Acer Aspire 4738 dark display after 2 minutes

[mikey5791]

Hi,
This is a previously working Acer laptop
but two months ago it started to show symptom of sudden blank dark display with blue led power and fan still on.
Sometimes it is a blue screen saying i might have changed a hardware, etc...
The whole screen will freeze and i need to press power button to restart. But the same issue of blank display return.

Initially i thought is a heat problem. So i changed to a new thermal fan but the issue is still the same. I also try changing to a different hard disk, reseat the memory card. But the same issue remains. I attached a picture of the motherboard for reference.
On hand i have a dmm, with some basic
soldering skill but i wish to diagnose and repair this laptop if someone is kind enough to guide. Thank you in advance.

[emestee]

Re: Acer Aspire 4738 dark display after 2 minutes

First start the machine, go into BIOS setup and leave it like this. See if gets stuck/crashes/restarts from there. If it does, you know you have a hardware problem. If it doesn't, you may still be looking at a hardware problem, but maybe not.

Additionally test the CMOS battery voltage.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
Appreciate your reply.
I press F2 to enter Bios and leave on. It stays on for more than 30 minutes with no crashes or freeze. Then i exit and restart windows but sadly i can't go into windows screen at all.
It just goes back to the same old error of "windows failed to start. A recent hardware or software change might....

Startup repair also brings me back to this screen over and over again. I can't get into safe mode too.
Testing the cmos battery with my dmm shows 3.10vdc.
Thanks for continue answering my many questions. I hope all your suggestions will bring this laptop to full recovery.

[emestee]

Re: Acer Aspire 4738 dark display after 2 minutes

Boot a Linux live system from USB flash and see if the problem remains when you e.g. open youtube. It's best to confirm this to be a hardware problem before you touch the board.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
Thanks for reply.
Fyi i booted an Ubuntu 8.10 live cd and i choose the memtest86 to test memory. It runs for less than 2 minutes(without completing the test) and goes back to the same blue screen. (A recent software or hardware change.....) I didn't bother to run the live cd since it can't even test the memory.
In your opinion, what should i do next?
Looking forward to your advice.

[Th3_uN1Qu3]

Re: Acer Aspire 4738 dark display after 2 minutes

You have only mentioned reseating the RAM. Try replacing it, I'm fairly sure that's going to fix your problem. That laptop doesn't have a dedicated GPU so that's one failure point ruled out.

Integrated graphics use RAM. Depending on which part of the RAM goes bad, an IGP-based system can pass memtest but be completely unusable otherwise.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
I changed to a new working 1gb ddr3 ram, turned on laptop and checked thru bios.,then restart.
Sadly the laptop boots to the same blue screen saying Windows failed to start. Then i go to startup repair. Not more than 2 minutes, the laptop display just blank. Later i check the start windows normally.
The display goes to blue screen too.
Then i think it is not the ram problem now.
Could be some hardware issue.

Please kindly guide and assist to solve this further. Thank you.

[emestee]

Re: Acer Aspire 4738 dark display after 2 minutes

Could be some hardware issue.

Please kindly guide and assist to solve this further. Thank you.

Start testing the voltages.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi emestee,
Yesterday i removed the non bootable win7 hdd and put in an external case then
perform disk check on my friend laptop which also is running Win 7.
Using the Rebuild MBR feature from his laptop Mini Partition Tool, i finally got my hdd boots into Win 7 and running for hours with no hitch. Voila!
Many thanks to you and others who are helping me to get this laptop running again. At least no need to go for trade in or dump to landfill.

[emestee]

Re: Acer Aspire 4738 dark display after 2 minutes

Don't celebrate just yet, put it under a stress test such as aida64 + furmark.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
Guess you r right on not to celebrate too early because the blue screen appears today displaying the message "A problem has been detected....The system encountered an uncorrectable hardware error. Technical info:
Stop:0X00000124"
So, i removed the hdd and did the rebuild MBR thing but this time is a no success. The laptop can't boot into normal windows 7 but can boot in safe mode.
I have a question here since i not able to boot normal, is there a way i can do stress test using Aida64 and furmark...

[RJARRRPCGP]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
blue screen appears today displaying the message "A problem has been detected....The system encountered an uncorrectable hardware error. Technical info:
Stop:0X00000124"

May be bad CPU caps. (SMD caps on the motherboard, possibly faulty NEC/Tokin caps)

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Start testing the voltages.

Hi Emestee,
How do i start testing the voltages?
On hand i have a dmm and i have basic knowledge on using it.
Please guide me. Thanks.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

May be bad CPU caps. (SMD caps on the motherboard, possibly faulty NEC/Tokin caps)

Hi,
May i know where do i start checking for bad CPU caps since i have no idea. On hand i have a dmm and capacitor meter. Do i need to desolder those smd caps to test it? I am attaching 4 images of the board. Please guide me. Thanks.

[RJARRRPCGP]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
May i know where do i start checking for bad CPU caps since i have no idea. On hand i have a dmm and capacitor meter. Do i need to desolder those smd caps to test it? I am attaching 4 images of the board. Please guide me. Thanks.

Do you on the back side of the motherboard see what look like four rectangular SMD components? (where the CPU is, look on the back side of the motherboard)

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
Fyi, i pulled out the hdd and use Avast to scan virus and found some issue. Avast resolved issue found with Google Chrome. Maybe Google Chrome crashed Windows 7. So i uninstall G Chrome and installed Mozilla Firefox.
Now the laptop seems boot normal and browse ok. I will let it shutdown and restart few times and run it for another week. I hope it stays with the current setting. I will report back soon. Thanks for the great help.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Do you on the back side of the motherboard see what look like four rectangular SMD components? (where the CPU is, look on the back side of the motherboard)

Hi,

Just the second day the laptop can start power on but failed to boot to windows now.
Yes, i saw 4 rectangular smd components on the back of cpu. Marking is 330. Looks like capacitor? Should i proceed to test it using my capacitor meter? I attached an image for reference.
What should i do next? My sincere thanks for patiently guiding me and i do appreciate much.

[emestee]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,

Just the second day the laptop can start power on but failed to boot to windows now.
Yes, i saw 4 rectangular smd components on the back of cpu. Marking is 330. Looks like capacitor? Should i proceed to test it using my capacitor meter? I attached an image for reference.
What should i do next? My sincere thanks for patiently guiding me and i do appreciate much.

These are the tantallums and they do fail sometimes, but you probably should pull them out and not test them in circuit.

[RJARRRPCGP]

Re: Acer Aspire 4738 dark display after 2 minutes

Looks like 3 330uF capacitors.

I have been pondering if overheating would often be the cause of failure...

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,

Are those rectangular shaped caps (marking 330) 33pF? I have not desolder them out of circuit to test yet. I know this has to be carefully done.
Btw, from my area i googled the nearest option to get this replacement(if needed) is ceramic type. I attached a picture for reference. Can this be used as substitute?
Your advice is greatly appreciated.