Acer Aspire 5742g turns off but I´m able to enter bios

azigta

Estimable
Oct 23, 2014
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Hi, I reciently got problem with an acer aspire 5742g. It turns off when trying to boot from cd or usb.

I thought it could be a temperature problem so I read on internet about desoldering the motherboard cmos battery for half an hour and placing it back on. I did that.

I also replaced the thermal compound on both cpu and graphics card.

The laptop stills shutting off. I can access bios with no problem, but if I try to boot from cd or usb it just turns off

I updated the bios from version 1.07 to the latest bios wich is 1.30 succesfully, but the problem persists.

Also, recently, the brightness dropped down and I can´t do a thing to solve that...

I think this is a motherboard problem... Has anyone got an idea of what component of the motherboard could be in bad condition? I´m an electronics student and I usually repair motherboards with visible damage (including smds etc.) but with no visually damaged components I don´t have a clue of what is the component that might be causing this.

Is this a common problem? How is it possible to be able to get in the bios but not boot? Untill I try to boot I´m able to access the bios but after that I have to do a discharge of the laptop to be able to access it. It doesn´t make any sense to me. Does anyone know what could be the issue? I´m lost!
 
Solution
Other than the obvious (caps, discolored or blown IC's etc.) I'm at a loss for where to go here. I'm thinking 5v voltage regulation is wonky (or completely shot) which would likely be a very small IC (or more than one). Concentrate around the voltage regulation area is all I can suggest here
Out of curiosity, did you check that the CMOS battery was at 3V? Often (for reasons unknown to me) the computer will act very strangely if the CMOS battery dies
 



Yes, I did check the battery, it was a little above 3v
 
Other than the obvious (caps, discolored or blown IC's etc.) I'm at a loss for where to go here. I'm thinking 5v voltage regulation is wonky (or completely shot) which would likely be a very small IC (or more than one). Concentrate around the voltage regulation area is all I can suggest here
 
Solution


thanks for the suggestion. I´ll look