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MacBook Air 2017 820-00165 - green/amber light, no boot - PPBUS_G3H ok, PPDCIN_G3H 16.42V, PP5V_S0 5.08V, PPVCC_S0_CPU 0V, PP1V05_S0 0.84V [Fixed]

S

stef4n

Member
Hello,
I have a MacBook Air that suddenly stopped working while I was reinstalling the OS. No prior work on the logic board.

PPBUS_G3H: 8.58V
PPBUS_S5_HS_COMPUTING_INS: 8.58V
PPBUS_S5_HS_OTHER_ISNS: 8.58V
PPDCIN_G3H: 16.42V

PP5V_S0: 5.08V
PP3V3_S0: 3.304V
PP3V3_S5: 3.304V (as I have S0, useless measure)

PP1V05_SUS 1.05V
PP1V05_S0 is 0.84V

PPVCC_S0_CPU: 0V
Checked L7310 & L7320: 0V

Referring to schematics P52/76, I also checked:
CPUVR_PWM1: 5.5mV
CPUVR_PWM2: 20mV
CPUVR_FCCM: 2.34V

Plus:
Q7310:
8.58V on pin 5 -> OK
0 to 40mV on pins 1 to 3
Q7311: 0V

Q7320: 8.58 on pin 5 -> OK
0 mV on pin 1-3, 80mV on pin4 but could be multimeter noise
Q7321: 0V, but if I move my probe from pin 5 to 8, (assuming 8 is on the opposite site of 1), then I read 300mV to 1.08V then back to 100mV a lot

R7311: 4.77V
R7321: 4.77V

On U7200, CPU_VR_EN is 0V, but that should come from the CPU, which is obviously not powered
CPU_VR_READY is 0V

Shall I try to remove Q7321, then see what happens, then Q7311 ?

(I read this post:

820-00165-A no power

No pulse at all? Did you check at exact time when trigger SMC_ONOFF_L? "SMC Bypass I don't know how to do it" https://boards.rossmanngroup.com/threads/how-to-collection.60974/ Google also knows...
boards.rossmanngroup.com boards.rossmanngroup.com
 
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S

stef4n

Member
Good evening 2informaticos,
0.078V on pin 1 of C7278,
0.078V on pin 1 of R7280
0.078V on pin 1 of R7279
0.078V on pin 1 of R1931
(Black probe on ground)

And indeed, it looks like I should have had 1.05V there according to https://openboarddata.org/?a=showboardsolutions&bpath=laptops/apple/820-00165)

CPU_VCCST_PWRGD is at 1.5mV i/o 0.53V
ALL_SYS_PWRGD is at 60mV i/o 3.3V

(I'm currently on around U8160 p 59/76, updating this post live)
PP3V3_S0: 3.300V on C5540, pin 1
P5V_DIV_VMON oscillating 150-360mV
P1V5_DIV_VMON osc. 150-250mV
PP5V_S0 on test pad close to R1845, pin 1: osci from 200mV to 1.xx V, multimeter moves too fast to read
This contrasts with above measurements. I checked again on L7750, PP5V_S0 is at 5.08V

On pad 2 of U8160, there is 3.3V (there is no U8160 on that board though)
On pad 3 (P5V_DIV_VMON),oscillating, 200mV to 2.8V
On pad 5 (P1V5_DIV_VMON), osc 150-380mV 0L
On pad 6 (P1V05_DIV_VMON), osc 150-300mV

R8151 pin 1: 5.08V
R8158 pin 1: 3.3V
R8155 pin 1: 0.74V

gosh...
C7630 is corroded

CorrodedC7630.png
 
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2informaticos

2informaticos

Administrator
Staff member
"Black probe on ground"
That way is rarely used for diode mode readings.
Anyway, has to always check with red probe at ground first.

Replace C7630, is the boost capacitor.
Be sure R7630 is good, as traces too.
 
S

stef4n

Member
"That way is rarely used for diode mode readings."
What is the correct way ?

C7630 replaced, other cap and traces were OK
Fixed ! MacBook Air alive :)
Thanks 2informaticos for the direction
 
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