Acer Aspire 6920 power issues

Orpheous

Distinguished
May 20, 2008
5
0
18,510
A recently acquired Acer Aspire 6920 LF1 is giving me a headache!

I can get it to go into BIOS occasionally, but only when it is running on battery power.
The AC power pack seems to charge the battery ok, as the charging light and blue LED's come on.
When I turn it on with the power pack plugged in, the blue power LED's and the Bluetooth LED's light up briefly, then go out. It then cyclic reboots and the CineDash panel will light up but the screen stays blank.
Sometimes I can get it to go into BIOS when it is running on battery only.
The CPU fan spins ok and power is getting to the DVD drive also.

I've checked the power jack and it seems ok, swapped the RAM out with known working sticks, tried different power supplies of the same voltage/polarity, tried running it on AC only, removed, cleaned and replaced the power connector to the motherboard.

Any ideas?
 
Solution
the problem is the nec tokin capacitor on the motherboard.
I removed this myself after worrying about it and replaced it with 2 x 470uf 2.5 tantalum capacitors i bought online.
you will need though to remove some parts from the laptop to access this capacitor.
if you drop it in to be repaired they will say replace the motherboard which was not a option for me as they are circa 300 euro.

there is another option where you go into the bios and disable the second processor which is causing the problem with throttling and overheating the capacitor.

also try to clear dust and dirt from your internal fan.
just remove the bottom grill and fan is there in front of you and attached by 3 screws

murphyaii

Honorable
Nov 6, 2013
3
0
10,520
the problem is the nec tokin capacitor on the motherboard.
I removed this myself after worrying about it and replaced it with 2 x 470uf 2.5 tantalum capacitors i bought online.
you will need though to remove some parts from the laptop to access this capacitor.
if you drop it in to be repaired they will say replace the motherboard which was not a option for me as they are circa 300 euro.

there is another option where you go into the bios and disable the second processor which is causing the problem with throttling and overheating the capacitor.

also try to clear dust and dirt from your internal fan.
just remove the bottom grill and fan is there in front of you and attached by 3 screws
 
Solution

jensdncaller

Honorable
Nov 28, 2013
1
0
10,510
there is another option where you go into the bios and disable the second processor which is causing the problem with throttling and overheating the capacitor.
gg
 

BlueBeach

Honorable
Dec 10, 2013
1
0
10,510
Hi "murphyaii",
I have the same problem,.....It's been two years now,
After a long reserch (2years ago) found out, if I disable one of the processor, my laptop would get back to work,....... but no body said why,.....
I disabled one of the processor and since then, no problem at all,.......
I really want to fix this problem to get the full capability,.....
I am electronic oriented,......If you think I can do it my self, could you please provide more information about the Capacitors and how to get access to them in the mother board,......any available site???????

Thanks.
 

UKDemon

Estimable
May 17, 2014
4
0
4,510
I had this same issue turned out to be the little bit of plastic with metal on it, the only screw hole for the top plastic by the power button, I have to leave my left side plastic poped up and away from the board underneath slighty to stop it shorting the screen but it works fine if its not clipped down
 

adyordache

Estimable
Oct 31, 2014
1
0
4,510
I have the exact same problem and i'd like to try changing that capacitor but the problem is i can't locate it ...could you please help me with a picture or something like a schematic , a link from where you bought the replacement capacitor ... thank you !
 

UKDemon

Estimable
May 17, 2014
4
0
4,510
I know this is a very late post but I do think these laptops a great bar the problems with them but I agree with bluebeach, I had this same issue with my NEC Tokin chip I did the safe mode trick disabled the 2nd core in device manager and the laptop works perfect now, can still game on it etc, will say though it will have some lag unless you put a SSD in to it seems to compensate abit for the speed lost from the 2nd core being turned off. Otherwise removing the chip is pritty easy I had ago using one of my old boards and a heat gun getting a new one on tho I haven't tried as of yet.
 

UKDemon

Estimable
May 17, 2014
4
0
4,510

Unless you have already found it, the chip is loacted on the back of the CPU plate(back of the mainboard) cant miss it as you can see it on the left when you take the keyboard off big chip with NEC on it