this blinking is a capacitor issue?

These are all HEC brand cheapo caps, except the 82uF which is YST brand.
I cannot find spec sheets.


I desoldered all the caps from the board and measured them.

47uf measured 45.53 and 46.52
680uf measured 683 and 678
100uf measured 97.8 and 98.88
10uf measured 9.56
82uf measured 75.64
33uf measured 30.18


On the Hot side of the board, the 82uf cap differs most from its rating.

On the cold side of the board, the 33uf cap differs the most.

Would this blinking issue be from the hot side or cold side?


I recently bought panasonic caps to repair a pc monitor, and they all measured higher than their rating.
So this makes me suspicious of these cheapo caps.

[neilc6]

Re: TCL 43s405 4k TV only runs on lower power mode. Sound like a capacitor issue?

You are describing symptoms of bad LED backlights, not a bad power supply board.

[link626]

Re: TCL 43s405 4k TV only runs on lower power mode. Sound like a capacitor issue?

I doubt that, because when the tv first started blinking, I just replaced the power board, and the blinking was fixed.

I didn't touch the backlight strips.



Now 4 months later with the replacement (used) board, the TV is blinking again.

This board design/components must be defective, and the blinking probably shows up after 2-3 years.

[dick_barton]

Re: TCL 43s405 4k TV only runs on lower power mode. Sound like a capacitor issue?

Have you checked the capacitors ESR values?