Acer aspire 5520g dead motherboard

[primoz1]

I buy this mboard because mine is in loop (got lights and fan spin for 2-4 seconds, then is restart and again same thing)

This board has no sings of life at all, no lights no nothing.

Where should I look for 3 and 5 in the voltage? Or what must check in this case ?

Thank's

[pctek]

Re: Acer aspire 5520g dead motherboard

First check if there is an input voltage (19V) from the adaptor on the motherboard . Then follow the schematic .

Most of these motherboards that boot in loop can be repaired with reflow/reball . Have you tried it ?

[primoz1]

Re: Acer aspire 5520g dead motherboard

I try reball, even with brand new chip still stay in loop.

I got one big problem when I look schematic I lose myself and do not know where it all began is possible get schematic with fotos like on this picture.

Or if someone could show me in this scheme where to start

[primoz1]

Re: Acer aspire 5520g dead motherboard

I realized that something was wrong on the part of boards to handle the power. There are 19 volts on the power supply.

I also measured a different motherboard, which the pins are missing on nvidia chip, but the rest works.

[b700029]

Re: Acer aspire 5520g dead motherboard

Are you sure the other board "works"? 3.24 looks very close to 3.3 which is what one of the power rails is, with nearly 19V there it is certain to kill components.

The power circuitry is on page 36 of the schematic.

There should be 3.3V across PC18 and 5V across PC27. Measure that first and report back with the results. The standby rail can be measured across PC26 (near PU3) and there should be 5V across it even when the unit is turned off but plugged in.

[primoz1]

Re: Acer aspire 5520g dead motherboard

Hi. I measure this capacitors PC18 and PC27 and no voltage there, also no voltage on all 3 coils near PL6, PL3, PL4.

If work I dont know, but I hope on only dead power part of mboard.

[tw2005]

Re: Acer aspire 5520g dead motherboard

We got a collegues going by heating up the NVIDIA MCP bga chip with a heat gun. Not a professional job but it's been solid now for 3 weeks and gave it plenty of use.

The symptom was it would never boot, it would power on, fan would come on and then as the hard drive spun up to load it would shutdown and go into endless reboot cycles.

We could access this chip by taking the large bottom cover off. Only problem was the guy working on it was impatient and heated it up insitu and melted the battery bay! We did not expect to last but so far so good.

[primoz1]

Re: Acer aspire 5520g dead motherboard

Hi. In my case wont power up and no lights or fan not work, is dead-morto.

[tw2005]

Re: Acer aspire 5520g dead motherboard

Hi. In my case wont power up and no lights or fan not work, is dead-morto.

Yeah, what I was implying was maybe you could get your original one going with reflowing that NVIDIA chip. Thats all, I'm not going to pretend to know what's going on with the replacement. Just passing on what little experience I had with the ACER at work.

[primoz1]

Re: Acer aspire 5520g dead motherboard

Hi. On original I do reball but no help, this board power up OK, but no picture on LCD al all, so I buy other and before I change nvidia chip from this to original board I try find error maybe is some small defect on power part of mboard.