The story of how I ruined my G751JT

[Icemixxy]

Hi everyone,

I thought I'd share my story, in case someone was thinking of doing something similar or just for the info it can provide, if there will be any,
I've had my G751JT for 1,5 years now and since the company handling the warranty service in my country is unreliable, I wasn't send it to them anyway.
I thought it was time for a nice cleaning, so I took the whole thing apart, applied some diamond thermal paste and connected a band of smd leds to the vents, just like in the "xotic pc afterburner fx"
I wore anti-static gloves, disconnected the battery at the first chance I had, proceeded with caution every step of the way.
Somehow, something, went very wrong.

Right now, the laptop turns on, boots into windows, but the screen is empty. During bootup, the screen is blank, but when Windows loads, the backlight is there, but the screen is black, as if I'm looking at a black picture in full screen. Also, I can use the laptop without problems on an external monitor.
Weird thing was, after I put it back together, before I soldered the leds onto the vents, I turned it on and it was still working.
For the love of me, I can't figure out what it is, so I took it to a repair shop in my city, at a first glance they said reballing the gpu. I doubt it, but I don't have a better idea.
Anyone experienced something similar?
PS: tried the remove battery, keep power pressed for x seconds/minutes after the screen issue. Didn't work.
I will try to keep you guys posted as much as I can with the outcome.

I have been dabbling with PCs for the past 15 years, took apart a few laptops aswell for cleaning, but this is the second one that died on the table. With the first, at the repair shop they said it wasn't my fault, just coincidence that the battery got shorted when I turned it on after cleaning.
I'm either too clumsy or have a tremendous amount of bad luck.

Hoping for some ideas of what could this be or calming words!:)

[warryabel]

possible that you have connect vga cabel not exact...?

[clockworksatan]

If it works fine when you've got an external monitor connected, I'd imagine that your soldering work must be good - but would definitely go back over all of the connectors to the screen and make sure that everything connected properly. It could be something reeeeally simple!

[Icemixxy]

I found someone having something similar, this part shows exactly what I'm seeing after windows loads: https://youtu.be/an9v9p5_ydE?t=4m11s
Nothing until then, not even the rog logo lights up until windows loads

[Icemixxy]

The cable is fine. The guys at the repair shop suspect a reballing, which I don't think is the case. If the screen wouldn't be working at all, I could accept reballing to be the issue, but the screen lights up when windows loads, but no image. Also, after reconnecting the cooling pipes and inserting the motherboard, right before I started with the fans, the screen was still working, so I doubt it's reballing. I'm just afraid that reballing would make everything worse. Right now I could use the laptop with an external screen.

[Googlegot]

Icemixxy wrote:
The cable is fine. The guys at the repair shop suspect a reballing, which I don't think is the case. If the screen wouldn't be working at all, I could accept reballing to be the issue, but the screen lights up when windows loads, but no image. Also, after reconnecting the cooling pipes and inserting the motherboard, right before I started with the fans, the screen was still working, so I doubt it's reballing. I'm just afraid that reballing would make everything worse. Right now I could use the laptop with an external screen.

This really seems like an OS issue to me. I would suggest booting into a linux live cd/usb drive and see if you get video with the internal display. It doesn't make sense for it to work before the OS loads, but stop afterwards, unless there is a driver issue.

If you don't get video to the internal display after booting to a linux live cd/usb, try reseating your LVDS connector (the one that connects the display to the motherboard, wide and flat with a plastic pull tab). Also try updating your BIOS.

[Icemixxy]

Googlegot wrote:
This really seems like an OS issue to me. I would suggest booting into a linux live cd/usb drive and see if you get video with the internal display. It doesn't make sense for it to work before the OS loads, but stop afterwards, unless there is a driver issue.

If you don't get video to the internal display after booting to a linux live cd/usb, try reseating your LVDS connector (the one that connects the display to the motherboard, wide and flat with a plastic pull tab). Also try updating your BIOS.

It does not work before OS loads. Everything working fine on external, bios, windows loading, and windows, but the laptop's screen isn't working at all and doesn't even light up until after windows loads.

Right now, I'm just concerned if reballing the gpu would make things worse and if I should take it somewhere else. I've read different opinions on reballing

[Clintlgm]

Yes I agree if your notebook runs a monitor separate from your notebook, without issues, the issue is with your screen or connection of screen to Motherboard, if the connectors are good on both end have a good look at the cable where it transitions from bottom case to Lid.

[Dreamonic]

Where did you make your solder connection is what we need to know. You made mention of using the ROG backlit logo at one point on the back of the screen (posted somewhere else). Perhaps where you connected your LEDs dropped the voltage just enough from what was required to operate the gate for PWR to another connection on the board that handles your internal display output. Only you would know this as you did the mod. So you may need to cut your LEDs power and see if it allows the screen to work as it did before.

Also I believe the G751's use a 30-pin eDP display cable (IPS panel) for connection and not the LVDS cable like the older G-series used (TN panel). That's besides the point anyway but worth a mention. Most results for screen replacements on various sites for the G751's make mention of 30-pin eDP.

Highly doubt the GPU has hairline cracked solder joints all of a sudden after such a mod when everything was fine before it. I've seen a similar issue back in the day with the HP DV9000 Series where the oven method worked for it but your issue happened right after your mod, not from high and low temperature cycling to need a reflow. I'd back track your LED connection to the board (or whatever you used) and revert what you did and see if it corrects the screen issue is where I'd start.

[Icemixxy]

So a little update and answers:)

I took the laptop out from the local service, and sent it to an ASUS certified one, who, at the first glance, suspected the screen cable. Now I just have to wait for what they find upon further inspection.

@Dreamonic

I soldered the wires from the leds onto the fans. I made a post a while ago yes, because I read somewhere that it would be the best thing to do, to solder the screen logo with the leds, but I didn't want to take the screen apart.
The leds are soldered to their respective fans. I measured with a multimeter to get the wires right, and proceeded. I tried without the fans connected, for max 10 seconds, but nothing happened. Disconnected the battery, kept the power button depressed for 20-30 seconds, connected battery, turned it on again, still nothing, so I reconnected the vents.

Before taking the laptop to the 2nd repair shop, I installed a windows 8, installed just fine, no issues or hanging, but still, only on external monitor. Did not install drivers and such, just wanted to see how the system is keeping it together