820-3476, small water damage around u6100 bios chip, now cant boot fully

ielectron

Member
So c6100 was corroded and kinda fell off the board, that is around u6100, the board doesnt look bad, always starts up with chima, it will start to boot, and the line under the apple logo just about to finish, than it powers off, in boot menu holding option key is the same, new battery and new SSD with installed osx,s still the same. Now i think it will be the u6100 bios chip, we have 2 donor boards, one of them have a good loking u6100, but atm i dont have the programmer, do i start that way? to remove u6100, read it out and program the bios chip, or if the bios chip is damaged it would not even try to boot?
 

dukefawks

Administrator
It's not the chip. Check all traces and termination resistors (16 of them). Also inspect U1900 and U1950 for corrosion.
 

ielectron

Member
16? in the schamtics on the 45. page , SPI Bus Series Termination, is see like 14 of them, but some of them are not installed, even on the 2 donor boards i have, like r6130 is not present on any board i have , nor r6131
 

ielectron

Member
i checked aroun u1900 and u1950, looks pretty good, no corrosion, now i found another capacitor, it was corroded and broke off easily, c1801, that is filtering the pp1v05_s0
 

ielectron

Member
i took off the bios chip to see corrosion, but that is fine, i put it back, same thing, than SMC reset, works, charger light changes to green, but PRAM reset wont work, maybe it does not have time to finish, same with usb keyboard, and now after tryin pram reset a few times there is only backliht and chime, but no apple logo, now i cant even go into the boot menu, i powers off in about 10 sec
 

ielectron

Member
i tried it with everything disconnected but the lcd, battery, doing the same, even without the SSD or with another ssd, , after the battery was removed and plugged in again with the charger the board will start up by itself once which is normal, i dunno maybe i will keep it for a little while, and than close it.
 
Top