Hi guys,
first of all, thanks for taking a look at this. I've watched a lot of Louis's video's, but this is my first actual board I'm fixing. there was heavy liquid damage near the LCD connector, so i first replaced U9000, q7920 and c9009. The onewire circuit worked because i had/have a green light on the magsafe, but no fan spin. I diagnosed pp5v_s5 not being present, so i replaced u7200. now I do have pp5v_s5, and my fan spins for a second before it stops, then starts again. that continues in a cycle. I also replaced c6601 because I knocked the original off the board. Now the next signal that is not present is pp5v_s3. (I'm also missing pp3v3_s3) and the corresponding s0 rails but that seems logical to me since i dont have the S3 rails.
The part where I am stuck is this:
from what I understand from the schematic, u7200 creates pp5v_s3, but something has to happen with Q7260 and Q7261. Now what exactly that is, I don't know. I vaguely remember Louis has a video describing what an N channel mosfet is, I can't find the specific video anymore though.
I do have 12.5v on pin 5 of q7260. Some additional measurements:
rail should be is diode mode
ppbus_g3h 12.8 12.5
ppbus_s5_hs_computing_isns 12.8 12.5
ppbus_s5_hs_other_isns
PP3V42_G3H 3.42 3.47
ppvrtc_g3h 3 3.30
PP5V_S5 5 5.01
PP5V_SUS 5 5
pp5v_s3 5 0 0.100
pp5v_s0 5 0
PP3V3_S5 3.3 3.3
pp3v3s4 3.3 3.3
pp3v3_s3 3.3 0
PP3V3_S0 3.3 0
PPVCORE_S0_CPU 1.25 0
PPVCORE_S0_AXG 1.05 0
PP1V5_S3_CPU_VCCDQ
Can anyone please point me in the right direction? Or knows what the video is where Louis explains the mosfets? Wikipedia and the likes only talk about substrates and chemical blablabla, which is all way above my college dropout mind. Thanks in advance!
first of all, thanks for taking a look at this. I've watched a lot of Louis's video's, but this is my first actual board I'm fixing. there was heavy liquid damage near the LCD connector, so i first replaced U9000, q7920 and c9009. The onewire circuit worked because i had/have a green light on the magsafe, but no fan spin. I diagnosed pp5v_s5 not being present, so i replaced u7200. now I do have pp5v_s5, and my fan spins for a second before it stops, then starts again. that continues in a cycle. I also replaced c6601 because I knocked the original off the board. Now the next signal that is not present is pp5v_s3. (I'm also missing pp3v3_s3) and the corresponding s0 rails but that seems logical to me since i dont have the S3 rails.
The part where I am stuck is this:
from what I understand from the schematic, u7200 creates pp5v_s3, but something has to happen with Q7260 and Q7261. Now what exactly that is, I don't know. I vaguely remember Louis has a video describing what an N channel mosfet is, I can't find the specific video anymore though.
I do have 12.5v on pin 5 of q7260. Some additional measurements:
rail should be is diode mode
ppbus_g3h 12.8 12.5
ppbus_s5_hs_computing_isns 12.8 12.5
ppbus_s5_hs_other_isns
PP3V42_G3H 3.42 3.47
ppvrtc_g3h 3 3.30
PP5V_S5 5 5.01
PP5V_SUS 5 5
pp5v_s3 5 0 0.100
pp5v_s0 5 0
PP3V3_S5 3.3 3.3
pp3v3s4 3.3 3.3
pp3v3_s3 3.3 0
PP3V3_S0 3.3 0
PPVCORE_S0_CPU 1.25 0
PPVCORE_S0_AXG 1.05 0
PP1V5_S3_CPU_VCCDQ
Can anyone please point me in the right direction? Or knows what the video is where Louis explains the mosfets? Wikipedia and the likes only talk about substrates and chemical blablabla, which is all way above my college dropout mind. Thanks in advance!
