Mac A1502 main 820-3476a no video

[reset1986]

hello everyone, I have this motherboard that does not give an image, black screen,
the mac turns on, charges the battery, but it does not ring and remains with black with an absorption from 0.85A 16.5v

I flashed the bios chip, smc and CPU reflow but the situation remains unchanged
there is no liquid damage and the main lines supply power

Do you have any suggestions?

[mon2]

Re: Mac A1502 main 820-3476a no video

Post the voltage of PPBUS_G3H.

Does the CAPS key led toggle after boot?

Do you see any graphics on the lcd with a flashlight?

Reflow of the CPU is risky without a proper bga rework station.

See:
https://repair.wiki/w/A1502_2013-201...ook_Pro_Retina

[reset1986]

Re: Mac A1502 main 820-3476a no video

Post the voltage of PPBUS_G3H.

Does the CAPS key led toggle after boot?

Do you see any graphics on the lcd with a flashlight?

Reflow of the CPU is risky without a proper bga rework station.
yes i have a professional bga machine from honton,
I have the 3.3v the machine turns on, the fan runs, there is no activity on the CAPS key, external screen not working,
it is a classic defect of gpu, can I measure some signal in particular?

See:
https://repair.wiki/w/A1502_2013-201...ook_Pro_Retina

yes i have a professional bga machine from honton,
I have the 3.3v the machine turns on, the fan runs, there is no activity on the CAPS key, external screen not working,
it is a classic defect of gpu, can I measure some signal in particular?
Thanks

[reset1986]

Re: Mac A1502 main 820-3476a no video

I performed a reballing on the CPU, but the situation does not change, ignition and black, no CAPS key activity, absorption 16.5V 0.85A,
I wanted to ask if they were the rams I could hear the beeps on ignition?
Thanks

Post the voltage of PPBUS_G3H.

Does the CAPS key led toggle after boot?

Do you see any graphics on the lcd with a flashlight?

Reflow of the CPU is risky without a proper bga rework station.



I performed a reballing on the CPU, but the situation does not change, ignition and black screen, no CAPS key activity, absorption 16.5V 0.85A,
I wanted to ask if they were the rams I could hear the beeps on ignition?
See:
https://repair.wiki/w/A1502_2013-201...ook_Pro_Retina

[dellxps15]

Re: Mac A1502 main 820-3476a no video

i have just repaired one 820-3476 today.
1° never reflow things if not needed
2° without battery, when fan start spinning do you have magsafe light turning green then orange?
3° cpu voltages on coil present ? pch core ? report volts here
4° jtag connector already removed ?
5° tried with pram reset ?
6° try with external monitor and usb osx image on usb slot.
7° if board is outside case whatchout from inserting display port correctly otherwise ull burn dcin.
8° keep in mind that that lcd if no backlight is very dark and really hard to see if it's a backlight issue if u dont have a powerfull light to see it.
9° report omh on cpu coils (black on gnd) and red on cpu coil or white resistor near cpu it should be around 170ohm