Acer aspire 6920g - no display issue after fix

[murphyai]

I have a acer aspire 6920g that i'm trying to repair for a friend.

It kept restarting all the time.

so i proceeded to change the nec tokin oe907 chip on the motherboard with 2 x 470uf 2.5v capacitors

since i've done this the battery is now charging when it wasn't previously but the screen will not appear from the vga display on the motherboard.

I forgot to put thermal pads back on the gpu when i was putting it back and used only thermal grease.

anyone any ideas?

[dj_ricoh]

Re: Acer aspire 6920g - no display issue after fix

use 4x 330 always go higher

[murphyai]

Re: Acer aspire 6920g - no display issue after fix

i don't think that is the solution

oe907 is 900

2 x 470uf is 940 so it is higher.

i previously tried 4 x 470uf and that was too much

also battery was not charging with 4 capacitors but it is now with 2

any other ideas community?

[trebo]

Re: Acer aspire 6920g - no display issue after fix

any other ideas community?

high esr caps maybe,
or no continuity between the two positive ends that some MBs don't seem to have

[murphyai]

Re: Acer aspire 6920g - no display issue after fix

if there is no positivity between the positive ends how come the battery is charging now?

[rievax_60]

Re: Acer aspire 6920g - no display issue after fix

The NEC/TOKIN capacitor filters the CPU's Vcore voltage.

[jtamad44]

Re: Acer aspire 6920g - no display issue after fix

i don't think that is the solution

oe907 is 900

2 x 470uf is 940 so it is higher.

i previously tried 4 x 470uf and that was too much

also battery was not charging with 4 capacitors but it is now with 2

any other ideas community?

Why don't you try to put 3 x 470uf see what happen.

[Francisco.s]

Re: Acer aspire 6920g - no display issue after fix

so i proceeded to change the nec tokin oe907 chip on the motherboard with 2 x 470uf 2.5v capacitors

since i've done this the battery is now charging when it wasn't previously but the screen will not appear from the vga display on the motherboard.

Nec tokin, filters cpu core voltage, but circuit charger should work in stand-by. (no need cpu)
Can you charge the battery and check if laptop woks properly with it?

[murphyai]

Re: Acer aspire 6920g - no display issue after fix

i'll add one more capacitor later on.
then charge the battery and try to boot off it.
don't see how the capacitor would affect the video though

[dj_ricoh]

Re: Acer aspire 6920g - no display issue after fix

i'll add one more capacitor later on.
then charge the battery and try to boot off it.
don't see how the capacitor would affect the video though

if i take the cpu from my working notebook... will it work?
so if the voltage its not powering up the cpu will it work?

[rievax_60]

Re: Acer aspire 6920g - no display issue after fix

i'll add one more capacitor later on.
then charge the battery and try to boot off it.
don't see how the capacitor would affect the video though

When you are asked to check continuity between the end strips, do you know what is meant?
Why do you keep ignoring something that is simple and might be important?
What do you normally repair as a professional tech?

[murphyai]

Re: Acer aspire 6920g - no display issue after fix

to check continuity do i need a multimeter.
i don't usually repair motherboards at component level.
i fixed network and software issues usually

[jtamad44]

Re: Acer aspire 6920g - no display issue after fix

here

http://www.ebay.com/itm/Fluke-115-Di...-/170707010480

[murphyai]

Re: Acer aspire 6920g - no display issue after fix

well, i took out my motherboard yesterday and placed it in the oven at 220 degrees for 10 minutes

battery started to charge and work on it's own after that.

but still no video.

haven't got around yet to testing the charge

[kostas-]

Re: Acer aspire 6920g - no display issue after fix

I have the same problem on the same model (acer aspire 6920g). Had random restarts and i replace the NEC/TOKIN 0E907 with a new one. After i replace it i have no video (laptop screen, VGA and HDMI).

I test other NEC/TOKIN, cpu, memory and MXM graphic card but the problem still exists. So the problem must be on m/b. I test it only with m/b, cpu, memory, graphic card, fan, power button and an external monitor via VGA port. I try to power up the laptop while pressing the north bridge chip (Intel LE82PM965) with no result. In case suddenly the chipset fail (i know not the best way to test it).

Before, the laptop was working and the only problem was the restarts. I disabled the second cpu core from device manager and working without any problem. So i decided to replace the NEC/TOKIN.

I have a multimeter. How to check continuity between the end strips as mention above? I'm not sure i understand it. The voltage on NEC/TOKIN is 0v on both sides. Also, the cpu and chipset never heated.

If i put 4x 330uF 2.5V tantalum capacitors it is possible to fix the problem? If the NEC/TOKIN removed, the laptop behave this way (no video)?

Any ideas or advices?

[ala_borbe]

Re: Acer aspire 6920g - no display issue after fix

i had similar problem with toshiba, there is a post somewhere, talantum order from ebay was bad, replaced with used from dead motherboard and it worked

you can also use 6x220 2.5v
worked for me anyways

[kostas-]

Re: Acer aspire 6920g - no display issue after fix

Thanks for the reply. I'll try the smd tantalum capacitors. But i'm afraid it's something else.

[kostas-]

Re: Acer aspire 6920g - no display issue after fix

I replace the NEC/TOKIN with 2x 470uF caps (used from other laptop). Also, replace the core voltage controller (ADP3208) and two mosfets (Si7686DP).

Now with the cpu attached when you press the power button the power light opens for a second and turns down. Of course no video. Also, the fan try to spin but stop immediately. Without the cpu the power light remains open and the fan spins.

I check all the system voltages (5V, 3V, 1.5V, etc) and it's ok. I test with other cpu and graphic card with the same results.

Any ideas?