820-4924 - green light, no liquid damage, sudden shutdown.

Rozakis

New member
Hello guys,

I got a 820-4924 macbook that has no signs of liquid damage. The customer brought it because it was shutting down out of nowhere. What should I measure first?

Thank you
 

2informaticos

Administrator
Staff member
First of all check 3V42 and PPBUS_G3H.
Do you get amber light on Magsafe connector?
Next check 3V3_S5/SUS.
ALso check for any pulse on big coils.


BTW, use Magsafe 2 charger, not 1 --> 2 adapter.
 

Rozakis

New member
Hello,

amber light on Magsafe connector OK. PPBUS_G3H 12.51V, pp3v42 3.39V.

I don't know what the /SUS part in 3V3_S5/SUS is, can you explain?

Also, I have no oscilloscope to check for pulses... is there any other way?

Thank you
 

2informaticos

Administrator
Staff member
Check for pulses means to check if you get any voltage pulse; no need an o-scope.
Of course, o-scope is better, but not really needed to see if a voltage tries to appear.

3V3_S5/SUS means 3V3_S5 and 3V3_SUS; usually we try to write the essential...
 

Rozakis

New member
Thank you for clearing that up. Big coil L7520 seems to give a tiny voltage 0.02v at initial contact, but then drops to zero. Big coil L7130 is 12.50V.

Measured PP3v3_s5 is 3.32v and _SUS is 0V


Kind reminder, the Macbook is not steady. Sometimes it will not boot at all; other times it boots but shuts down after some seconds and other times it boots into the operating system and can work for several minutes.
 

Rozakis

New member
Client says it has not been dropped but who knows, right? Unfortunately, even in SMC bypass mode it does the sudden shutdown...
 

2informaticos

Administrator
Staff member
Try only MLB on the desk; RIO board disconnected.
Just use an USB mouse for test, or USB OSX with Link LED.
 
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