Darn need help guys samsung ln-t4042h 24v backlight problems

[budm]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

OK, that means the PS_ON signal from the main board may be going high and low, please monitor that signal line. If it does, then the problem is more likely to be in the main board.
You can read my guide to understand how most LCD TV works.

[davewilson61]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

no picture ...backlight just goes on and off with the relay

[davewilson61]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

ok if you le it set for a while just sits threre ok push power button on front it play a melody and turns on then off then on over and over...then press power off button plays a different melody powering off...and its off

[davewilson61]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

its seems normal...just goes off and on by it self ,,till you manualy turn it off

[budm]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

Try disconnecting the LVDS cable which is the multi wire cable between the main board and the T-CON board, also you need to monitor that PS_ON PIN voltage.

[notallbad]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

Quick question for budm etc...
What symptoms would a faulty keyboard, front button panel board, have if the buttons were sticking on?
Wouldn't think it would be related to this thread but just wondered.

[budm]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

If one button stuck close, it will lock out the other buttons.

[davewilson61]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

ok dont have a PS_ON anywhere have DIM on cn1803 and POWER on/off on cn801
checked them got with backlight on 3,3v on dim and 3.3v on power on/off
backlight off both have 0v
now unpluged t-con board no change same on dim and power off/on

[budm]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

The PS_ON must be toggling high and Low in sync with the relay clicking on and off, it cannot be sitting still.

[davewilson61]

Re: Darn need help guys samsung ln-t4042h 24v backlight problems

it is changing from 0v to 3.3 with relay