I've seen this issue show up in a couple of other places, but with no real explanation. I thought I'd try to tackle it once and for all here.


Bought a G73SW and the DC input began sparking on occasion. Finally the mainboard shorted out.

I replaced the mainboard but now the display did not work. But the VGA output worked. And I used the external display to run several diagnostic tests on the hardware and it did not find any issues.


I ordered a new screen ... still no joy. This rules out the screen. I have two different power adapters. This rules out the power adapter. New LVDS cables made no difference.

In both cases I tried all known methods to get a display. Resetting BIOS, resetting PMU, new CMOS battery, toggling display FN-F6/F7. I even assembled the entire thing, screws and everything to see if somehow the display doesn't work unless it's fully assembled (which is the case for a few random laptop models).


The only thing I did not replace was the video board. But this passes all tests and boots fine with no errors.


That leaves the mainboard.


Could the replacement motherboard I ordered have a faulty output to the screen, but otherwise work perfectly fine?


Is there a more detailed drill-down or diagnostic you can do on the mainboard?
I want to be sure before I send this one back.


Is there some trick to mainboard replacement (specifically for this model) to get the display working?


(It's not under warranty or I would have RMA'ed.)


Edit:

I compared the two mainboards and they are identical except that the LVDS port is in the 2nd of two possible slots on the circuit board. There are a few other differences, but this explains why the board is not powering the display. The BIOS probably has it powering the empty port.

Both boards are G73SW.

I'll have to wait for a new battery to try flashing the BIOS, and maybe need to find a custom BIOS of some kind from Asus.

Annoying.