Question Asus F5Z long time to see post

[sgcko7]

Dear all,

I have older laptop Asus F5Z. I have and issue with that. When laptop starts it is working completely normal and no issue at all. Yes I used "WHEN LAPTOP STARTS". The thing is when I press power button I hear fan , see lights but completely black screen and then I have to wait 5-30 minutes. After that completely random time laptop starts posting bios and starts as normally laptop would do. There must be something wrong with the power distribution at the start or something like that. Im an electrical engineer I can replace bad parts if needed but I need idea what could be wrong cause I do not have wiring diagram for laptop.
I don't want to throw away that laptop because as I have said when its starts is is working fine even after long time of usage.

For your answers kindly thank you in advance.

Have a lovely day.

 

[helpstar]

Have a look in the BIOS,
Is the boot device selected correctly? Set 1st boot device to "Hard Drive"
Set Onboard LAN boot ROM to "disabled"
Enable RAM/POST Quicktest/quickboot
security options in BIOS:
disable TPM secuity
disable boot sector virus protection

If this won´t work, load manufacture defaults in the BIOS -> save changes and exit

replace the BIOS battery
it´s beside the RAM slots (on the right)
https://www.empowerlaptop.com/wp-content/uploads/2018/good/F5Z-1.jpg

remove the hard drive and check if it posts faster

if more than one RAM is installed, remove one of these and try booting. Switch the sticks if it won´t post faster. Usually one stick has to be in the primary dimm slot and eventually won´t boot at all when only one stick in the secondary dimm slot is installed.