820-00165

[tech]

can you tell me what is
SMC_EXTAL
and SMC_XTAL
also can I measure 12mhz using dso

 

[tech]

I bought a DSO yesterday.

 

[tech]

32.768 OK WHEN PLUGGING
But I didn't get anything on SMC_EXTAL

 

[2informaticos]

Did you check DC level too?
What about other power rails and signals of U5000 (2 OF 2), at page 37?

 

[tech]

all other u5000 required voltages including vddc ok

 

[2informaticos]

3V3_S5 is present?
No 12MHz pulse detected when pressing power button?

What is the actual problem of your machine?

 

[tech]

just pulsing all voltages
when I removed u 1950 all voltages except V core stands stable.

 

[2informaticos]

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?

 

[tech]

voltage pulsing 2 times
VCORE pulsing too
also PLT_RESET_L pulsing
in normal condition

 

[tech]

Resoldered U1950 and removed Q8150 all pulsing but core voltage not coming

 

[2informaticos]

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...