820-00840 no boot!! A BIG MISTERY

[phantomEVO]

according to openboard data

l7900 should be 290 and i have 150 (resistence 150ohm)
l8060 should be 260 and i have 180 (resistence 190ohm)

[phantomEVO]

in smc bypass i have apple logo with bar loading, then error. this process is in loop

[mon2]

Which error? What is connected during this boot process?

[phantomEVO]

"YOUR COMPUTER RESTAR BECAUSE OF A PROBLEM" PRESS A KEY OR WAIT A FEW SECONDS TO CONTINUE STARTING UP.

all things connected

[mon2]

Try to boot in safe mode or internet boot.

Sounds like a software fault:

https://support.apple.com/en-ca/102382

[phantomEVO]

like i said, i can boot only in bypass mode. in this mode, i can't arrive to desktop...i have the loading bar with apple logo, then when it's starting os, the logo disappears and i have the error (even disconnecting everything)

simply press power button doesn't do anything

[mon2]

Your OS sounds to be corrupt. This is a software fault from the shared details. Boot from the internet. Report your status from that mode of boot.

[phantomEVO]

how can i boot from the internet if the notebook is totally dead???? it doesn't respond to any key unless i boot in smc bypass...like i have already said, if i push the power button, nothing happen

[phantomEVO]

ps the apple logo has an half darker then the other

i repeat: I HAVE NO CHIME IN SMC BYPASS: COULD IT BE IMPORTANT?

[phantomEVO]

LID_OPEN and SMC_LID_LEFT are 3,4v;

smc_lid_right 0,4 this line is ok in resistence and diode mode

replaced u5255 no luck



, all tracks are ok

[phantomEVO]

i've Removed R5257 and joined pins 1 & 2 of U5255....still same problem

[phantomEVO]

its' like something is missing or not correct...i'm going crazy! please help!

[mon2]

ps the apple logo has an half darker then the other

Sounds like a local display backlight fault. Test with an external display over USB Type C dongle to HDMI.

[phantomEVO]

edit

[phantomEVO]

I'm going crazy.

I wonder why trigger button don't work at all. Maybe because of a Dead battery?

And what the hell happen as soon as the os is booting????? Something that miss

[mon2]

Trigger button = on/off button?

See attached. Locate the shorting PCB pads that are present on all macbook models. One pair of pads on one side of the board; another pair of pads on the other side.

In the absence of a keyboard, you can use metal tweezers to emulate the power button. If you (carefully) use tweezers on these pcb pads, can you power the board on/off?

Have you tested with an external screen as per suggesting in post #33? What was the result?

[phantomEVO]

yes trigger button is working....but i cant try to boot with battery only, because it is dead. i've ordered another one just in case.

i can't see anything on external monitor.

this is a small recap of the problem

https://www.youtube.com/watch?v=k19kir4aAWE


0

[phantomEVO]

i have even pp5v_s0 (that goes to 0)......so why it doesn't boot!!

[phantomEVO]

help....

[mon2]

Have you attempted with a known good bios?

https://www.badcaps.net/forum/troubl...e2#post3540281
* see post # 30

You have a lot working on this unit - including video so the bios is not likely to be the fault.

Have you attempted to boot from internet?


To boot an A1708 (a MacBook Pro model) from the internet into macOS Recovery, press and hold the Option (Alt) + Command + R keys immediately after turning on the computer.
Here's a more detailed explanation:

• Shut down your Mac:
  Ensure your MacBook Pro is completely shut down.
• Turn it on and press the keys:
  Press the power button to start the Mac, then immediately press and hold the Option (Alt) + Command + R keys.
• Wait for the Recovery screen:
  Continue holding the keys until you see the macOS Recovery screen, which will prompt you to connect to the internet.
• Connect to Wi-Fi:
  If you are not already connected to a Wi-Fi network, you will need to connect to one from the Recovery screen.