G75 internal display issue

Hello guys. I posted this before but can't find it now. So doing it again.

I have an Asus G75vw. I restarted the laptop one day and the internal display stopped working. I reseated the rams and it worked. Next day it didn't display the screen. I could hear the boot sound, windows sound, and external display worked flawlessly. I took it to a local repair shop. (No Asus here) He narrowed it down to the GPU malfunctioning. There is no gpu available so he said to use with external display. I was using the laptop for a few days. Third day I turn it on and the display shows up halfway in the windows login screen on my internal display. It didn't show on boot but it did on windows login. I have been using it for a couple of hours and it's working fine. But I am afraid I will restart it and it will cause problems again.

Stuff I tried:
>Reflashing bios.
>Using another internal screen with another cable.
>Other ram
>No hard disk. No touch pad. No keyboard. No any device connected to motherboard.

I feel it's dust that is causing the issue. I can open up the laptop so any steps you have that can narrow down the problem I am willing to take. Please help me out. I will be really thankful.

G75VW with GTX 660m. If you need more info I can provide that too. Sorry if this is too less of information but I really think it's the gpu malfunctioning or some software issue.

 

Your machine does not have optimus so if you get an external image the GPU is fine, since it's an intermittent problem I would seriously suspect either your internal display cable is damaged or has come loose from the motherboard or display, changing your ram just knocked it back in temporarily or nudged the cable to reconnect a damaged point.

 

Thank you very much for your answer. I feel that too. I tried nudging the cable as much I could but the display coming and going was on it's own will and not the cable. The second thing that really makes me doubt that is that whenever the screen works I can use it as long as I like without it disappearing. It works flawless. I use my laptop on a desk with charger plugged in so physical damage is not much of an issue here. And while I am using it with the screen on and I restart, the screen doesn't show after the restart. Not even in the bios boot screen. So the issue is very weird. And during that restart the laptop has not been moved or handled as it is on the table.

Please provide further pointers for me. I understand that you are a notebook retailer. That makes my hopes just go high. If anyone, it's people like you who can really solve such issues. Thanks again.

Edit: As of now, the screen works after I windows boots and the login screen kicks in. So the issue is a software issue. I cannot see the screen on boot. Something with the bios?

 

Maybe or the LCD panel itself may have a slight issue with the LED power circuitry (which is driven from the motherboard IIRC).

 

I don't know how to check that. Can you guide me?

I noticed another thing. I sent the computer to sleep by pressing the power button. When I resumed it from sleep by pressing the power button again, the screen flashed white for a second and then no display again. I restarted and I got display after the windows login screen not at bios boot. Does that clear up something?

Thank you for the help again. I am sorry about the second thread. I thought it never made through so I reposted.

 

Sounds like a loose connection in the back of LCD, or LVDS cable issue.
You can open it up and verify if you are comfortable with it and see if you can secure it or not.

 

Thanks. I will open up the LCD/lid on Friday. I did open that last time but didn't go all the way to the connector. I will try reconnecting it. I have exams going on so I will do it when I get a gap in between. Thanks for your help guys. Please stay with me on this. I really need my laptop back and you're the only ones who can help me get that.

 

I was just wondering. If the cable is loose or something, why does the screen automatically work sometimes. And it works after windows loading has passed through. Not before that. I never get bios boot on my laptop screen. Sometimes when my external screen is connected the laptop screen just shows up auto after windows loading screen dissapears and windows login screen comes. That's the point the screen works. Not before that. Any explanations for that?

I will do the screen cable check tomorrow.

 

If cable is loose or worn, it can do this when you open/close lid intermittently.

 

Yes thermal exansion/contraction can cause it to work differently at different times in different temperatures.

 

I opened it up today. The cable seems to be the issue. While open I turned on the laptop, the screen worked twice. But then I started packing it. Mid-way I checked. The screen didn't work. I couldn't understand how to get the connector out of the inverter. Can anyone guide me through that? It is a little different for me.

 

Is there any fix for this? I don't think I will find spares for this laptop. This is one of two only in my country I guess. Is the cable the same for all laptops? Or the g74 models? I think the repair guy has a spare g74 lying around.

Edit: I am not sure if this adds to the analysis, but the external display only works when connected before turning on the laptop. Once the laptop is on, the external display won't work. Nor will it work if I send it to sleep and wake it. So the external display only works when you connect it and cold boot the laptop.

 

Call ASUS up and buy the part, but if you cannot confirm the root cause then it's going to be risky.

 

We don't have official support from ASUS in Pakistan. If I need the part, I will need to get it from some other country. Isn't there something I could do to this cable? Or try the cable from g74? Are they the same?

Can someone also tell me how to remove the connection from the back of the lcd? I don't want to damage it. I can't understand how the connector is locked. If someone can explain with pictures that'll be nice. Thanks.

 

Argh, I see.
There are some info about assembly/disassembly here, take a look at it and see if it is what you needed.
Asus G55 ang G75 disassembly / teardown

 

Check out this video also there is this disassembly Manual that may help, The video is very through and comprehensive Ok this video is on replacing a G75 Screen

 

Cables from one machine to the next are not guaranteed to be the same, companies like to change the position of the port and kind.

 

Thanks a lot. Can I rotate the cable and reconnected on the MB to make sure it's tight? I read somewhere and some guy did this to his laptop and it worked. Is it worth a try? I read all those resources but I don't get how to detach the cable from the lcd. I don't understand the lock. Can someone guide me on it? If you have a G75, can you please check? Or should I post a pic?

 

You could use electrical tape (must be non conductive) to help secure the cable.

 

Basically, the LVDS cable simply attaches onto the receptacle on the screen and then secured by a tape. You can make sure on your end that the connection is secured.
The other end of LVDS goes onto the mainboard which is usually no problems, but double check it as well to see if it's really loose or not.

 

I checked the cable. It seems fine. I even reattached it from the motherboard. One more thing I would like to ask is that why doesnt the external monitor work when I put the laptop to sleep and bring it back? Is that normal in such a situation?

I will take the cable to the repair guy so he can open it up and check for damages. There is no spare cable here. So I will have to get it from the US or something. I just want to make sure it's the cable because it will cost me quite a lot.

Thanks for the feedback guys. You're pro in this stuff. Do you guys finalize that it's the cable? I understand mistakes can happen by you too. I won't flame if I order the cable and it doesnt work. But I just wanna know is that something you'll surely say the issue is. 'Cause I only want to order it if it definitely is the issue. No prob if it doesn't work. But your help is all I need.

 

I pulled out the CMOS battery cable to the MB today. I then reconnected it after a while. Whenever I boot the pc now, the date is reset. Is it because the CMOS is not well connected? Or is it weak?

 

If the date is not saving the battery is probably not connected properly.

 

If the cable seems fine but you are not getting display from the external output then double check on the cable because the root case might had been the graphics card module.
The CMOS battery could have been weak therefore not capable of retaining CMOS data, however that shouldn't have any effect to your display issue.

 

Will check that tonight.

{QUOTE=Kevin@GenTechPC]
If the cable seems fine but you are not getting display from the external output then double check on the cable because the root case might had been the graphics card module.
The CMOS battery could have been weak therefore not capable of retaining CMOS data, however that shouldn't have any effect to your display issue.
[/QUOTE]

I am getting display on the external just fine. Now with the internal it's a hit and miss. I sometimes get it from boot. Very rare. But happens. Most of the tiime, when I do the following in this sequence only I get internal screen at the windows login screen. Not at boot. Not at windows loading. But only when the part to ask the password shows up.

This is the order of events that leads to the screen showing up at windows loading:
>Connect VGA cable of external monitor to laptop.
>Turn on external monitor
>Connect power cable to laptop
>Turn on laptop

If I change the order of any of these events, the internal screen doesnt work but external does. I enter the nVidia and/or Windows menu to switch screens and only one shows, that is the external.
If I successfully follow the above order of events, I get both screens in the menus.

Another thing to note. Once I get the display on internal, no physical movement of the internal screen has any effect. The screen works fine. I suspect if the cable were to blame, the screen will go off with moving the lids right? But it doesn't. Only when I restart the laptop, the internal display goes.

Now will you guy still suspect the LVDS cable? Or the GPU? Both will be difficult to get a hands on. Especially the GPU. And that'll be so expensive too. So any quick fixes will be great. I have crossed my fingers and want the problem to be just with the cable so I can get this over with. But you guys are better to judge the issue. Thanks a lot for your time guys. I appreciate it really. I love my laptop. And it's screen is gorgeous. I don't want to lose it.

 

It could maybe something odd going on with the panel electronics, does the machine think the panel is there at all? If you shine a light a the display can you see a feint outline of the actual image (ie it's working but there is no backlight).

 

When it doesn't work, there is not anything on the internal display. Not even a feint outline or anything. Though back a few days when I was testing in a dark room, I felt the screen going from a greyish hue to a dark black when turned on. That means when I turned on the laptop the screen went darker black. The electronics can be the cause. I don't know for sure. My KB lights don't work too. When the display works, nVidia menu shows the internal display. When it doesn't only external display is shown.

I have reconnected the CMOS cell and it's working fine now.

I am clueless because of the lack of parts here. But will try my best to follow all of the steps you provide.

My repair guy said he can open up the LVDS cable to check for damages. Is that safe? Because sometimes the screen does work. I don't want to be left completely in a disaster.

What will you recommend for me to check next?

 

Connect to external display and check with hwinfo under Monitor tab if internal display is shown. This will give you some idea what could be problem.

 

This is a screenshot of my Monitor tab when only the internal display is being used. I don't understand why "Standby" is not being supported. I suspect it's suppose to be like to that.

 

It could have been the CMOS battery going bad causing the firmware to go a little odd, if it continues behaving well I would chalk it up to that.

 

It's not that it is working fine now. I still have the issue. So you recommend trying another CMOS battery?

 

Check the voltage of the battery with a multimeter if you can too and double check it went back in the right way round.

 

I will do that on Wednesday and report back. Got exams. The voltage may cause the screen to behave differently and the lights of the kb not work?

 

It could interfere with the firmware if the bios is being garbled, if the battery voltage is below 2.7-2.8V then it is dead.

 

I just tested it. I couldnt check on the cell directly as the pin connector has a very small hole. But I checked on the motherboard where the cell is soldered. That means the direct solder connection from the connector going into the board.

The reading is in the range of 2.80-2.85 and sometimes 2.88-2.89. Is that the problem?

 

I supposed to be around 3.3v so it's very borderline and worth replacing.

 

Can you tell me what I need to look as specifications of the cell when I buy a replacement? In my country you can't just name the laptop and get stuff for it. So is there something else I need to check on the cell or just that is 3.3v? BTW not sure but my cell has 3.0V written on top of it. Will check again when buying a replacement.

Thanks for your help, man.

 

CR2032 is commonly used, can you check on the surface of the cell to verify?
CR2032 cell battery is typically 3V.
CR2032 battery - Wikipedia, the free encyclopedia

 

Alright. Will go and buy a replacement tomorrow or day after that.

 

Yeah 3v, not 3.3v (I was thinking internal rail of a desktop lol), if it's the right shape it's likely to be the right kind.

 

My prayers have been answered. I haven't changed the CMOS battery yet, but the display is working fine. I still get the same stuff under monitor in HWINFO64. But it's working from boot now. I hope it does. I will not fiddle with it as long as it works fine. If it starts not to work again will try the battery. Please leave this thread open for a couple of weeks, mods. Thanks.

 

The mods wont close threads here, they just expire after a certain time period of inactivity (which is set to several months IIRC).

Glad it's working for now.

 

It's not working today. I am sad again. Let's see if I can get my hands on a replacement CMOS battery soon.

 

Double check the soldering around the battery holder too.

 

This is the cell I found for replacement. Orignally I had a larger one that is yellow in color. It is the default one for an Asus G75. The replacement cell has a voltage of 3.24V. Should I use this or look for something else?

http://imgur.com/PMh7yku

 

Your picture link is broken.

 

Here is the picture.

imgur: the simple image sharer

 

It is about the size of a nickel? Most CMOS batteries are a CR2032 which you can find pretty easily at any place that sell regular batteries. If it was me I'd take the original one apart, find out what battery is in there, replace it, then tape it back together with electrical tape. Only if you're comfortable doing something like that of course.

 

@Hutsady I am comfortable with that too. But this battery I got seems to be smaller than mine. It has a voltage of 3.24. Should I try using this just to check? The connector is the same. Or is it dangerous to use this one?

About unwrapping and changing, what will I need to do? Desolder and resolder the connector wires to the new battery of the same number? If thats the case then I can do that too.

 

So long as the polarity of the connector (which is positive and negative) is correct then the voltage is fine so should be good to use.