820-3332-A | Amber light, 5V issue, no chime, no boot, fans start spinning twice, then stop.

[2informaticos]

First of all, welcome to the forum!

Remove CPU/GPU heatsink when you need to apply heat in the near area.

Video artifacts and machine stuck on progress bar can be caused by bad GPU.
Bad battery can cause this too.

You should disable GPU now and check if board stays on.
First check resistance to ground on GPU coils.

 

[stef4n]

First of all, welcome to the forum!

Remove CPU/GPU heatsink when you need to apply heat in the near area.

Video artifacts and machine stuck on progress bar can be caused by bad GPU.
Bad battery can cause this too.

You should disable GPU now and check if board stays on.
First check resistance to ground on GPU coils.

Hi 2informaticos. Thanks for the swift answer and the welcome.

Regarding the artefacts and boot issues, I had tested with/without trackpad, with/without battery, and with/without a new battery. It never changed anything. But I suggest we ignore all of this for the time being, since it's likely not correlated to the current no-boot-at-all situation.

Prior to start disabling the GPU, I checked the resistance to ground on "GPU coils"; I assumed you referred to the below list:
L8930: 27 Ohms
L8960: 27 Ohms
L7560: 1.2 Ohms
L7550: 1.2 Ohms
L7510: 1.1 Ohms
L7520: 1.0 Ohm
L7530: 1.0 Ohm
Diode mode => bip =>short

L7630: 13 Ohms,
Diode mode => bip => short
if plugged: PPCPUVCCIO_S0_REG_R shows 0V for ~4sec, then 0.3, 0.5, 0.7, 1.08, and back to 0V

L7100: 8 Ohms
Diode mode => bip => short

U7100 shows 0V on pin 5,6 and 15 (PVCCSA_EN); result on pin 15 is not suprising given PM_SLP_S3_L

PP5V_S0_CPUIMVP, on pin 1 C7401 shows 0.3V...3.8V...

And I'm back on the page presenting the Mobile System Power State Table, the S5 Rail Enables & PGOOD, S0 Rail PGOOD Circuitry

 

[2informaticos]

Beep is not same with short!
Multimeters beep until 0.050-0.075 (diode mode), depending on the model.
That's the reason I asked ohm resistance, not diode mode, on the mentioned coils.
Always switch to ohm scale, for low diode mode values; usually under 0.005 readings.

The resistance on mentioned coils look good, in this case.
Try to compare with working board, if possible.

L7630 pulsing to 1.08V is good sign.
Check for pulse on the other big coils.
Try to start in SMC bypass.

PPBUS_G3H and 3V3_S5 voltages are stable?

BTW, write directly into reply box, instead of clicking Reply button.
Unless you have a real reason to quote an entire post, visible few centimeters above.
Please, maintain forum esthetic.

 

[stef4n]

Indeed, beep not equal short, sorry.

Will try to find a working board tomorrow evening. Will also try to boot in SMC bypass. I will update this thread after.

Regarding 3V3_S5, I measured it on R7832 pin 1, C7831 pin 1, Q7830 pin 1,2,3, and R7812 and C7811 pin 1, I systematically get a stable 3.36V
Regarding PPBUS_G3H, it is also perfectly stable at 12.66V. I measured it on pin 2 of F7040 and F7041, R6905, Q5300, etc.

About the coils:

L8930: 0.000 V, not pulsing
L8960: 0.000 V, not pulsing
L7560: 0.000 V, not pulsing
L7550: 0.000 V, not pulsing
L7510: 0.000 V, not pulsing
L7520: 0.000 V, not pulsing
L7530: 0.000 V, not pulsing

L7100: pulsing, 0.000V for 4 sec, then jumps quickly to 0.20 and 0.806V. Then back to zero
L7630: pulsing, 0.000V for 4 sec, then jumps quickly to 0.70 and 0.557V. Then back to zero

L8360: not pulsing, stable and constant 0.000V
L8310: 0.000V for 4 sec then 0.4 [mV], 0.3 mV, 0.2mV, back to 0 for 4 sec
L7720: 1.829V...1.736V, 1.5 V, then 0V for 3-4sec

L3895: slightly fluctuating: 0.417 to 0.429 V
L7030: slightly fluctuating: 12.90 to 13.24V
L7330: pulsing: 1.3V, 1.1V then 0V for 3-4 sec
L9830: pulsing: 0.8V, 0.3V, then 0V for 3-4sec