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A1466 820-00165-A no power on

H

hgoncalves

Active member
Hi,
I have an A1466 820-00165-A that doesn't boot. It has green light (only with original charger) the fan spins, it consumes 250mA on PSU, but don't have any USB activity.

PPBUS_G3H = 8.5V
PP3V42_G3H = 3.4V
PP5V_S0 = 5.0 V
PP3V3_S5 = 3.3V
PP3V3_SUS = 3.3V
PP1V05_SUS = 1.05V
PP1V8_S3 = 1.79V
PP1V2_S5_SMC_VDDC =1.2V
PP3V3_S0 = 0V
PPVCC_S0_CPU = 0V

I notice that C5010, C5017, C5002, C5007 and C5008 had corrosion, so I lifted up all of them, and saw that some pads were burnt. I think that the mac should power on without those caps, but it doesn't. Am I wrong?

Can you help me?
 
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A

Askaleto

Member
Hello hgoncalves,

PP3v3_S0 is missing, but you have PP3v3_S5, first you need to check whether you have P3V3S0_EN. This signal will open load switch U8030 and allow 3.3 S5 to become 3.3V S0. Please have a look at page 59/76 of the schematics and inspect those resistors.

The laptop should boot even without those caps removed, you can add them later and run jumper wires instead of missing pad/trace). Right now, you need to find out what is happening with necessary voltages. On page 62 you have all power rails. the best is to go through all of them and which are missing (
PP3V3_S4, 3v3_S3...)
 
H

hgoncalves

Active member
Hi,

3V3_S0 is not shorted, and i don't have P3V3S0_EN (0V).

I have 3.3V on PM_SLP_S3_R_L (R8178) but 0V on PM_SLP_S3_BUF_L (R8185) witch i think is needed to create P3V3S0_EN, so i think that it may be the U8180. Am I right?.
 
A

Askaleto

Member
If you have 3.3V on R8178 ( M_SLP_S3_R_L ) or on the probe point connected to the pin 1 of U8180 and you have 3.3V on C8180 (connected to pin 5), then you need to change U8180.
 

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A

Askaleto

Member
Then it is possible that this output line is shorted, but if U8180 works OK, then there would be a voltage drop on 3.3V S5 line. Did you check C8186?
When measuring voltage at pin 4, did you also measure on probe test point near R8185? I would remove U8180 and check continuity between pin 4 on the motherboard and resistors R8185(6)
 
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2informaticos

2informaticos

Administrator
Staff member
U8180 has internal pull-up resistor.
So, it should generate 3V on its output directly; check diode mode to ground there.
Also you can remove R8184/85/87, one by one, and see if voltage goes high.
 
H

hgoncalves

Active member
you were right. PM_SLP_S3_BUF_L was shorted and i replaced U3210 (it was getting hot). That short is gone, but now I have 0V on pin 1(PM_SLP_S3_R_L not shorted) and 3.3V on pin 5 of U8180.
I have PP3V42_G3H (3.4V) and R8178 seams to be ok. Can it be Q8131?
 
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2informaticos

2informaticos

Administrator
Staff member
Check for knocked off components.
Possibly aplied heat affected something else on the board.

Which voltages do you get now?
 
H

hgoncalves

Active member
Nothing is out of place.

PPBUS_G3H = 8.5V
PP3V42_G3H = 3.4V
PP1V2_S5_SMC_VDDC =1.2V
PP3V3_S5 = 3.3V
PP5V_S0 = 0 V
PP3V3_SUS = 0V
PP1V05_SUS = 0V
PP1V8_S3 = 0V
PP3V3_S0 = 0V
PPVCC_S0_CPU = 0V
 
2informaticos

2informaticos

Administrator
Staff member
You are missing even PM_SLP_S4_L now; possibly not even PM_SLP_SUS_L.
So check the basic signals from power on sequence.
Start with PCH's RTC signals.
 
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H

hgoncalves

Active member
HI:

PM_SLP_S4_L = 0V
PM_SLP_SUS_L = 0V

PCH_INTRUDER_L = 3.0V
PCH_INTVRMEN = 0.634V
PCH_SRTCRST_L = 0.715V
RTC_RESET_L = 3.29V

PPBUS_G3H = 8.5V
PPBUS_S5_HS_COMPUTING_ISNS = 8.5
PPDCIN_G3H_ISOL = 19.9
PP3V42_G3H = 3.4
PPVRTC_G3H = 3.3
PP5V_S5 = 5V
PP3V3_S5 = 3.3V
PP1V8_S3 = 0V
PP3V3_S4 = 0V
PP3V3_SUS = 0V
PP5V_S4RS3 = 0V
PP5V_S0 = 0V
PP1V2_S3 = 0V
PP1V05_SUS = 0V

Can you help?
 
2informaticos

2informaticos

Administrator
Staff member
"PCH_INTVRMEN = 0.634V
PCH_SRTCRST_L = 0.715V"
I asked that 4 days ago...
How can the board start without correct RTC signals??

Check R1302 and R/C1300.
Possibly bad PCH, or accumulated crap underneath.
 
H

hgoncalves

Active member
Sorry, couldn't work on it...
R1302 and R/C1300. seams to be OK (resistance values are normal).
Do you think it is worth it to do a ultra-sound, or a small reflow on the PCH?
 
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