A1278 820-2936-A no power

[hgoncalves]

Hi,

I have an A1278 820-2936-A very strange.

Client reports that it started to become vey slow in macos, until it stoped working.

If If pressure the power button once, the fan spin1 turn and turns off. When trigerring SMC_ONOFF_L, it has the same behavier.

However, if if keep pressuring the power button or trigering the SMC_ONOFF_L for 2 or 3 seconds, the mac turns on and i have display (board alone on bench).

Can you help?

 

[2informaticos]

Check how SMC_ONOFF_L reacts, disconnecting keyboard first.

 

[hgoncalves]

Hi,

It has the same behavier full assembled, w/o the keyboard connected.

 

[2informaticos]

Run corresponding ASD.

Battery is charging?
SMC_ONOFF_L steady 3.3V (in normal mode)?

Check U5010 outputs.

 

[hgoncalves]

Hi,

Battery is charging and SMC_ONOFF_L is 3.454V steady.

U5010:
SMC_MANUAL_RST_L = 2.8V
SMC_RESET_L = 3.424V
PP3V3_S5_AVREF_SMC = 3.3V

 

[2informaticos]

Tried SMC reset and PRAM?

 

[hgoncalves]

Hi, yes, i've tried both

 

[2informaticos]

Run corresponding ASD; lets see if any error pops up.
Fan spins normally?

 

[hgoncalves]

HI,
ASD didn't found any problem, and FAN spins normaly, when it boots. When it doesn't boot, the FAN starts to spin imidiatly when power buttun is presured, and then stops.

 

[2informaticos]

Run HWMonitor and check all current/voltage sensors reported.
See if any value is strange.

 

[hgoncalves]

Hi,
I've instaled a new macOS, but i can't see nothing strange in HWMonitor.
Any idea?

 

[2informaticos]

Is the machine working good, or slow?