820-00138-a No backlight, driver fine

[MexicoTV]

Hello all,

I'm having a bit of a hard time fixing this board due to the lack of board view and the less than common issue (for me). Boots up fine, screen is working, just no backlight. When I measure pin 1 of the LVDS connector I get no attempts of producing voltage. There is 5V getting to the chip.There is no enable signal arriving to the chip and no attempt at producing enable signal. When I measure using diode mode on pin 1 of LVDS I get about 1.1V drop. There is no liquid damage.

 

[2informaticos]

First of all, try known good compatible LCD assembly.
You can test with cracked one, if has good backlight for sure.

 

[MexicoTV]

Does the LCD panel have to be attached for it to fire up? I've been testing without the panel attached this whole time. First time encountering non short or corrosion related fault. Is this why I get no enable?

 

[2informaticos]

Ooops, why do you expect LCD output enabled without screen connected?

 

[MexicoTV]

The backlight LED pin read short to groundand screen cable was a bit fried. Was not repaired as customer didn't want to buy the lcd. For some reason thought the driver would still try running without the LVDS there. Good to know.