Acer 7736zg No power

[tvlada]

Re: Acer 7736zg No power

I have a 7736zg motherboard with a short on the 3D3V_S0 line. Battery charging is working fine but the laptop won't start.
I've checked the 3D3V_S5 line with U60 removed and it seems that KBC, 3.3V and 5V power source(U62) are working fine. I even get the power LEDs to light up but without U60.
Can anyone point me to where I should search for that short ? I am hoping that the problem is something else than ICH9M.

In the meantime I did the following test: I connected a bench power supply set to 3.3V to 3D3V_S0 line. I slowly increased the current. It stabilized at 4.3 amps. During this time I've checked for parts heating on the motherboard. The only part that did heat (38 degrees Celsius vs 27 the rest of the board) was the nVidia GPU. Is it possible that this could be the damaged part ?

[tvlada]

Re: Acer 7736zg No power

I found the problem. It was the nVidia chip that was shorted. By removing it, the laptop started.
Now my problem is that I will need another mother board. It was my first attempt on desoldering a BGA and it came off along with pads
The good part: I still have 2 more chips on the board to improve my skills on BGA reballing.

[ala_borbe]

Re: Acer 7736zg No power

i have aspire 7736zg with JV71-MV DDR2 that was totaly dead, no lights, no fan, no bat charge

i found U58 (4812B) short and after replace it worked!!!
U64 (4800B) was also reading funny, replaced it to be sure

thanks for the thread and info, hope it helps others

[GlennMueller]

Re: Acer 7736zg No power

I had the same Issues an replacing U58 did the job.
The Notebook aspire 7736zg was not doing anything when connected to Power, whether via Charger or Battery.
When i disassembled the Unit and connected 19V to the Mainboard there was a tiny, barely noticeable ticking coming from the Board.
So THANK YOU for sharing!!!

Glenn

[k370]

Re: Acer 7736zg No power

I had no lights at all, U58 fixed mine. Gate was shorted to Drain. Any idea what is the cause. (My battery is dead!) FYI I checked the other supply lines and saw around 14 ohms on one but it powered up fine. Thanks for the Info.

vary grateful. i have repair one mb thid your tip

[Gazpachuelo]

Re: Acer 7736zg No power

Reviving this old post, just to say that replacing U58 resolve my problem too, also need the replacement of U30 too, seems that U58 its a common issue in this motherboard.