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Macbook A2141 820-01700 No Response to Amp Meter
- Thread starter Instafixx
- Start date
What is the exact ohm value of that short?
Compare with the readings on all big coils.
Don't forget L9080/580...
Compare with the readings on all big coils.
Don't forget L9080/580...
Don't touch U7000 yet.
Did you do what I said about the coils from secondary power supplies???
Remove F7000/1 and check which side the short remains.
Did you do what I said about the coils from secondary power supplies???
Remove F7000/1 and check which side the short remains.
OK, check all other big coils.
What is C7050 voltage, with both fuses removed?
What is C7050 voltage, with both fuses removed?
What do you expect, if is connected to PPBUS_G3H???
I said to compare short value with the readings on all big coils to ground.
I said to compare short value with the readings on all big coils to ground.
I doubt you get so high values on CPU/GPU coils.
Please, post exact reading on each coil.
Please, post exact reading on each coil.
You couldn't find all of them?
Where are the mentioned GPU and CPU coils readings???
GPU coils are hidden under black plastic, in the middle of the board.
Use boardview, please.
BTW, no need to check on both pins of a coil....
Where are the mentioned GPU and CPU coils readings???
GPU coils are hidden under black plastic, in the middle of the board.
Use boardview, please.
BTW, no need to check on both pins of a coil....
I said to compare with the reading on PPBUS_G3H side.
If no close reading value, then is safe to apply voltage injection method.
But you MUST be very sure have checked ALL coils.
And is not the case here. you still miss some of them!
Really, didn't see L3500, LB700, LA860/70, LA950, L7330, LA750, L7211, L7410???
Of course, check only ONE coil when you have more tied together...
If no close reading value, then is safe to apply voltage injection method.
But you MUST be very sure have checked ALL coils.
And is not the case here. you still miss some of them!
Really, didn't see L3500, LB700, LA860/70, LA950, L7330, LA750, L7211, L7410???
Of course, check only ONE coil when you have more tied together...
Seems that you have luck; no short between PPBUS_G3H and other secondary power rail.
I hope you've posted correct readings.
Now you can inject 1V into PPBUS_G3H and see what gets hot.
Using IR thermal camera helps you a lot.
Set lab PSU at max current limit.
5A PSU may not help, but try if no better available.
If 1V doesn't help, slowly increase the voltage.
With such pure short (0.001), 1-2V should be more than enough to detect the culprit.
I hope you've posted correct readings.
Now you can inject 1V into PPBUS_G3H and see what gets hot.
Using IR thermal camera helps you a lot.
Set lab PSU at max current limit.
5A PSU may not help, but try if no better available.
If 1V doesn't help, slowly increase the voltage.
With such pure short (0.001), 1-2V should be more than enough to detect the culprit.