Acer Aspire 8943G Blank Screen

[grahamw01]

Hello everyone,

I have an Acer Aspire 8943G that has failed and now does not show anything on the screen (no backlight too)

I started getting problems when the memory would fluctuate between 8,12 and 16GB on every start up even though the whole 16GB were in. Then sometimes the screen would be a shade of green only and this would fluctuate too.

Now there is no screen what so ever, I have tried all different RAM and even a different CPU with no difference.

I have tried to reflow the graphics chip which didn't do anything (may not have done it for long enough)

I have tried output on HDMI and VGA. HDMI has nothing, but VGA will show hundreds of vertical coloured lines on my TV (quite pretty!). Every time the colours are different too.

Sometimes the laptop will turn off after a few seconds, sometimes it will stay on fine. Sometimes the caps/num lock lights are response and sometimes not.

Hope this information is helpful and someone can help me!

Thanks in advance
Graham

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

The attached pictures are the outputs from VGA.

[henrysin44]

Re: Acer Aspire 8943G Blank Screen

This seems to be a GPU problem, not positive, the fact that your screen comes out like that on an external source says GPU problem. Try getting all dust out of the fans, heat sinks, ect. You will need a heat gun to reflow the GPU for about 50 seconeds to 5 mins. After reflow allow GPU to fully cool then apply new thermal paste to the GPU chip and CPU chip to be save. Hope it works.

More info: http://hackaday.com/2011/02/24/heat-...-fixes-laptop/

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

This seems to be a GPU problem, not positive, the fact that your screen comes out like that on an external source says GPU problem. Try getting all dust out of the fans, heat sinks, ect. You will need a heat gun to reflow the GPU for about 50 seconeds to 5 mins. After reflow allow GPU to fully cool then apply new thermal paste to the GPU chip and CPU chip to be save. Hope it works.

More info: http://hackaday.com/2011/02/24/heat-...-fixes-laptop/

Thanks for your reply, my work place has a proper heat gun for reflow work, I put lots of rework flux under the chip and heated at 500C for about 1 minute and it did not resolve the problem. In every GPU reflow work I have done this has always worked and so far has been a permanent fix. (although the dam air con was blowing directly at me/the chip this time!)

Regards
Graham

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Hi again,

I gave the GPU, GDDR5 RAM for GPU and the BOIS chip (what ever that one is called.. the one that looks like a GPU) a good reflowing today with lots of flux and I am sure if there was any dry joints it would have fixed them temporarily but still it is exactly the same. I *think* the GPU itself is not the problem. After about a minute the GPU is very hot and the CPU is rather hot too, I think much hotter than they should get.

Can anyone help me? I am guessing something has failed on the motherboard. The motherboard model number is DA0ZYAMB8D0.

Thanks!

[henrysin44]

Re: Acer Aspire 8943G Blank Screen

try removing the hard drive and ram. Adding a bunch of thermal paste to the gpu and cpu (not too much though), clean out any dust, and add one removed ram stick to the opposite socket, then try rebooting.

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Thanks, I have tried all of that. There are 4 memory slots, with RAM in 1 or 2 it will do the same thing. In 3 or 4 it doesn't show anything on the VGA output (but I guess it needs something in 1 or 2)

I noticed it I keep trying over and over the laptop will start to turn itself off after a few seconds, I believe because the CPU/GPU are getting too hot and it triggers auto turn off, even though the computer is just probably on the POST screen, where they should not get hot at all.

I think maybe a voltage regulator has gone then or something and sending too much power to the CPU/GPU? Although I am zero good at electronics.

[senchire]

Re: Acer Aspire 8943G Blank Screen

When you say "lots of" what do you mean with that? 500C is way to much for GPU's. I am reballing/reflowing nearly daily, and maybe with that "lots of" flux you melted 2 joins together. Do a reball and see what happens because if the CPU would have gone you would have Black Screen (no boot at all), if ram same or beeps. If GPU / SB you would get these listed up symptoms.

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Thank you for your response, I would not know how to do a reball I am afraid. I do not have the equipment for that! "lots of" flux, I mean I tilt the motherboard sideways and drip flux down until I see it showing at the bottom so I know it is thoroughly covered underneath. I have used the same technique on maybe 10 laptop motherboards before, my friends xbox 360 and my own PS3. As far as I know all the laptops are still good, and the xbox and my ps3 have survived nearly 2 years and counting.

I just tried plugging the internal speakers back in and turned it on with no RAM and it did not make a beep (and nothing on VGA too). Also tried plugging external speakers in.

What is SB?

Regards,
Graham

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

I guess you mean sandy bridge so CPU? I haven't tried another CPU in it (just in case it blows a working one), BUT I have put the current CPU from this laptop in to another and it works fine.

Regards,
Graham

[fddizon]

Re: Acer Aspire 8943G Blank Screen

he meant for SB is South Bridge.

take a mild reflow of it

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Thanks to all who are helping, fddizon, a mild reflow of the socket you mean? I didn't think problems could occur in there, I shall give it a go!

Thanks

[senchire]

Re: Acer Aspire 8943G Blank Screen

Ye south bridge, usually when there are no beeps there is a short and keeping in mind we talk about Acer mostly some chip is gone GPU/NB/SB depends on series. And looking at symptoms which you stated on the begin of the discussion i can assume that some faulty chip is in here, maybe burned GPU with the heat, maybe just SB is gone.

P.S: When i started with reflow/reball did few mistakes with heat and bam, still have these to remind me when you don't watch a MB is destroyed in 1sec .

P.S Just to add, when in future you have such problems better do a mild reflow to see if its a chip.

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Ye south bridge, usually when there are no beeps there is a short and keeping in mind we talk about Acer mostly some chip is gone GPU/NB/SB depends on series. And looking at symptoms which you stated on the begin of the discussion i can assume that some faulty chip is in here, maybe burned GPU with the heat, maybe just SB is gone.

P.S: When i started with reflow/reball did few mistakes with heat and bam, still have these to remind me when you don't watch a MB is destroyed in 1sec .

Well I will try a soft reflow on the CPU socket, it can't hurt to try. Processor is definitely fine as tested in another laptop. Probably will be GPU but I have never broken a GPU with heat.

My first attempt at cranking the temp to 500C was a surprising success. The first reflow work was on my PS3, which was only at 300C for 30 sec to 1 min. I had to reflow it every 2 weeks then it would YLOD. Then 1 week, then 1 day, then 3 times in 1 day. When I did it 3 times in 1 day, the last time I got really angry that it would not fix, so I cranked the heatgun to 500C and heated it for about 5 minutes. I wanted to break it more than fix it that time. I stopped when it set the fire alarm off because I didn't realise chips around the GPU were melting and cracking with smoke coming out. Also the motherboard had swollen and warped about an inch off the table. I put it back together and couldn't believe it worked. This was 2 years ago and it has been absolutely fine ever since!

So any reflow work I did from then on was at 500C. I used to fix a lot of HP Pavillions when they were worth it (since 99.999999999999% broke) and I did all of them with loads of flux and 500C for 1 minute or until the flux stopped bubbling. I used to sell them on eBay once repaired with 6 months warranty and never had a return or complaint!

Anyway, this Acer is my own personal laptop and I can't afford to get a new motherboard for it (they are £170+) I would do anything to get it working

[senchire]

Re: Acer Aspire 8943G Blank Screen

Do not reflow CPU socket you would melt and destroy it + no effect. Second most GPU chips do burn/popcorn if you leave them on high temp long (1st attempt to reball ended with a burned chip 240C for 30sec and caboom).
If you still get these lines etc, you should have try a reflow with a preheater (though dealing with a preheater needs more equipment like TC). I however did few reflows with my heatgun (2months lasted) but i didn't went over 230C. Dunno try SB, but mostly you have 2 or more joins melted together (reball only fix) or could try another GPU reflow, still don't know will it work as you can't properly "nudge" it in the melt stage.

P.S: Like every craftsman doing for others ends up nearly perfect, for your self near destruction of the device mostly it ends like this hehe.

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Do not reflow CPU socket you would melt and destroy it + no effect. Second most GPU chips do burn/popcorn if you leave them on high temp long (1st attempt to reball ended with a burned chip 240C for 30sec and caboom).
If you still get these lines etc, you should have try a reflow with a preheater (though dealing with a preheater needs more equipment like TC). I however did few reflows with my heatgun (2months lasted) but i didn't went over 230C. Dunno try SB, but mostly you have 2 or more joins melted together (reball only fix) or could try another GPU reflow, still don't know will it work as you can't properly "nudge" it in the melt stage.

P.S: Like every craftsman doing for others ends up nearly perfect, for your self near destruction of the device mostly it ends like this hehe.

Is it possible to reball without the correct machinery? Can I just buy a template and some balls, melt the balls to the board then drop the GPU on top? How do I remove the GPU without damaging anything?

Thanks

[senchire]

Re: Acer Aspire 8943G Blank Screen

Indeed its possible but you would need (i have to say this isn't the right method but well without much money to spend its a good solution).

Heat gun (with a controler to set temperature), use it to preheat the board to 150-170C and hold 2 min on the end temp (whole heating lasts 8-11 min). With a SMD rework station (its a must without it its hard), when the bottom gets your desired temp (150-170) use the hot air wand and start the session so :
1. 150C hold 1 min
2. 200C hold 1 min
3. 240C hold 1 min
You need to know which solder is on the gpu leaded gets into melting state at 217C, unleaded at 187C).
You need also a TC or two. Place it near the GPU chip (you only look at his temp that means when top gets 217C we have melting state bring it to 230C do nudge if it moves use vacum pen and lift the chip).
It takes more practice and its a lot closer to failure then to success (but it happens). It fails due the low PH (for which you would use your Heat gun). This is in short how to do it.

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Indeed its possible but you would need (i have to say this isn't the right method but well without much money to spend its a good solution).

Heat gun (with a controler to set temperature), use it to preheat the board to 150-170C and hold 2 min on the end temp (whole heating lasts 8-11 min). With a SMD rework station (its a must without it its hard), when the bottom gets your desired temp (150-170) use the hot air wand and start the session so :
1. 150C hold 1 min
2. 200C hold 1 min
3. 240C hold 1 min
You need to know which solder is on the gpu leaded gets into melting state at 217C, unleaded at 187C).
You need also a TC or two. Place it near the GPU chip (you only look at his temp that means when top gets 217C we have melting state bring it to 230C do nudge if it moves use vacum pen and lift the chip).
It takes more practice and its a lot closer to failure then to success (but it happens). It fails due the low PH (for which you would use your Heat gun). This is in short how to do it.

Oh dear, I don't think I will be attempting this!

I will try to do a standard reflow at 230-240 again today.

[DJduck]

Re: Acer Aspire 8943G Blank Screen

Put a multimeter thermocouple probe on the gpu and preheat at ~220c for two minutes. Then raise the temperature to ~250-260 and heat for two more minutes. Then let it cool down naturally. You can push on the gpu very gently just when you have finished heating. Make sure you put tinfoil around the gpu so you would not damage any other components. You can also give a slight reflow to the gpu memory. The gpu might be dead already, since 500c is WAY TOO MUCH!

[grahamw01]

Re: Acer Aspire 8943G Blank Screen

Put a multimeter thermocouple probe on the gpu and preheat at ~220c for two minutes. Then raise the temperature to ~250-260 and heat for two more minutes. Then let it cool down naturally. You can push on the gpu very gently just when you have finished heating. Make sure you put tinfoil around the gpu so you would not damage any other components. You can also give a slight reflow to the gpu memory. The gpu might be dead already, since 500c is WAY TOO MUCH!

Hi, I tried exactly this tonight, no help. I really think the GPU is just getting too much power because it gets very hot very quickly..

thanks
Graham