A1502 820-3476-A green light no power on

[nahuelaune]

Hi! I've got this laptop with this problem. It's got green light and after a few seconds it turns orange, the power supply shows a 0.01 Amp. I checked the power aliases and this is what I've got:

-PPBUS_G3H 12.58V
-PPBUS_S5_HS_COMP 12.58V
-PPBUS_S5_H5_OTHER5V 12.58V
-PPBUS_S5_H5_OTHER3V3 12.58V
-PPDCIN_G3H_ISOL 18.27V
-PPDCIN_G3H 18.27V
-PP3V42_G3H 3.44V
-PPVRTC_G3H 3.35V

-PP5V_S5 5V
-PP5V_S4 0V
-PP5V_S0 0V

-PP3V3_S5 3.35V
-PP3V3_S4 3.35V
-PP3V3_SUS 3.35V
-PP3V3_S3 3.35
-PP3V3_S0 0V (SHORT TO GROUND)
-PP3V3_S0_FET 0V (SHORT TO GROUND)

I injected 1.5v into pp3v3_s0 and the only thing I could touch was heating is the GPU. Would appreciate any help.

Also I took out R5080 because I measured it and I think it's also short to ground as I read in some forum.

When I plug the battery the power supply goes up to around 0.7 amp, so I assume it's charging.

Thanks!!

[bluestone]

Re: A1502 820-3476-A green light no power on

with this boards normally PP3v3_s0 is shorted around the sound chip (U6201) so check C6305 and C6306.

Also check impedance on L7630

[nahuelaune]

Re: A1502 820-3476-A green light no power on

Hi bluestone, I'm checking those capacitors. I put the multimeter in 200 ohms and it shows 0.1 ohms in L7630, is it ok? Thanks for your answer!

[nahuelaune]

Re: A1502 820-3476-A green light no power on

I checked all caps around the sound chip and none of them got hot, I injected 3amps and isopropyl alcohol. still get hoy the GPU, as I can feel.

[bluestone]

Re: A1502 820-3476-A green light no power on

I checked all caps around the sound chip and none of them got hot, I injected 3amps and isopropyl alcohol. still get hoy the GPU, as I can feel.

This model does not have a GPU, Check L7630 in diode mode and post.

[nahuelaune]

Re: A1502 820-3476-A green light no power on

Sorry, I thought the little rectangle in the CPU chip was the GPU. checked L7630, beeps... OL in the multimeter.

[nahuelaune]

Re: A1502 820-3476-A green light no power on

Some extra information, I bought this computer to take some parts but I tried to fix it first. Under the keyboard It has something like water damage, it's from the 3.5mm audio jack, ThunderBolt, etc. so maybe it had a liquid damage, I can't see corrosion because probably (90% sure) someone tried to fix it before.
EDIT: in L7630 the multimeter says 0.0.

[nahuelaune]

Re: A1502 820-3476-A green light no power on

I found corrosion in u8005, I took it but the short is still there.

[bluestone]

Re: A1502 820-3476-A green light no power on

Sorry, I thought the little rectangle in the CPU chip was the GPU. checked L7630, beeps... OL in the multimeter.

That's the PCH if it reads 0.00 in diode mode meaning your CPU is fried. Option ow is to replace CPU or replace the whole motherboard

[nahuelaune]

Re: A1502 820-3476-A green light no power on

Ok bluestone, thank you for your time!! Is there any other measurement I could do to be completely sure that the problem is the pch? I mean because of the corrosion and maybe liquid damage.