Toshiba 50L1400U Back light cycling On and Off

[kudalski]

Back light on this TV model cycles ON and OFF about 2 second intervals only when signal is connected and I got picture (As back light goes bright).
But when TV is idle with no signal (Back light dim) back light stays ON steady and does not turn ON and OFF (cycling)
When signal applied, back lights brightens up and it begins to cycle on and off. Pls help. thank you

[dick_barton]

Re: Toshiba 50L1400U Back light cycling On and Off

Turn the backlight down as low as possible in the menu and see if it stays on longer. Probable led fault.

[ReeceyBurger123]

Re: Toshiba 50L1400U Back light cycling On and Off

An Led is on the brink of failing open or shorted, best open the panel and change the Led as it will drop soon.

[nwcs]

Re: Toshiba 50L1400U Back light cycling On and Off

I just fixed this exact same problem on two of these TV's. I found that U901 on the power supply under a heatsink is the issue. I remove the top heatsink and the IC then clean the old thermal compound and replace it. Ran both TV's for hours this way. I have even put a vga cooling fan on the heatsink and soldered the positive wire to pin 1 of p802 and the negative to pin 4.

[dskall]

Re: Toshiba 50L1400U Back light cycling On and Off

https://www.youtube.com/watch?v=FSzF2TJh20A