820-2879b wont fully boot

[Kyle93]

Have a 820-2879 that wont fully boot. When shorting pads i get a fast fan spin after a few seconds and the sleep light blinks 5 times but nothing else happens. Board is in very good condition. No liquid damage. tried good tested ram and tried each ram slot, same results.

What to check first? What do the 5 blinking lights mean?

 

[2informaticos]

Flash new BIOS.
Be sure no corroded traces/resistors around SPI chip.

 

[Kyle93]

Here is backup of BIOS. Can you provide new BIOS?

https://drive.google.com/open?id=1sEACGWAVyIVVu2AMVsGCLAVzaoelkRk0

 

[2informaticos]

Try this as is, do not modify anything.
https://drive.google.com/open?id=1hCTClAnfRLwpGhE6LkfOX2hvmD5JcwXv
If boots OK, then change serial number...

 

[Kyle93]

Tried it but same results. I have also replaced all of the resistors the chip connects to.

What to try next?

 

[Kyle93]

After moving ram around more it booted up but at first started the 5 blink cycle again but then suddenly stopped, chimed and had fast fan spin and a white screen but no question mark folder. After powering off and turning back on back to original problem.

 

[Kyle93]

Only once have i been able to get it to boot all the way to a operating system but now most of the time you just get the 5 blinking lights with no screen and fast fan spin. Im at a lost on this one.

The time it did boot into a operating system i still had the 5 blinking lights before it chimed.

 

[2informaticos]

I don't have 100% tested BIOS.
The one sent to you I got it few years back from Internet...
Try another dump, maybe from an working board if possible.

Fan spins to max could be palmrest sensor issue; try another trackpad and cable.
Clean RAM slots and inspect for cracked solders, especially near the corners.