POWER RAILS in order to turn it on the mac help

[Juank]

I am a Litle confused because I see the POWER RAILS but I don know which has to be present before and after turning on the machine I know some voltage is Always-Present but which one not?

 

[dukefawks]

G3H rails are always present. S5 rails are present with AC connected. The rest will come on as the macbook turns on first S4 then S3 and last S0. Once S0 is present the very last voltage will be CPU Vcore to come high.

 

[Juank]

No Title

Thanks for your answer I ask these because I have one Mac book pro <a href="tel:820-2532">820-2532</a> I have PP3V3 S5 but I don’t have PP5V S5 and both came from the same IC but I don have short to ground in the coil L7220 and I don’t know if I have to make another post for these question?

 

[dukefawks]

L7220 is the 5V power supply and is a S3 rail. Common problem on these boards is C7771. What is the voltage on C7771? Are you using a REAL Apple 85W charger?

 

[Juank]

No Title

Hi again about your questions yes I have the original charger on C7771 I have 1.1v and let me explain to you a little more about these Mac one repair shop give it to me and they say the only thing what they found is these .

check the picture is a small coil burn L3405 and that one suppose to have PP5v_S3 and like you say is goin to be present after the mac turn it on So something el is missing can you tell me what I have to check next because I have the voltage on

SMC_ON OFF 3.3
G3HOT
PP3V42

and thanks again ..

 

[dukefawks]

L3405 burned because of a short in the cable to the airport card or airport card in LCD they plugged it in upside down. L3405 has no effect on the power on of the board.

SMC_ADAPTER_EN present? Green light present?

 

[Juank]

Yes I have SMC_ADAPTER_EN 3.3v and Read Ligth Present what other signals I have to check and how I have know the signals What I have to follow In pc is easy to me I check the signals in KBC I know there what I have to do but apple is totally different I am a little confused

 

[dukefawks]

PM_PWRBTN_L toggling when you press the power button? PP3V3_G3_RTC present? 32kHz present on Y2810?

 

[Juank]

No Title

Sorry about the delay to answer your question but I didn’t have te equipment to read the frequency on Y2810 about both questions yes
1) I have the frequency on Y2810
2) when I press power button PM_PWRBTN_L drop to 0 v but nothing else

 

[dukefawks]

MCP is now a primary suspect, SMC is next. I assume you checked all rails for shorts?