820-00165 Has CPU but no chime or video


This board was cleaned before I got to see it but it looks pretty clean. Probably a spill though. Has 1.8V on CPU. 3.4 on SMC_LID. No chime. No light flash on USB keyboard. Doesn't respond to PRAM reset. No 3.3V on PP3V3_S0SW_LCD_UF. Not sure where to look next.


Staff member
Check if pin 3 of U1950 is high.
Also check if PLT_RST_BUF_L is high too.

Next, check all SPI termination resistors and traces around U6100.


Pin 3 his at 3.4V. PLT_RST_BUF_L is at 3.4V also. So, based on your last suggestion, even with no signs of life with the USB keyboard light, this has reached the SPI ROM stage? In the meantime I'll start the process of checking all of those traces and resistors.