Hello,

I'm trying to diagnose a black screen issue on a T42 type 2373-CWG, with a 14'' screen.

Here are the symptoms:
- screen totally black
- fan running
- battery and "power on" diodes light up
- no beep, even when the two RAM sticks are removed

I exchanged the Intel CPU chip, main battery, CMOS battery, hard drive and keyboard/touchpad panel with those coming from a working T42 (2373-3YG) in order to see if one of these components was at the origin of the problem.
I also tried removing the CD enclosure.

I also connected the serial port to an external monitor and pressed "Fn + F7": no result.
(Is there something more to do to connect an external monitor?)

Inside the notebook, the cables seems correctly connected.

I tried pressing the notebook enclosure near the touchpad, because I had heard about the flexing problem. No more result.

Now, is there a way to diagnose if the problem comes from the GPU, from the motherboard or from somewhere else?

Thank you very much.

A board that doesn't beep with RAM removed is most likely - as in 99.9% - dead.

Start shopping with a new one.

Hello,

Thanks for the answer, but I dislike throwing whenever possible, and decided to go as far as I can to find from where does the error come from.
Maybe is the GPU not correctly soldered or something similar.

I unmounted the motherboard.
Here are commented photographies the recto and the verso of the motherboard:
http://imgur.com/93XP2
http://imgur.com/nVdEe

I would be pleased to hear from other people who dissasembled their T42.
If they can remember visible differences.

Also, are there opinions about POST diagnostic cards. Are there some efficient ones for the T4x?

Lastly, does someone have an idea about the price of a correct reflow equipement and supplies? I can imagine some equipments being very expensive, but what about one to unsolder/resolder main chips like the GPU?
I see this as a long-term investment.

A proper re-balling station is in the $20K range.

A replacement motherboard is $100 or less.

Your money, your call.

Go read www.reflowrepairs.com and the links you find there.
Send your mobo there for a repair, it's the only reliable company that I know of.