Hey everyone - i've been doing this work for a few years now, but have registered because i'm totally stuck on a board.
So I had a guy come in for a battery replacement the other day - i went to plug it in and realised that it wasn't working off the charger either - he hadn't picked up that this wasn't a battery issue.
I swapped in another battery out of interest and it booted up fine - no boot from charger tho, and no charging of the battery.
The Facts
No green light on charger.
SMC reset does nothing.
PRAM reset did nothing either.
Tried with multiple known-good magsafe boards and chargers - all good there.
Customer now believes problem was caused by a knock-off charger.
Absolutely no sign of liquid damage.
With one of my 18.5 volt chargers, i get a random green light, sometimes with a faint ticking sound from the board - the charger looks 100% genuine, but i'm starting to think it is fake because both other chargers give me no green light and no ticking. All three chargers behave normally with other macbooks.
The diagnosis & repair work done so far
I have replaced r7022, r7021, r7086 & r7005 because they were all screwed with high resistance. I have replaced u7000. I also replaced u7200 for good measure.
Since doing the above, the device now boots in SMC Bypass mode with charger, but still nothing otherwise.
Some helpful measurements taken
Resistance between pins 17&18 of u7000 = 3.5Ω
Resistance between pins 27&28 of u7000 = 20Ω
ADAPTER_SENSE = 3.44v
SYS_ONEWIRE = 3.44v
SMC_BC_ACOK = 3.45
PPBUS_G3H = 12.54v
PP5V_S3 = 0.00v
Device still boots perfectly on battery, correctly identifies cycles etc and runs at full speed with normal fans - no boot on charger, and no charge. I'm starting to suspect the SMC, please tell me it's not the SMC, please...
HALP!
Thanks,
V.
So I had a guy come in for a battery replacement the other day - i went to plug it in and realised that it wasn't working off the charger either - he hadn't picked up that this wasn't a battery issue.
I swapped in another battery out of interest and it booted up fine - no boot from charger tho, and no charging of the battery.
The Facts
No green light on charger.
SMC reset does nothing.
PRAM reset did nothing either.
Tried with multiple known-good magsafe boards and chargers - all good there.
Customer now believes problem was caused by a knock-off charger.
Absolutely no sign of liquid damage.
With one of my 18.5 volt chargers, i get a random green light, sometimes with a faint ticking sound from the board - the charger looks 100% genuine, but i'm starting to think it is fake because both other chargers give me no green light and no ticking. All three chargers behave normally with other macbooks.
The diagnosis & repair work done so far
I have replaced r7022, r7021, r7086 & r7005 because they were all screwed with high resistance. I have replaced u7000. I also replaced u7200 for good measure.
Since doing the above, the device now boots in SMC Bypass mode with charger, but still nothing otherwise.
Some helpful measurements taken
Resistance between pins 17&18 of u7000 = 3.5Ω
Resistance between pins 27&28 of u7000 = 20Ω
ADAPTER_SENSE = 3.44v
SYS_ONEWIRE = 3.44v
SMC_BC_ACOK = 3.45
PPBUS_G3H = 12.54v
PP5V_S3 = 0.00v
Device still boots perfectly on battery, correctly identifies cycles etc and runs at full speed with normal fans - no boot on charger, and no charge. I'm starting to suspect the SMC, please tell me it's not the SMC, please...
HALP!
Thanks,
V.