Restart startup too fast to enter boot, cpu fan error shuts down pc. added new fan same error.

[Abink]

had a cpu fan error for yrs, usually hit f2 to bypass. microsoft update seemed to have changed some settings and or restarted my pc. had some usb port trouble on restart but fixed it. 

currently, i no longer have the f2 to bypass option. on restart theres a blue hp screen i hit esc to boot and within 5 seconds the cpu fan error comes on and shutdown my pc. i tried a different fan last month and it worked. now, no fans work. i bought a new fan, same error. 

i need a workaround to get to bios, force windows, bypass the cpu fan error, repair the motherboard sensor manually. replace the bios chip (if theres only one), or a tech store said replace the bios firmware? im not sure how to do that without being able to reach the bios. also can i usb port an update or something before the fan error hits? 

ive spent a week trying to figure this out. 

HP truckee motherboard. american megatrends bios.

[BeemerBiker]

This is an older system and has a number of electrolytic capacitors that are prone to leaking.  I have several of the 1366 socket type motherboards and have had to replace bad caps.

There is a parts list for your system here

https://partsurfer.hp.com/partsurfer?searchtext=hpe%20180t

The 4 pin CPU fan goes into the white 4 pin fan header

The 3 pin is for the exhaust fan not the CPU

AFAICT there are only 2 fans.  

Please verify your motherboard is Pegatron IPMTB-TK

HP part number 594415-001

Do not update the bios if the system is having problems.  

Look at all the brown and black capacitors for bulging  (splitting at top) or leaking

Here are examples  

replace any bad caps before considering bios change.

The only reason to replace the bios is to allow Xeon lower power CPU in place of the I7 Pentiums.  That might not even possible as HP documentation and drivers have been withdrawn.

Go over the motherboard with an air duster.