Acer aspire LA-5891P try to run

[MDY]

I have a Acer aspire 5741 with motherboard LA-5891P. It tries to run but inmediatly shutdown. Less then 1 seg.
I measure all voltage on coils like RAm, CPU, etc... and I have all voltage except VGA_Core.

When I lifting one side the vga_core coil appears 1.2V for less then one seg and laptop shutdown again.

If I remove CPU, motherboard run and doesnot shutdown anymore. I have all voltage on coils except VGA_core again.

Measuring from VGA_core coil to ground I have 12 Omhnios.
Gpu is 216-0774007. No capacitor shortcut on VGA found.

Any idea?

[Ramee]

Re: Acer aspire LA-5891P try to run

Try first to replace the cpu or flash the bios. see if there's any changes.

[MDY]

Re: Acer aspire LA-5891P try to run

I forgot to write it down before, but I already flash KBC and PCH bios and try another compatible CPU. It is not CPU problem. More ideas?

[Ramee]

Re: Acer aspire LA-5891P try to run

If you have bench power supply, use that. Try to run it without dvd drive, hdd, wireless card, keyboard, internal monitor, modem etc. Just run it with cpu, external monitor, one good memory.

[aanan]

Re: Acer aspire LA-5891P try to run

check cpu core voltage & shorting.

[MDY]

Re: Acer aspire LA-5891P try to run

No shorted on cpu coils. I always run without dvd drive, hdd, wireless card, keyboard, internal monitor, modem etc. I run only motherboard, CPU and RAM. Always. I dont know if it is GPU problem or some shortcut...

[Ramee]

Re: Acer aspire LA-5891P try to run

It could be the GPU, if you have machine, reball it.

[MDY]

Re: Acer aspire LA-5891P try to run

Yes, I have machine. I reballed it and the some problem. I also measure without GPU and I havenot got GPU_Core voltage. I think could be some problem with some powergood signal...Any idea?

[khaahk]

Re: Acer aspire LA-5891P try to run

Maybe discrete gpu will not be turned on at first? If you think it is pgood, then cut the trace to 926 and see if any changes. There is GPIO9 pin on vga, if you try to play with it?
Where did you take the bios from?

[MDY]

Re: Acer aspire LA-5891P try to run

Hi, I get the bios from Acer web page. I checked power supplay for VGA_Core and I do have 19V DCIN but I havenot got nothing on pin EN. What else can I check?