Laptop boots intermittently

[MrBojangles]

The subject: Asus K55VM

The problem: Doesn't boot. No lights, no fans nothing.

Troubleshooting: I notice when I plug in the adapter that the light on the adapter goes out. OK. I remove everything including proc and external gfx. I plug in the power and again the light goes out. I figure its a bad MOBO and order a new one.

New mobo comes in. I test plugging in the charger, light stays on. Great. I assemble processor, external graphics, ram and CPU fan. Light on charger stays lit and the little green LED on the laptop is lit (although very faint, I must add).

Okey so I reconnect the keyboard so that I can press the power button which is situated on the keyboard. It doesn't work over and over. I dont know if this did it but I popped out the CMOS battery and put it back in and I THINK that it started up right after that (I dont remember since I tried booting so many times). All the proper lights go on and the green LED indicating power that was very faint becomes normal-strong. Fans spin but the screen shows nothing. No beeps. I managed to get it to power up maybe 3-4 times out of 50 or so tries.

Possible problems:
CMOS Battery? (I also tried the battery from the broken MOBO)
Wrong mobo? The Mobo I needed is called 60-N88M-1102-c04 but I only found mobos called 60-N88M-1102-c06 (the 4 becomes a 6). Could that be it? I figured its not a big deal.

This is my first time ordering such an expensive part (100 usd) so I'm a little anxious that I screwed up in some way...

 

[glennd]

Charger

 

[MrBojangles]

Forgot to mention, already tried another working charger

 

[katz]

Are you experienced with working on laptops? I would suggest going over everything again, connections, and especially the screws to make certain that you might not have a longer screw in one of the holes that may be shorting something.

 

[MrBojangles]

I got the board out completely. Only CPU, GPU, ram and CPU fan are connected. The only screws connected are the screws to hold down the heatsink.

Could it be that I ordered the wrong model??

Or could it be that the CPU or GPU ALSO failed? If yes, which is more likely to fail?

 

[coffee]

I would also entertain the idea that you got a bad board. It happens and can be pretty frustrating. Return the board for a replacement.

 

[katz]

If you try to boot with the ram pulled, you should get 3 beeps I think, which it a crude test to see if the motherboard is at least "semi" functioning. Is this a "new" board, meaning brand new, not used? If it is an ebay/other used board, look over everything carefully, make sure none of the ports are damaged, i.e. usb bent pins, etc.

If all that checks out, I'm leaning towards a bad board as coffee mentioned. It happens - I put together a high end gaming desktop pc a couple of years ago with an expensive ASUS board, and it gave me several crazy issues right out of the box. I determined that the board was bad, egg sent me a replacement and it booted just fine.

This is the kind of stuff that can make you second guess your tech prowess, lol..

 

[MrBojangles]

Yeah katz this is really frustrating I must say. Meanwhile I got a client asking me when his computer is ready and I really dont want to tell them that I have to return the board and order a new one etc. etc. Plus I lose on the shipping :/

But here's some news. So I gave up on the power button on the computer and started shorting the power switch itself. I can pretty reliably get the computer to start up now. I got no display though, not onboard or external. Tried VGA and HDMI. So I got lights, fan, heat coming from processor but no display.

Whats the most likely problem:
* Bad board
or
* GPU / CPU? I can't imagine a motherboard breaking and taking a GPU / CPU along with it at the same time. Or maybe the GPU broke and took the MB with it?

 

[MrBojangles]

Okay I'm thinking of returning the mobo if nobody else has any suggestions?

 

[MrBojangles]

Okey problem solved!

Luckily I got another laptop in which had a processor with the same socket so I completely dissasembled it and tried the other processor. Yup it worked. So I told the client and am now ordering a new processor.

Wow I never thought that the processor and the motherboard would both die at the exact same time. I also didn't think there was more than a 1 % chance that it was the processor but there you go. A lesson well learned for the future to keep processors around for testing. Too bad recent processors are so expensive :/