Lenovo Z570 will not POST

drewerd615

Estimable
May 21, 2015
3
0
4,510
Okay so...

A few weeks back my Lenovo Z570 laptop died. I had just opened a new browser tab, and everything suddenly turned off. Instant black screen, not even a gradual shutdown. I tried rebooting, and looked up several tricks such as the 'hold down the power button for 30 seconds for 30 times', nothing worked.

I then took apart the laptop. I isolated every component until I was literally left with just the motherboard. I found out with the use of a voltmeter that the board was likely the issue. An IC on the board was unusually hot, and the readings on the meter were pulsing like something was overloaded, preventing a boot.

I went on eBay and bought a new board. For anyone interested: http://www.ebay.com/itm/New-Orig-Lenovo-Ideapad-Z570-GT-540M-Montherboard-48-4PA01-021-N12P-GS-A1-LZ57-/141571831179?ssPageName=ADME:X:RTO:US:3160

The first board I received appeared to be faulty. It was an improvement over my original board because I could see the LEDs lighting up, and there was more of a response than with the original board. The CPU fan would spin for 3-5 seconds before stopping, and I would get no POST. This board could detect, although very quietly, when the RAM was in and when it was not in. I put my ear by the speaker and could hear a faint RAM issue sequence beep (1, 3, 3, 1). I tried unplugging the CMOS battery to reset BIOS settings, no luck. I then realized slight pressure to certain parts of the board killed its power, so I assumed there must have been cold solder joints.

I ended up RMAing that board and the seller sent me a replacement, which I received this morning. I installed the new one, and... I have the EXACT same problem as with the first replacement.

This leads me to strongly suspect the CPU. Before I buy a new one, I am curious if there are any other things I can try. I have never been so stumped on fixing a computer as I am now.

The problem is not:
- The RAM. I took both sticks out and my friend booted up with them in his laptop, everything was fine.
- The PSU. Tested with meter, correct numbers.

The problem could be:
- The motherboard. I find this unlikely that I would receive a second motherboard with the same exact symptoms as the first attempted replacement.
- The CPU. I have heard that this is rare, but I do think I have symptoms of a bad processor.

Specs:
Intel Core i5 2450m 2.5GHz
Nvidia GeForce 540m
8GB DDR3
750GB HDD

Thanks,
Drew