-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
Macbook A2251 820-01949
- Thread starter ipetro
- Start date
Check diode mode to ground on all secondary power supplies (big coils first).
Which big coils get voltage?
Check for pulse at least; when pressing power button.
Check for pulse at least; when pressing power button.
Any history available?
ipetro
Member
the macbook has not been used for a long time, which is why the battery has swollen and the mac did not charge and did not work. I replaced the battery, it started charging but did not turn on. I checked if it was in DFU and it was in recovery! It recovered without errors but does not show any signs of life. Without a battery, the consumption rises to 20v \ 0.570a and then sharply drops to 20v \ 0.230 and stays there! The board looks perfect, no one opened it before me, there are no traces of spillage inside, although it seems to me that liquid got on the keyboard, but everything is perfect inside
Test the board disconnecting anything from the case.
Just keep USB connector and check CPU voltages.
Just keep USB connector and check CPU voltages.
Do you get all G3S voltages?
Trigger PMU_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
Trigger PMU_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
PM_RSMRST_L must stay high all time.
PM_PWRBTN_L should stay high.
You should catch a drop pulse on this one ONLY when PMU_ONOFF_L is triggered.
PM_PWRBTN_L should stay high.
You should catch a drop pulse on this one ONLY when PMU_ONOFF_L is triggered.
Yeah, PCH instead of PM...
You should note the drop pulse on PCH_PWRBTN_L, when trigger PMU_ONOFF_L repeatedly.
PM_RSMRST_L should stay high at same time.
You should note the drop pulse on PCH_PWRBTN_L, when trigger PMU_ONOFF_L repeatedly.
PM_RSMRST_L should stay high at same time.
"when short-circuited to ground PMU_ONOFF_L"
Do not keep shorted to ground; make just temporarily contact, like pressing power button.
Do not keep shorted to ground; make just temporarily contact, like pressing power button.
"BST" means that is the boost voltage for 1V1 output.
Any high-side MOSFET from a buck-converter, requires (Vout+5V) voltage to control its Gate pin.
That is reached with boost trick.
Did you check again mentioned signals behavior triggering PMU_ONOFF_L?
As I said, do not keep it shorted to ground; just simulate power button press.
That is reached with boost trick.
Did you check again mentioned signals behavior triggering PMU_ONOFF_L?
As I said, do not keep it shorted to ground; just simulate power button press.