820-00426

came in with no power and spot water damage and corrosion on u7100. replaced u7100 and the corroded resisotors and caps next it to it. now am getting fan spin but no chime. i tried with external monitor as well in smc bypass mode.

cpu-vcore - 1.8v
ppbus - 12.57v

cpu is getting warm.
 

2informaticos

Administrator
Staff member
Did you test for USB activity?
PLT_RESET_L comes high?
Is worth to try known good BIOS.
Also try to start in safe mode.
 
-sorry i did test for usb activity. i get led light on usb drive but no blinking
-PLT_RESET_L comes high? - 3.3v
-i've tried reading the bios, but it keeps giving me an error. i'm suspecting this is problem since i'm having trouble reading the bios chip. do i need an exact match of the bios or can i take one off an 00165 and program it with a 00426 bios.
-booting to safe mode does nothing
 

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2informaticos

Administrator
Staff member
Don't you have a chip from A1502 scrap board?
Check all SPI Bus Series Termination resistors and their traces.
 
I have only one a1502 dead board and i have already used the bios from it.
I checked r6120-6123 + r6130-31 traces to bios chip and jtag and they all have connection and ohms reading is normal on the resistors themselves. Did I miss anything else I should check?

I plugged charger in and they all have power except for r6121 and 6122. neither resistor has any voltage when power is connected. is this normal?
 

2informaticos

Administrator
Staff member
There are more than 10 SPI resistors I think.
I can't confirm if this board is sensitive to exact SPI chip, but is better to discard using original brand code.
 
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