820-00164 Green light, fan spin, no dong, corrosion only around BIOS chip

[kevinklinkmuller]

Hi there!

Got a pristine MacBook here, basically has all the signs of booting except it doesn't. The only sign of corrosion is on the BIOS chip itself. Pulled the chip, cleaned and placed back. Same issue.
So I'm thinking I should replace BIOS, but I don't know how that works. I need some sort of programmer to program serial right? I use NAND programmers for iPhones but have never dealt with a BIOS programming. Also, can I use a BIOS chip from a 13 inch air instead and program that?

Thanks!

 

[JohnB8812]

Inspect all traces and resistors near the BIOS could very well be the issue as well. If not, then plenty of people on here can help you fix your EFI

 

[2informaticos]

You should try new BIOS, clean ME.
Search the forum, should be already some link available.
Don't forget to make a backup of your BIOS.

Check first all SPI Bus Serie Termination resistors and their traces.
Also take a look at U1950; post voltages for pins 8, 7 & 3.
Do you get VCORE?