T21 LCD questions regarding inverters, cable, etc

[cyborg]

I was lucky enough to inherit a working T21 with PIII800mhz , 384 MB ram, 60 GB hd, etc. The lcd screen would never power on. I tried it a few times but it was always a complete black screen. I didnt see any faint graphics, lights, or anything so this lead me to believe that it was the inverter and not a backlight CCFL issue. So i got a another inverter from ebay and when i installed it, everything was the same. No display. I even went and tried another 14.1 LCD from an hp and wired it up with the thinkpad and tried both inverters. Nada. So basically i tried 2 lcds (1 defintely works) , 2 interverters (1 suppose to be no doa) , and i still have no screen. Im able to plug in an external VGA monitor and everything works fine. What do guys think i can try next? I'm guessing i can try another lcd cable but i'd like to make sure i've done all the right steps. thanks!

[bontistic]

First make sure that everything is connected properly (connectors are flat against each other and no gaps). You might want to check your display settings on the BIOS as well. Also look very carefully, since the startup screen has a black background, it might be difficult to see that it is just very dim (thus prob with your backlight).

For the 14.1" T21, there are 3 types of LCD cables, 10 types of LCD panels and just 1 type of inverter card as you can see here.

You can check if you have to correct components to begin with as there are differences between XGA and SXGA+. We know for sure that your video chip is working properly. You just need to extablish what part(s) are not working. It can be anywhere between the motheboard route to the LCD cable connector, LCD connector on the planar, LCD connectors on the cable or on the LCD itself.

Another thing that you failed to mention is whether or not the LEDs mounted on the board work or not? LCDs are tough to troubleshoot because of the many factors involved.

[cyborg]

thanks for the response!
I checked pretty much most of the things you mentioned. Everything is tight and connected. All my components are the right ones but I just dont know which ones are the defective pieces. I'm going to get a spare cable from someone and test it. This way I'll have at least 1 of everything and figure out what's exactly broken.
You mentioned LEDs on the board and I'm not sure exactly which ones you are talking about. I had leds on the keypad itself (power, hd access, etc) and I also have leds for the battery charging, tv out, etc. (near the right hinge). Other than these two, im not sure of any other LEDS. Which are the ones you are talking about?

[RealBlackStuff]

The LEDs next to the Power button. They are mounted on the LCD cable, and visible directly when you remove the keyboard.

[cyborg]

Yes, those LED's do work perfectly. They are the same ones as I mentioned before regarding hd access, power status. etc. They are located on a board attached to the LCD cable.