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820_3115-B PLT_RESET_L

KootenayMacGuy

KootenayMacGuy

Member
HI there. I have an intermittent issue with this board that I am able to replicate. Currently its pulling 130ma off the charger @18.5V. There was no liquid damage on this board. If I unplug and re-insert the magsafe (off the DC power supply set @19V) over and over, eventually this board will turn on. When it doesnt turn on, PPBUS_G3H fluctuates 7-9V, and PLT_RESET_L is 0v, all other voltages are within spec. It seems as though it will only turn on with a genuine 85W power supply, and not the 60W. IT will not stay powered on very long running off battery (too low voltage?)

I have replaced:
U7000
U4900
Q7030
Q7035
Q7950

Connecting a genuine 60W magsafe - No boot
Connecting a genuine 85W Magsafe - Boot
DC Power supply set @ 16.5V - No boot
DC Power supply set @ 19V - Boot (but sometimes not)

What should I be checking next?
 
KootenayMacGuy

KootenayMacGuy

Member
Replaced Q7080 and R7025,C7025. Resistance is 3.2ohms@ pins17/18, 20.1ohms @ pins 27/28. This appears to be normal. There is no change to boot (no power up @16.5v) powers up fine @19v. PPBUS+G3H is now normal @12.6v after these components have been replaced. PLT_RESET is still low (0.22v) and the green light on the charger slightly flickers while plugged in @16.5V (the same as when doing an SMC reset)
 
KootenayMacGuy

KootenayMacGuy

Member
3.42 is always present. Board will turn on if I press power button with 60W magsafe connected, just not by itself. Board will boot in SMC bypass.
 
2informaticos

2informaticos

Administrator
Staff member
Board should turn on by itself when charger is connected, if battery is not present.

Do you get now 12.6V at PPBUS_G3H with 60W charger alone?
3V3_S5 and PM_SLP_SUS_L come up?
Just in case, check PCH's RTC signals.
 
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