Laptop screen issues

[bogan]

My laptop screen started having issues last night, and appear to go into a test pattern, with solid green/blue/red followed by black/white and some gradients in between. While it is doing this the VGA output is fine, and the compute boots and shuts down as normal. Unfortunately I changed some settings awhile ago to get desktop 'span' going, so I can't get anything up on the vga output/screen. I took it all to bits last night, but couldn't see any connector problems.
My thinking is, VGA is working so the display board might still be good, screen test pattern is working, so screen might still be good.
Laptop is a G51VX (bestbuy).
During startup and shutdown the screen will flicker to what it is supposed to display, though this image is often interlaced with black lines, or only fills the top half.

So whatcha reckon? Screen? Cable? Display Board?

[SMOKEU]

Put FreeBSD on it.

Does the screen flicker when you're in the BIOS, or only within the OS?

[Buyasta]

Definitely sounds like the issue is the connection between motherboard and LCD. If the connectors look fine at both ends, it could be the cable itself, although I assume it's an FFC with ZIF connectors at each end, and I've always found it tricky to tell if ZIF connectors are damaged or not.

[bogan]

Does the screen flicker when you're in the BIOS, or only within the OS?

both


Definitely sounds like the issue is the connection between motherboard and LCD. If the connectors look fine at both ends, it could be the cable itself, although I assume it's an FFC with ZIF connectors at each end, and I've always found it tricky to tell if ZIF connectors are damaged or not.

Not a FFC cable, and only the screen end has a ZIF, the other is a 2x10 header, I will take the wrapping off the cable and see if I can see anything wrong.

Are screen comms two way? Like is the computer detecting the issue and putting the screen into test mode? or is the screen controller detecting a bad signal through the cable and putting itself into test mode?

[Buyasta]

Not a FFC cable, and only the screen end has a ZIF, the other is a 2x10 header, I will take the wrapping off the cable and see if I can see anything wrong.

Are screen comms two way? Like is the computer detecting the issue and putting the screen into test mode? or is the screen controller detecting a bad signal through the cable and putting itself into test mode?

I don't know for certain, but I'm pretty sure it'll be the latter. If you can find a replacement cable on trademe or elsewhere, I'd grab that and give that a go.

What's the issue you're having with getting your external monitor to work properly?.. Is it just the fact that the laptops LCD is the primary display and everything is opening on that instead of the external display?.. If so, you should be able to toggle between both being active and either one active with the other disabled using the display function key on your laptop, or if you're running Win7, Winkey+P.

[bogan]

Jiggered the flat ribbon cable on the back of the panel, and it seems to work again, can't seem to find replacement connectors, so will just put some tape on this one, and hope it lasts a while longer! Apparently there is a 1080p screen upgrade avaialable, so I might do that (and get one that comes with a new connector) if it goes totally bung.


I don't know for certain, but I'm pretty sure it'll be the latter. If you can find a replacement cable on trademe or elsewhere, I'd grab that and give that a go.

What's the issue you're having with getting your external monitor to work properly?.. Is it just the fact that the laptops LCD is the primary display and everything is opening on that instead of the external display?.. If so, you should be able to toggle between both being active and either one active with the other disabled using the display function key on your laptop, or if you're running Win7, Winkey+P.

Yeh, cos I changed it under the Nvidia control panel, the hotkeys don't work.

[bogan]

back together, is working, and only 4 weight reduction screws still on the table :D

[Akzle]

My laptop screen started having issues last night, and appear to go into a test pattern, with solid green/blue/red followed by black/white and some gradients in between. While it is doing this the VGA output is fine, and the compute boots and shuts down as normal. Unfortunately I changed some settings awhile ago to get desktop 'span' going, so I can't get anything up on the vga output/screen. I took it all to bits last night, but couldn't see any connector problems.
My thinking is, VGA is working so the display board might still be good, screen test pattern is working, so screen might still be good.
Laptop is a G51VX (bestbuy).
During startup and shutdown the screen will flicker to what it is supposed to display, though this image is often interlaced with black lines, or only fills the top half.

So whatcha reckon? Screen? Cable? Display Board? i was suspecting hardware initially - folding screens up and down always ends up wearing through something. the connections are very small.
best bet would be to find an identical replacement screen and try plugging it into the board.

for a minute i thought you mighta broke something in the OS. and maybe it is. you're unclear.

your laptop keyboard should have a soft button key that looks like a monitor/screen, or maybe two. (just like pushing ctrl +c to copy stuff, push your "function" button, whatever it's called, and the key with the monitor icon on it) do this once the lappy has booted and check for VGA output/ your laptop screen. push it several times about 15-20 seconds apart as it will often cycle between outputs rather than autodetecting where it should be.

if no joy, go and buy a laptop that isn't shit.

[bogan]

Ok, its shat itself again, and is coming and going intermittently, with no apparent correlation to cable jiggling. I managed to get the VGA port back under hotkey control while the screen was working though, so this is handy. Kind of looks like the circuitry on the panel is a bit fucked. Will look into updating the drivers and any bios updates, just in case.

[steve_t]

Reading online about the model having GPUs mounted with thermal pads and being poorly mounted. Could it be overheating? Some people have removed the thermal pad and remounted the GPU with some eg arctic silver. Maybe worth a shot?

[Buyasta]

Reading online about the model having GPUs mounted with thermal pads and being poorly mounted. Could it be overheating? Some people have removed the thermal pad and remounted the GPU with some eg arctic silver. Maybe worth a shot?

The chances of the external VGA continuing to work if the issue was with the VGA are pretty slim. Also when the issue is with the GPU you'd be more likely to see the graphics somewhat working, but with corruption, artifacting and random rebooting - the fact it was reverting to a test pattern makes it seem more like no signal being received whatsoever.

[bogan]

The chances of the external VGA continuing to work if the issue was with the VGA are pretty slim. Also when the issue is with the GPU you'd be more likely to see the graphics somewhat working, but with corruption, artifacting and random rebooting - the fact it was reverting to a test pattern makes it seem more like no signal being received whatsoever.

Those were my thoughts, I guess with it not looking like a cable issue (and no other cables available), I have to figure out if it is the screen electronics, or the VGA ones, and I guess there isn't much between the VGA out, and main screen out, they both come straight from the graphics chip right? Found a screen for about $120, so will order that 2moro unless somebody has a revelation...

[Buyasta]

Those were my thoughts, I guess with it not looking like a cable issue (and no other cables available), I have to figure out if it is the screen electronics, or the VGA ones, and I guess there isn't much between the VGA out, and main screen out, they both come straight from the graphics chip right? Found a screen for about $120, so will order that 2moro unless somebody has a revelation...

Yup, I'm pretty sure that's the case, so if the problem doesn't appear to be the cable, the panel looks like probably the best bet.

[Akzle]

Yup, I'm pretty sure that's the case, so if the problem doesn't appear to be the cable, the panel looks like probably the best bet.
LCD panels do not use VGA signal. it's different and proprietary. (and a pain in the a55)

[bogan]

LCD panels do not use VGA signal. it's different and proprietary. (and a pain in the a55)

But if it is the same chip supplying the (still working) VGA as well as the panel signals, it suggests one of the chips on the panel is damaged, and not a graphics card problem.

[Buyasta]

LCD panels do not use VGA signal. it's different and proprietary. (and a pain in the a55)


But if it is the same chip supplying the (still working) VGA as well as the panel signals, it suggests one of the chips on the panel is damaged, and not a graphics card problem.

Yup, exactly - there's not going to be any additional circuitry for the LCD output like there will for the VGA, to convert from a digital signal to an analogue one. So if it were the VGA out that wasn't working, then it could be an issue with the graphics hardware, but since it's the LCD that's the issue, that seems pretty unlikely.

[ducatilover]

Something's broken mate

You're welcome.

[5150]

My laptop screen started having issues last night, and appear to go into a test pattern, with solid green/blue/red followed by black/white and some gradients in between. While it is doing this the VGA output is fine, and the compute boots and shuts down as normal. Unfortunately I changed some settings awhile ago to get desktop 'span' going, so I can't get anything up on the vga output/screen. I took it all to bits last night, but couldn't see any connector problems.
My thinking is, VGA is working so the display board might still be good, screen test pattern is working, so screen might still be good.
Laptop is a G51VX (bestbuy).
During startup and shutdown the screen will flicker to what it is supposed to display, though this image is often interlaced with black lines, or only fills the top half.

So whatcha reckon? Screen? Cable? Display Board?

Oh FFS, stop looking at all that porn :shifty:

[bogan]

Kept using it cos I'm pretty cheap, and wanted to be sure of the problem. I also noticed it would drain the battery even when turned off, so I thought maybe something else was wrong, but I disconnected the panel and it stopped draining the battery too, so another point in favour of a new panel.
Seems a bit strange that a bung panel could drain the battery though, figured it would have all been turned off 'upstream'.

[ducatilover]

See, I told you something was broken.

[Buyasta]

Kept using it cos I'm pretty cheap, and wanted to be sure of the problem. I also noticed it would drain the battery even when turned off, so I thought maybe something else was wrong, but I disconnected the panel and it stopped draining the battery too, so another point in favour of a new panel.
Seems a bit strange that a bung panel could drain the battery though, figured it would have all been turned off 'upstream'.

That is quite stupid, you'd think the laptop would cut power to the screen when it's turned off.

[bogan]

Irritating problem still persists. Got a new panel, have not had any of the block color 'test patterns', but the LED backlight often goes out, or the screen goes completely (thought this may just be lack of backlight not allowing me to see the pixels). Anyway, when I unplug and plug back in the cable connecting to the panel, it often comes right, and is fine to close/open lid or move it around while it is going. however, when I turn the computer off, and on again, it often doesn't fire the panel up. So I'm thinking it is more than a connection issue, maybe the panel power is left on, and causes the driver chips on the panel to go into a sleep mode, since there is already power turning the computer on doesn't wake it up, but un-plugging the cable does. Anybody else got any theories?

[bogan]

Ok, just did a restarts, screen worked but no backlight. Unplugged and re-plugged the other end of the connector and it came right again. Something fishy with the LED backlight controller perhaps. Will try it a few more times during the course of normal useage, and maybe just put in a little button to reset the backlight as needed.

[pete376403]

LED backlights or cold cathode flourescent? If CCF - could be a problem with the inverter. Does the screen have a small (about 100mm long x 10-15mm wide) board, usually found at the bottom of the display.
Inverter supplies the high voltage for the CCF to illuminate.
http://www.laptopscreen.com/English/section/FAQ/1245191276/Correct+backlight+type+for+your+new+screen/

[bogan]

LEDs, though I'm fairly sure these run an inverter too, but only a 20V or so one.

[bogan]

Narrowed a fix down to reseting the enable pin for the panel LEDs; the inverter is on the RHS screen plug so no too hard to get access to. Interestingly, the first panel had no problems with the backlight; so as far a fault diagnosis goes :confused: But as far as kludging it to a workable state goes :D Just put a microswitch on that signal wire, and give it a tap every time the laptop has finished booting, or the panel needs a wakeup. Few days in, and no problems so far...