HP dv6-7010us POST issue

[AJMD]

Hello Community!

We have a client with a dv6-7010us running Windows 10 Home x64 (BIOS version F.23 or F.25a I believe). Her laptop was getting too hot for her liking, so I disassembly, cleaned and replaced the thermal paste, cleaned the fans, and reassembled. 

System will no longer POST (Caps lock white flash every second and solid amber Wi-Fi light). HP support documentation would point to a CPU malfunction. Our shop has many spare parts so we replaced the A8-4500M with no change. We then found two donor motherboards from dv6-7010us. These also had A8-4500M CPUs installed. Unfortunately, we don't have the history of these donor motherboards, but we tried every CPU in every motherboard. All combinations would not POST with the same LED error on keyboard. We also replaced with RAM and CMOS battery for good measure with no change.

At this point we gave in and purchased a working dv6-7010us. This laptop had a hard drive with Windows 7 installed. All hardware scans passed (PC-Doctor v12). The laptop wouldn't boot to the original Windows 10 hard drive, so we upgraded to the newest version (F25a I believe). This fixed the boot problem and everything seemed hunky dory. All hardware scans passed.

Now here is where we should have stopped...BUT that client paid for new thermal paste and she sure as heck wasn't going to get a computer back without it (because who ever heard of an HP computer getting overly hot......sorry HP).

We now have the exact same problem. Now, I know you may say that we could have shorted it out, or that it's a coincidence, or that all the motherboards could have burnt out GPUs/CPUs/Chipsets, but I am skeptical. We've tried downgrading the BIOS, with no success. 

Our experience and the evidence points us towards the BIOS chip (maybe the new version in such an old laptop), and when disassembling and removing the CMOS battery, something resets and the BIOS chip or something else board level gets corrupted. 

Has anyone else experienced anything similar with this model laptop? Between the three of us, we fix ALOT of computers, and when tend to not encounter these kind of problems on routine procedures. 

Thank you fellow technicians, support staff, and tinkerers.

[Riddle_Decipher]

@AJMD I must say that HP does not recommend changing the thermal paste or any hardware component as it may render the device unstable, that said, going by your description of the issue, this looks like an issue with the BIOS/Motherboard, and if you've already attempted the steps to recover a working BIOS using the steps mentioned here and yet the issue persists, we could be looking at a hardware malfunction and I suggest you talk to HP support and discuss your options, follow the below steps to get started:

1) Click on this link - http://www.hp.com/contacthp/

2) Click on Sign-in or select the product using the below step:

3) Enter the serial of your device.

4) Select the country from the drop-down.

5) Click on "Show Options".

Fill the web-form, to populate a case number and phone number for yourself!

Also, if you are having trouble navigating through the above options, it's most likely because the device is out of warranty, if yes? please send me a private message with the region you are contacting us from, 

here's how private messages work: Click here for details.

P.S: Welcome to HP Community 😉

If you wish to thank me for my efforts, you could click on "Accept as solution" on my post as the solution should help others too.