A1286 820-28-50A no power

[hgoncalves]

Hi,

Hi have an A1286 - 820-28-50A, that has green light, but no fan spin and only pulls 0.040A from the bench PSU.

All big coils are 0V, and on diode mode I get:

L7630 = 0.0194V
L 8920 = 0.0057V

Are those shorted or are they low tension?

 

[2informaticos]

Both values look good.

Check the basic voltages/signals from power on sequence.

 

[hgoncalves]

Hi again,

I get

PP5V_S3 =0v

U7201:
5v3v3_reg_en = 3.3V
ppbus_g3h 12.56v
pp5v_s5 = 5v
p5vs3_vbst =4.5v
p5vs3_vfb = 0
p5vs3_entrip = 0V

Do you think that it is U7201? If so, where can I get it in other board model (don't have any other 1286 board)?

 

[2informaticos]

Don't go so fast for 5V_S3.
Do you get 3V3_S5 first?

 

[hgoncalves]

I get 3.3V on P3V3_S5

 

[2informaticos]

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).
If present, check for pulse at PM_SLP_S4_L too.

 

[hgoncalves]

I have a drop pulse at PM_PWRBTN_L but no pulse at PM_SLP_S4_L (steady 0V).

 

[2informaticos]

Then is something related with PCH.
Check PM_BATLOW_L, SMC_ADAPTER_EN and RTC signals.