My old HP Zbook 15 laptop sometimes can turn on but sometimes cannot turn on. Can I solve it by myse

[DavidTse]

Hi:

  I have a few HP Zbook laptop. The oldest laptop that I own is HP Zbook 15 first generation. The serial number is CND4120QQK, Product: D5H42AV.  In the last two months, the laptop sometimes can turn on and sometime cannot turn on. When the laptop is one, sometimes the temperature of the base of laptop is hot. At the very beginning, I want to abondan the laptop but I discover some softwares that I am using in the old laptop cannot use on my new HP Zbook laptop so I want to repair the old HP Zbook if I can. Can someone give me information on fixing the laptop so I or HP can fix it so I can use the laptop for a period of time. Thank  you

[Huffer]

HP would not fix it and even if you could talk them into looking at it the cost would be prohibitive. Intermittent power on is very frustrating to diagnose. If you gave it to me to fix I would first open it and check the cooling fan to see if it is clogged by dust and generally clean up inside. I would clean and reseat the memory modules, clean and reseat the heatsink, check the power on switch and try turning it on a few times with the battery removed. Sometimes a bad battery can play havoc with turning on. The fact that it turns on at all means it can likely be repaired but exactly where the issue is right now is very hard to say. 

[DavidTse]

Hi Huffer:

Thanks for your reply. I try to reset the memory modules but the laptop still cannot turn on occassionally after reseating. Note the cooling fan is working and I will clean it up this weekend. I discovered if I open and close the bottom cover , the laptop sometimes will turn on after a few attempts. I expected this related to the spring attached on the bottom cover. However, I don't know how to fix it but I may try to buy the motherboard and turn on parts and replace to my laptop and see does it work.

If you have any suggestion, please let me know. Thank you

David

[Huffer]

There is likely a little plunger button that is held down by the back cover when you put it back on. Keeps the laptop from running with the back off. Those can get sticky and cause problems. 

[DavidTse]

Hi Huffer:

  What does the little plunger button looks like? Is there any way to fix it? If you know why the laptop didn't stop working due to the plunger button, can you please explain the theory behind the relationship between the plunger button and the laptop on off reason or please give me the reference from youtube so I can try to fix it. Anyway, thank you for your information.

David

[Huffer]

It would look like one of those things you put in a turkey when cooking it that pops out when done. Like a tiny syringe. I do not see one noted in the Service Manual. 

Service Manual 

I have the G3 version of the Zbook 15 MWS. Have you run a full diagnostic test on it? You will have the test available in UEFI setup by tapping F2 as you power up. If your notebook does not have UEFI installed there is a bootable diagnostic thumb drive image you can download. Your laptop may not stay on long enough to run it, however. 

[DavidTse]

Hi Huffer:

  This weekend I run a full diagnostic test on my HP Zbook 15. There is no error except my removable laptop battery. The system shows it cannot identify the laptop battery. I want to know what UEFI stands for.  This week, I discover the laptop somtimes can turn on after I press the on button after three times but sometimes cannot turn on even I keep press the on button after I connect the power cable so I think the "starter" of the laptop my have problem.  I still have no idea how to fix my laptop.

David

[Huffer]

UEFI is Unified Extensible Firmware Interface. Some call it "UEFI BIOS" which is not right because your system either has BIOS (Built In Operating System) OR it has UEFI not both. BIOS is legacy = old and UEFI is more modern. It is the control interface that allows the computer hardware to be set up and adjusted even without an operating system. UEFI is graphical; you can use a mouse. BIOS is more like DOS...keyboard input only. 

Let's review what I said earlier:

try turning it on a few times with the battery removed. Sometimes a bad battery can play havoc with turning on

Have you tried running the computer on AC power with the battery removed? Your battery is completely dead. It is not communicating with the motherboard at all. Not certain that is the problem but its where I would focus next. 

[DavidTse]

Hi Huffer:

Finally I spent 5 hours and successfullly completed the extensive test for memory. The system say it passed and I also update the BIOS. Note when the test start the temperature of my laptop is pretty high. However the test cannot identify my DVD rom and my old installed battery. After the test, I try to test the power on button on my laptop and sometimes I need to press 2-4 power on button to turn on the laptop, how can I test the power on component in the UFEI component test? Thank you for your explanation. I learn more about my laptop.