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820-00165
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These are the SMC connections to external quartz crystal.
It gives better stability to its internal oscillator.
An o-scope can show the exact 12MHz wave, but is not really required.
If you check more working boards, will see there is 1-1.2V DC level, when the oscillation is present.
In similar manner, 32.768KHz crystal can be considered in good working state, if 0.45V DC level is detected on it; valid for Macbook boards!
The o-scope is almost obsolete in the laptop repairs.
Do not believe any super-youtube-technician which presume the use of expensive o-scope for this purpose.
DC voltage measurements help more, when you get experience.
It gives better stability to its internal oscillator.
An o-scope can show the exact 12MHz wave, but is not really required.
If you check more working boards, will see there is 1-1.2V DC level, when the oscillation is present.
In similar manner, 32.768KHz crystal can be considered in good working state, if 0.45V DC level is detected on it; valid for Macbook boards!
The o-scope is almost obsolete in the laptop repairs.
Do not believe any super-youtube-technician which presume the use of expensive o-scope for this purpose.
DC voltage measurements help more, when you get experience.
Did you check DC level too?
What about other power rails and signals of U5000 (2 OF 2), at page 37?
What about other power rails and signals of U5000 (2 OF 2), at page 37?
3V3_S5 is present?
No 12MHz pulse detected when pressing power button?
What is the actual problem of your machine?
No 12MHz pulse detected when pressing power button?
What is the actual problem of your machine?
So 12MHz oscillator is OK.
Resolder U1950 and remove Q8150; test again the board.
VCORE pulsing too?
Check PLT_RESET_L also.
Test starting in SMC bypass mode.
Try to post accurate information.
Voltages pulsing 1, 2 times, or every few seconds?
Resolder U1950 and remove Q8150; test again the board.
VCORE pulsing too?
Check PLT_RESET_L also.
Test starting in SMC bypass mode.
Try to post accurate information.
Voltages pulsing 1, 2 times, or every few seconds?
We discussed many times two pulses symptom on 00165 board.
You should know all to check now.
It is the worst scenario for this board...
You should know all to check now.
It is the worst scenario for this board...