CQ56 White screen

[732914TECH]

Hoping someone could chime in for me. I had a customer bring in a Compaq CQ56 laptop that had a white screen on the screen when turned on, told the customer it was most likely the screen, so I tested it with an led lcd screen and it worked, told them it was done and they picked it up, saw that it worked and went on their way. The next day they said it went white again and had them bring it back and replaced the screen again thinking maybe it was just a bad screen. NOw a few days later they said it lasted a few more days but happened again. At this point Im hoping its the cable is bad. I really hope its not a GPU issue. Can anyone confirm its just a cable or do i need to order a cable and hope for the best?

 

[14049752]

Can anyone confirm its just a cable

You really didn't give us a whole lot to go on...and honestly all you'd get on this type of issue are guesses. A cable could be one cause. You're the only one in any position to confirm if it's the problem or not.

 

[smashedbotatos]

It could be GPU, Cable, or inverter going haywire. If you replaced the LCD that means it is less likely to be the bulb.

I would try and recreate the issue first hand. Run video memory stress test like the one on Hirens. See if heating it up causes the issue, if so i'd say GPU.

Try a new cable if you have one.

Inverter is a toughy.......you may just have to replace it and see what happens.

Granted fixing it is going to net you the best sale, but usually when I see problems like this on a laptop similar to this I just tell folks that it may be a number of things, and they would be better off with a new laptop.

From me experience people don't like to spend a lot of money or time on fixing a laptop.

 

[14049752]

It would not be the inverter.

 

[mein]

It's very unlikely to be an inverter issue if you are using an led screen. The lower voltages required by LEDs means that very few of such screens have LEDs

 

[732914TECH]

Correct it would not be an inverter since its an LED backlit screen, What I was looking for is if anyone has had the same issue with the same laptop. Pretty much its just trial and error but I wanted to hear if anyone has encountered the same problem. And right now the screen is white So i cant really test the GPU.

 

[phaZed]

I have had the white screen under 3 different scenarios.

1. The GPU is going. You can generally test this by hooking up an external monitor. If it work, then it is unlikely to be a GPU issue.

2. Bad screen or connector not seated properly. Since you have replaced the screen a few times.. I would think it's safe to assume this isn't the issue.

3. Bad LCD cable. Always goes bad on this model.. right where the cable passes by the hinge. Usually you can turn the laptop on while disassembled and squeeze/deform the cable to get VGA/white screen... if so.. 100% cable issue.


Beating that dead horse... why would anyone suggest a bad inverter if the screen is white? I'm not picking on you guys, but c'mon. The only way the screen would show up white is if the inverter and bulb are WORKING correctly... otherwise it would be a black screen. On another note.. I have replaced ONE, count it.. ONE inverter out of say 300-400 screen issues. Inverters RARELY go bad, contrary to popular belief.

 

[smashedbotatos]

I
Beating that dead horse... why would anyone suggest a bad inverter if the screen is white? I'm not picking on you guys, but c'mon. The only way the screen would show up white is if the inverter and bulb are WORKING correctly... otherwise it would be a black screen. On another note.. I have replaced ONE, count it.. ONE inverter out of say 300-400 screen issues. Inverters RARELY go bad, contrary to popular belief.

I have seen a case where the inverter was causing this specific issue, but not with an LED screen.

I have seen an inverter working, but incorrectly and thus causing the screen to be a bright white. (From what everyone else is saying, I misdiagnosed this, but regardless it worked properly when it left the shop.)

Otherwise I don't run in to many issues with inverters, I have replaced maybe 3 in the past 6 years, and that was one of the cases I had.

 

[14049752]

I have seen an inverter working, but incorrectly and thus causing the screen to be a bright white.

There's no way that case was just the inverter. The inverter's only function is to light the backlight. If there is no image on the screen, the inverter (while working) would be illuminating a black screen. If it was bright white, then there would have to be signal (good or bad) to make the screen white.

 

[14049752]

What I was looking for is if anyone has had the same issue with the same laptop. Pretty much its just trial and error but I wanted to hear if anyone has encountered the same problem.

My point was that it's equally likely to be a couple different things. Nobody can confirm for you that it's the cable, just like nobody can confirm for you that it's not. It doesn't matter what caused the issue in another case, because it may not be causing the issue in your case. As the post above somewhere said, it can be a few different things... If I have to order parts to test, I start with the most likely part or least expensive but equally likely part. In your case, that'd probably be the video cable.

On another note.. I have replaced ONE, count it.. ONE inverter out of say 300-400 screen issues. Inverters RARELY go bad, contrary to popular belief.

That's extremely contrary to my experience. I replaced two dead inverters just today. If you've only replaced one out of 300-400, you're very much in the minority and I'm willing to bet most others would back me up on that.

 

[732914TECH]

I have had the white screen under 3 different scenarios.

1. The GPU is going. You can generally test this by hooking up an external monitor. If it work, then it is unlikely to be a GPU issue.

2. Bad screen or connector not seated properly. Since you have replaced the screen a few times.. I would think it's safe to assume this isn't the issue.

3. Bad LCD cable. Always goes bad on this model.. right where the cable passes by the hinge. Usually you can turn the laptop on while disassembled and squeeze/deform the cable to get VGA/white screen... if so.. 100% cable issue.


Beating that dead horse... why would anyone suggest a bad inverter if the screen is white? I'm not picking on you guys, but c'mon. The only way the screen would show up white is if the inverter and bulb are WORKING correctly... otherwise it would be a black screen. On another note.. I have replaced ONE, count it.. ONE inverter out of say 300-400 screen issues. Inverters RARELY go bad, contrary to popular belief.

thank you for your input, this is what i was looking for, i forgot to mention the laptop works perfectly with an external monitor hooked up using vga, but i figured the GPU should be working, I have had issues with similar HP models and the cables as well. I Just hope this is one of them lol

 

[PC-MOT]

Its a long shot but a few months ago I had a screen stay white after I bent a pin in the monitor cable plug on the board, weird thing was the pin bent so far that the plug appeared to be seated perfectly, a strong torch and a tiny screwdriver managed to bend it back, fired up, and all fine.

 

[732914TECH]

yea ive had that happen when i was installing the screen, but this has been happening a few days after the customer recieved their laptop back

 

[billyboy]

We had a compaq in last week with the same issue, white screen. We tested the screen and the cable and decided it must be the gpu. We sent it off for motherboard repair and they fixed it saying they replaced a power ic!

Although we never got it to boot into Windows with a new screen like you did so maybe the problems are unrelated.

 

[732914TECH]

Update: I replaced the cable and the newest screen started to work again. Ill report back with any changes.