HP G61 Screen goes black

[davg]

I have an HP g61 laptop here and the video display goes black. The video card is working because it is fine on an external monitor. I have replaced the inverter and still the same. It appears like a loose connection but I have checked and re checked but can't find one. The only connection I didn't check was the the ones on the lamps (ccfl)? I did not pull the lamps. Has anyone seen this problem before and any suggestions?

[gabik111]

Re: HP G61 Screen goes black

Well , do you see anything on the screen when you lighting up by a flashlight? If you see something then there is a backlight problem , but if there's nothing you might search on the mobo and you have to look closer to GPU.

[davg]

Re: HP G61 Screen goes black

Well , do you see anything on the screen when you lighting up by a flashlight? If you see something then there is a backlight problem , but if there's nothing you might search on the mobo and you have to look closer to GPU.

Thanks gabik111. No there is no image that I can see when I light up with a flashlight. What to look for on the mobo? Could a driver cause this condition within the GPU?

[gabik111]

Re: HP G61 Screen goes black

Depends on what conditions were during laptop using (high temperatures , extreme pressure on the housing) I can say that are GPU balls. Try to push the GPU or heat it up (not overheat) during startup. Propably you will get something on LCD. Also find lid switch and check it out. This is not backlight issue (no image on screen).
I can say for 99% this is GPU for reballing or exchange (you got ATI graphic so I don't think you need to replace it) IMHO.

[davg]

Re: HP G61 Screen goes black

Depends on what conditions were during laptop using (high temperatures , extreme pressure on the housing) I can say that are GPU balls. Try to push the GPU or heat it up (not overheat) during startup. Propably you will get something on LCD. Also find lid switch and check it out. This is not backlight issue (no image on screen).
I can say for 99% this is GPU for reballing or exchange (you got ATI graphic so I don't think you need to replace it) IMHO.

Thanks again gabik111 I am not sure how to respond to this post as I am not sure what reballing is or how it is done? In my search I found that it is the process of re soldering on the chip? Is this a common problem? Sounds complex? I will look for the lid switch and hope it is the problem?

[gabik111]

Re: HP G61 Screen goes black

Yes , reballing is replacing solder balls under BGA chip. Special tools are required to do this. Some peoples trying to repair damaged balls using heat gun or hot air soldering station but this partially helps. Proper repair contains chip removal , cleaning pads , install new balls on chip and solder to mobo (best way to use infra-red station).
Maybe this switch will solve problem .

[davg]

Re: HP G61 Screen goes black

Yes , reballing is replacing solder balls under BGA chip. Special tools are required to do this. Some peoples trying to repair damaged balls using heat gun or hot air soldering station but this partially helps. Proper repair contains chip removal , cleaning pads , install new balls on chip and solder to mobo (best way to use infra-red station).
Maybe this switch will solve problem .

Ya to complex for me Thanks gabik111. Question; when I open and close the lid the puter sleeps and awakes which would be an indication it is working if this is the switch you refer to? By changing the function of the switch in the power setup would this eliminate the switch? If I disassemble the thing the video comes back but after re-assemble it's gone again I was suspecting a bad connection on the ribbon cable to the monitor? but than that being the case the screen would light up bright? I don't know if I am making any sense here?

[gabik111]

Re: HP G61 Screen goes black

It can be bad ribbon cable. But also when you asseble everything motherboard can deformate and it can cause bad connection (or solder point) on mobo. Remove mobo and connect everything to get it works. I had similar problem in vaio laptop. I found that add small washer in one point put life to the laptop.
But if this is a ribbon cable it will be easy to fix.

[davg]

Re: HP G61 Screen goes black

It can be bad ribbon cable. But also when you asseble everything motherboard can deformate and it can cause bad connection (or solder point) on mobo. Remove mobo and connect everything to get it works. I had similar problem in vaio laptop. I found that add small washer in one point put life to the laptop.
But if this is a ribbon cable it will be easy to fix.

Thanks again gabik111 I have to do more investigation. Having an intermittent problem makes the task more difficult.

[skywalker]

Re: HP G61 Screen goes black

You do not need to reflow / reball the gpu as the unit displays on an external
monitor

[davg]

Re: HP G61 Screen goes black

You do not need to reflow / reball the gpu as the unit displays on an external
monitor

Thanks skywalker you have obviously read the post above, any suggestions? As I indicated above I have had the thing apart several times and each time I get video. I have re-assembled the thing and still had video but for reasons beyond me it goes black and the only way to get it back is to take it apart again?
At first if the lid was held in a certain position it was fine but if the lid was moved it went black, move it back it was ok again. I guess it could still be a broken cable? And I don't have one to try?

[gabik111]

Re: HP G61 Screen goes black

If you got multimeter you can remove ribbon cable and try to measure it - every line.
And back to skywalker post - this is not obvious. LCD is using diferrent driver than external monitor and sometimes when external monitor is working - LCD is not, and then you have to find what is going on...

[mattbrad2]

Re: HP G61 Screen goes black

skywalker is correct. The GPU, if the problem, wouldn't properly POST so you wouldn't get a video signal on the LCD or external. The LCD itself is bad. I had one in my shop just the other day that I had to replace the screen.

[gabik111]

Re: HP G61 Screen goes black

skywalker is correct. The GPU, if the problem, wouldn't properly POST so you wouldn't get a video signal on the LCD or external. The LCD itself is bad. I had one in my shop just the other day that I had to replace the screen.

But LCD itself got two circuits. Backlight and LCD integrated drivers (that driving vertically and horizontally all pixels) so in this case both died in one second...

[cleonis]

Re: HP G61 Screen goes black

i have a hp g61 in which screen went black after some time so i replaced the inverter but there was still a problem so i decided to change the cable that also didnt work after going through the forums i thought it was a gpu issue so i changed the mobo still the result is same the only change is now when the screen goes black qand if i close the lid and open it back i get display for few seconds it is confirm that problem is with screen but not sure whether it is back light or the screen itself