ASUS S400CA-DH51T laptop screen intermittently scrambles and enters hung state

Whenever I'm using my ASUS S400CA-DH51T laptop, the screen will intermittently scramble showing patterns with all RGB colors. The fans will kick in at 100% at this point (?). The laptop does not respond to network ping at this point. Once the display scrambles, I haven't been able to get it out of this state even with key presses/mouse movements. It seems to be correlated with moving the laptop certain ways (loose hardware connection?).

Things I've tried:
Windows Update
ASUS Driver Update
Looking at temps in HWMonitor/SpeedFan (they're okay)
Opened up and cleaned with canned air
Looking for shorts
Reseating ribbon cables
Disabled Intel Display Power Saving Technology (DPST)
Looked in Event Viewer (nothing relevant)

I sent it in for RMA warranty repair, and all they did was wipe the hard drive. The display scrambling still happens, as nothing was fixed. I'm a software engineer, and this problem has to be one of the most frustrating I've encountered, especially since it is very hard to repro and test that it has been fixed. I haven't even been able to diagnose it yet. Any ideas?

 

Does anyone have a service manual for the ASUS S400CA-DH51T? I'm pretty sure it's moving the hinge on the display that is causing the problem. The ribbon cable connection on the OTHER end (to the LCD/controller, not the motherboard) might be the culprit, but I want to be careful how I disassemble the LCD. This doesn't fully rule out the motherboard side though. Thin wires that are precariously soldered to the motherboard connect to the display through a sleeved wire that snakes through a conduit through the hinge. There could be a bad solder joint or a small tear somewhere in one of the wires.

Ideally, I would like ASUS customer service to replace my laptop (while it is under its one-year warranty). What can I use as a bargaining chip to get them to do so? It irks me that their idea of repairing this was only wiping the drive and sending the same machine back.

 

Bump, I really need help getting this laptop to work again.

 

If the system is still under warranty, then it's highly recommended that you contact ASUS to get it repaired instead of DIY.
They may charge you instead if they find the system is damaged because of mishandling.
Additionally, you will need some parts from ASUS in order to replace the defective items.

 

Right, but when I sent the laptop into ASUS RMA for repair the first time, the only thing they did was wipe the OS. Is there a way to get them to escalate the request?

 

You can call them up and request to speak to a supervisor, explain the situation to the supervisor and hopefully they will pick up the ball on this.

 

Hello TheChuckster,

Now I am a similar situation with my ASUS S400CA...

Could you find a service manual? How did you fix your computer...

Thank you very much!

Kind Regards...

 

I took it to a local electronics shop who had service manual access with ASUS. Turns out the screws used to connect the motherboard to the chassis were shorting because they weren't the right length.

 

Thank you very much for your fast answer.

So at the end it was nothing to do with the screen!!
I also thought it was a problem with the LCD cable....
Could you please specify which screws are exactly?

I am going crazy with this matter... I cannot disassemble the screen either found the service manual! have you found it?.

Regards,
Miguel