820 3330

[wirelessplanet]

got a 820-3330 board looks like it had some slight liquid damage.
ppbus is 17.85 which is weird. dunno where to start with this one.

 

[JohnB8812]

Double check that measurement. If it's 17 volts, then Q7030 is shorted. Replace the ISL6259, Q7030, Q7035, and Q7055 at the same time and see what results it yields.

 

[2informaticos]

Q7030 shorted for sure.
Replace it and check C7025.
Be sure to have good solders and traces for U7000.

 

[wirelessplanet]

can i take q7030 q7035 q7055 from a 2011 board? i don't have an 15" 2012 donor board.

 

[2informaticos]

I suppose yes.
Compare datasheet of each component...

 

[wirelessplanet]

replaced q7030 q7035 q7055 u7000
now i have 12.6v but still no boot.

 

[2informaticos]

Tested with 85W charger for sure???

 

[wirelessplanet]

yes sir, always apple store 85W chargers only

i just noticed its 12.6 isn't this gonna be an smc problem? isn't ppubs suppose to be 12.8?

 

[2informaticos]

12.6V is correct value.
Post the basic signals involved in power on sequence.
Also try to start in SMC bypass mode.

 

[wirelessplanet]

schematic says 12.8? is it incorrect?

 

[2informaticos]

12.6V is good value.
Can you post requested signals???