A1502 820-4924-A no power

[hgoncalves]

Hi,
I have an A1502 820-4924-A that has green light, but no fanspin and no power.

PP5V_S4 and PP3V3_S4 are missing.
PM_SLP_S4_L is missing and R1461 is OK
PM_BATLOW_L = 3.3V
SMC_ONOFF_L = 3.4V

PCH_INTRUDER_L = 2,7V
PCH_INTVRMEN=3.1V
PCH_SRTCRST_L= 3.3V
RTC_RESET_L=3.3V

Can you help?

 

[2informaticos]

Fan will start very late on this model; not before CPU gets really hot.

Do you get 3V3_SUS?

 

[hgoncalves]

Hi,
Yes, I have 3.3 on PP3V3_SUS

 

[2informaticos]

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.

 

[hgoncalves]

I do have a drop pulse on PM_PWRBTN_L

 

[2informaticos]

Check for pulse at PM_SLP_S4_L at same time.

 

[hgoncalves]

PM_SLP_S4_L is 0V but i have a small pulse when i triger SMC_ONOFF_L

 

[2informaticos]

Check the same for PM_SLP_S3_L and all big coils.

Just in case, try starting in SMC bypass mode.
Be sure to have original 60/85W Magsafe 2 charger.

 

[hgoncalves]

Hi,
I Have a pulse on PM_SLP_S3_L but no pulse big coils when triger SMC_ONOFF_L, and on SMC bypass mode nothing happends.
With an original charger, the result is the same, no power

 

[2informaticos]

Trigger SMC_ONOFF_L repeatedly and check for pulse at each coil.
If no voltage pulse at big coils, then check diode mode.
Start checking L7520.

 

[hgoncalves]

Hi,
No pulse on coils

L7520 = 0.420V
L7130= 0.154V
L7560 = 0.153V
L7710 = 0.901V
L3095 = 0.534V
L7430 = 0.145V

L7320 = 0.0003V
L7310 = 0.0004V

 

[2informaticos]

Post U7501 voltages; 23, 12, 13, 22, 29, 21.
Check for pulse at pin 4, when trigger SMC_ONOFF_L.
Use surrounding components as test points, not directly chip pins.

 

[hgoncalves]

Hi,

U7501:
23=12.59V
12=3.4V
13=1.9V
22=3.3V
29=5V
21=3.4V

I think that P5VP3V3_VREF2 is low

I've got no pulse on pin 4 of U7501 when trigering SMC_ONOFF_L.

 

[2informaticos]

If PM_SLP_S4_L pulses, P5VS3_EN should pulse too.
If not, check R8175/79.

"I think that P5VP3V3_VREF2 is low"
VREF2 means something, don't you think?

 

[hgoncalves]

Well, i've never thinked about that, but now that you mentioned, i think that this means Reference Value. Is that correct?

 

[2informaticos]

2V internal reference, to be more precisely; so is good in your case.

 

[hgoncalves]

Tks, for the explanation about VREF.

I do have a pulse on pin 4 of U7501 when Trigering SMC_ONOFF_L. Sorry, I was trigering on the wrong place...

 

[2informaticos]

Then you should have pulse at L7520 too.
If not, there is a problem in U7501 5V area.
Check all resistors and traces.

 

[hgoncalves]

Sorry, the same error. Trigering oat the wrong place.

I do have a pulse on L7520.
The only one that seams to don't pulse is L3095

 

[2informaticos]

That coil is not important.
So you get pulse on other big coils, including CPU ones?