I have an old 17" LCD that works for about 2 seconds then turns off.
I tracked part of the problem down to a couple of dead flyback driver transistors on one of the backlight inverters.
I don't really want to wait 2 weeks to order some new parts and have a need to get it running this weekend.
I also don't have any transistors fast enough to hack up a replacement for the dead transistors.
So i figured it would be easier to just bypass the non working inverter since the LCD is bright enough with only one backlight working, but i need to solve the issue of it switching off after 2 seconds.
At first i thought it was just a feedback issue and the IC was shutting both inverters down when it didn't get one of the feedback signals, however i've bypassed that and it still wont stay on.
(It's a dual switchmode controller IC, TL1451
http://www.ti.com/lit/ds/symlink/tl1451.pdf)
So now i'm wondering if the design of the IC makes it impossible to run only one side of the chip.
Can anyone see if that's the case or not?
I'm also a little unsure how they are controlling the backlight brightness with a capacitor in series with each feedback input.Here is the circuit diagram of the LCD inverter board
The top half is running and displays a picture for 2 seconds or so, its the bottom have that blew up and seems to be still causing issues.
I have removed the shorted fets and checked all the power rails, it's definitely the chip shutting itself off.
![](http://psi.abcom.co.nz/lcdcircuit.jpg)
And the switchmode IC diagram
![](http://psi.abcom.co.nz/lcdcontroller.jpg)