820-00163 No Power


I have an 820-00163 board that has MagSafe, PPBUS_G3H, 3V42, 3V3_S5, 5V_S5, RTC, 3V3_SUS, S5_PWRGD. No SLP. No pulse on 5V_S4. The board came to me after ultrasonic so not a lot of clues. I see slight signs of damage to a capacitor on 3V3_S0 and PPVIN_S5_HS_COMPUTING_ISNS. Everything seems good as far as shorts. None that I can find. Any suggestions for a next step?


PPBUS voltage? Check for short on 5V_S4? Corrosion under SMC is possible. Inspected the usual culprits, U6100/traces, U1950, etc?


• 12.57V
• No short on 5V_S4. Diode to ground is .413.
• Data lines check out. U1950 has 3.42V

Board looks clean. It did spin up once initially. SMC_LID capacitor and resistor area (R5250, C5250) was slightly damaged and repaired by someone else before. I tested it. Working correctly. Has 3.42V.

I'm stumped.