Need help ASAP... No backlight issue.. STRANGE!

Lej

Honorable
Jul 24, 2012
9
0
10,510
This is ridiculous.. I've got an Asus U56E that I was replacing the screen in. The screen was cracked, but the backlight still lit up. So, I order a new screen, put it in, and its fixed!.... a few moments later, the screen just goes dark!.. The backlight had cut out.. So I plug in an external monitor via VGA, and it comes up on the monitor and everything is fine.. So I go to inspect what could of just possibly happened. I notice a blown fuse close to the spot where the screen connects to the motherboard, and I also notice a small hole in the tape wrapped around the screen connector cord which looks like it had a torn wire. So I order a new board, and new screen cable (and at this point, there's nothing else to replace? right?) and the problem is still there!... No back light!.. What could it BE!??!?! Iv'e tested BOTH screens in another Asus machine and they work PERFECTLY! .. no problems!.. But if I test them back in the original Asus, I get NOTHING!... How is this possible?!?! I've checked the fuse on the new board, and it's fine!.. This honestly makes no sense... It's almost like something needs to be configured in the Bios somewhere, but there's nothing remotely close besides flashing it... How could this be?!?
 

Lej

Honorable
Jul 24, 2012
9
0
10,510
Yes, but the thing is, the old screen doesn't even lit up like it use to. (It does in a different laptop.. It lights up fine with all the cracks showing..) It's so weird!!
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560
I am... very confused. I imagine this is rather frustrating.

Hm.

So it must be something in the laptop. If the new screen works in other systems and no screen works on the laptop, it can't be anything else. So, what could it be... Did you double-check all the connections? Make sure all the cables are plugged in correctly? Hm....

I don't want to suggest calling ASUS, because I know how useless tech support can be, but I am stumped. It seems like you've covered all the options.
 

Lej

Honorable
Jul 24, 2012
9
0
10,510
Trust me, this is extremely frustrating. I've worked in a computer repair shop for years, and I've never had something so annoying, and possibly costing us so much)..

I tried calling Asus, the foreign girl said the "bulb" was burnt out.. I had to explain to her that this was a LED LCD, and that it worked fine in another machine.. She was CLUELESS...

I've checked all the connections, and all that.. Tested the magnet on the lid, and it works.. (the screen is dim but I can see it cut off when I shut the lid)..

I've had a fuse blown before, but the fuse is fine on the new board.. So I just don't even know. I never work on the machine with the battery or cord in. I always press the power button a few times as well to make sure it's drained before touching anything.
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560
I feel your pain. I hit a few walls building this rig. Not being able to work out a problem drives me up the wall.

Hm. Insofar as I know, the BIOS won't be any help to you. But, if you aren't silly, flashing it is quite simple. You could try it. At least cross it off the list.
 

Lej

Honorable
Jul 24, 2012
9
0
10,510
I think that's an option. That's really the ONLY thing I haven't tried... My co workers say it's "risky" and could mess up the laptop.. but I use to do it all the time... I mean there's a tutorial with pictures for the exact model on Asus's website. But how often does flashing the bio's fix a backlight issue....
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560
Flashing the BIOS is easy and risk free -- if done right. But yeah, if you don't do exactly what it says, you can render the laptop as useful as a brick.

I don't think it'll work, but like you say, what else is there? Very shitty problem :/
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560

That's... something I did not think of. Would explain a lot, actually.

You might be on to something.
 

Lej

Honorable
Jul 24, 2012
9
0
10,510
I'll have to test it when I wake up, It's 6 in the morning here. How often does a missing screw cause a BACKLIGHT to not work though?.. I mean honestly, there's nothing else to replace. The board, cable, and screen have all been replaced..
 

Lej

Honorable
Jul 24, 2012
9
0
10,510
Well, I'm looking at it now, and I just don't see how a screw completes any circuit anywhere... I'm almost out of options... I just don't get it.
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560
I am at a complete loss.

The only thing I can possibly think of, is taking the entire thing apart and putting it back together slowly. Sometimes you can find something you missed or did wrong or was damaged.

I've got nothing else :/
 

MatildaPersson

Honorable
Jan 12, 2013
22
0
10,560

I guess. Odds are pretty slim, but you know - when you've eliminated all the obvious answers, whatever remains, however unlikely, must the the solution.
 

Tom Yun

Honorable
Apr 18, 2013
1
0
10,510
I had the same problem replacing a screen on an ASUS U35jc. Turns out the backlight fuse was blown on the motherboard. It was easy to tell because it was completely charred. Probably happened because I didn't disconnect the battery and/or power cord when I hooked up the replacement screen. Anyway I tested this by bridging the blown fuse with a screwdriver and the screen backlight worked. I eventually just soldered the fuse and it's worked ever since. Don't have pictures but the backlight fuse was located right above (north of) the LED display connection on the motherboard. There were actually two fuses in parallel at this location. The blown fuse was located above (north of) the working fuse so that must be the backlight fuse. BTW those fuses were tiny. I don't know the configuration of motherboards for other sizes but I'm pretty sure this applies to any 13.3 inch ASUS U series machine.
 

Expert Computer

Estimable
Sep 9, 2015
1
0
4,510
Did you ever get this issue resolved and if so how did you get this fixed? I am experiencing the same issue.