Laptop doesn't turn on after re-assembl​y and replacing thermal paste. Please help!

Question

Hi,
I hope anyone can help me. I took apart my laptop HP HDX16 to replace thermal paste and clean up the fan. I did everything very carefully as showed in manual. I cleaned the old paste and pads off and replaced thermal paste but not the pads as someone in the store suggested that there is no need for putting pads and that the thermal compound is enough to have it on there. I left only one pad on the heat sink in place where it services Northbridge as it was in good condition. On the Northbridge itself I put thermal compound as well as on the GPU and CPU.  I put back every screw and connected each cable as it was before (I am pretty sure about it). I was quite happy with my job but after I tried to turn the computer on it wouldn't start at all. Did I do something wrong? Please help me because I don't have any idea what to do now.

Answer 1

I am a little confused here, it sounds like you removed all the thermal pads except for one, if this is so, you need to put all the thermal pads back in place.
 Anyways aside from that, if you plug the adapter in you will have a steady light where it plugs into the laptop. The light will always be on whether the machine is booted up or not.
 If you don't have a steady light then you need to check the DC receptor where it plugs into the MoBo. Sometimes a cable may look like it's fully seated, but isn't. It still will boot up with the battery in place even if the DC jack plug is not correctly seated.
 Check the small ribbon cable on the power button board where it connects into the MoBo.
 Check that the processor is correctly aligned with it's key and that the locking mechanism is fully locked.
 Make sure the RAM is seated correctly.
 If these suggestions sound obvious, I have to start some where.
  The problem here is that only you can help your self because you disassembled you machine, I can only make suggestions as what you may have missed and obviously something was missed.
 If your thinking that you incorrectly applied the thermal paste, then that's not the problem. Even if there were no thermal pads or paste in place, the machine would still boot up, but it would heat up very quickly.
 If the fan plug was plugged in incorrectly you would get a message in the BIOS upon boot up saying that the fan has a problem and it would shut down, but it sound like it's not even getting that far.
 There is also a secondary fan that is used to cool the hard drive bays, check that plug as well. You may not get a BIOS message if this fan is not plugged in.
 Here is the HP Media Services Library, you may find it helpful. Make sure you're signed in before clicking on the link.
 http://h20574.www2.hp.com/default.htm?lang=en&cc=U​S&hpappid=psml
 If you need help with the library, post again, give the video page time to load, the small video screen may stay black for a little while.