Macbook Pro A1989 - 820-00850 A no boot

[obelix24]

Hello All,

I'm working on one Macbook Pro 13" A1989 board number 820-00850 A and i'm out of clue

When i connect board with battery, keyboard, display, ... (everything) i'm getting 20V and current goes from 0.6A to 1.9A - it stays on 1.9A but nothing no chime, no apple logo, but i can click trackpad (as i know this means that T2 is ok)

When i connect only board (everything disconnected) it's taking only 5V (on all usb-c) and 0.16A or 0.36A (it's just jumping to 2 values, doesn't stay on any)

I've checked
PPBUS_G3H - 12.3V
PP3V3_G3H - 3.3V
PP3V3_S5 - 0V

I've connected to another mac and i was able to put it to DFU and start restore it finished with no error but not apple logo or chime.

what i've done
I've replaced UB400 but there is one ripped pad - NC_USBC_TB_RESET_L but i was not able to recreate it as there is no trace so probably NC pad. I've tried 3 UB400 chips and still the same issue (only 5V when battery is not connected)

Any idea what should be checked next ?

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

I've just checked when i connect power to each USB-C i get 1.1V only on XA and XB

PP1V1_UPC_XA_LDO_BMC - 1.1V
PP1V1_UPC_XB_LDO_BMC - 1.1V
PP1V1_UPC_TA_LDO_BMC - 0V
PP1V1_UPC_TB_LDO_BMC - 0V

When i check in diode mode :
PP1V1_UPC_TA_LDO_BMC - OL
PP1V1_UPC_TB_LDO_BMC - 0.512

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

The LDO rail to power the BMC interface will only be active for the port used to power the logic board.

Move the power adapter to the other USB-C port and confirm if the BMC LDO rail is then 1v1.

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

yes I know I've tested all test point for all 4 ports (I've also turned the cable on each port).

does this mean that CD3215 needs to be changed and maybe it's faulty ?

If yes can I use CD3215C00 (original on board was CD3215C00Z)

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

You are getting 20v so the ace controllers are working. If you are stuck at 5v then these power delivery controllers could be at fault.

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

yes i'm getting 20v but only when battery and other stuff is connected.

if i connect only board itself to power it takes only 5v. So do you think i have to replace CD3215 ? can i use CD3215C00 or i have to use only CD3215C00Z

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

There are some models that require a working battery to boot even if using an external power adapter.

Not sure if this is one of those models.

On the ACE controller, check the website from Rossman. Often he posts the compatibility list. You should also ping suhms store on AliExpress to confirm. Then update this thread.

On our many back end projects is a break out board to experiment with this ace controller. Started another one for the isl9240 but our building / my lab was destroyed by a drunk driver. Now each project is delayed.

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

This website lists them to be different:

https://www.diyfixtool.com/products/...42357993177317

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

Best to source the original and from reliable vendors:

https://www.masterliuonline.com/prod...riantsId=10139

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

There are some models that require a working battery to boot even if using an external power adapter.

Not sure if this is one of those models.

On the ACE controller, check the website from Rossman. Often he posts the compatibility list. You should also ping suhms store on AliExpress to confirm. Then update this thread.

On our many back end projects is a break out board to experiment with this ace controller. Started another one for the isl9240 but our building / my lab was destroyed by a drunk driver. Now each project is delayed.

What do you mean by ACE controller ?

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

Ace controller is the nickname of the cd321* devices from Texas Instruments.

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

ok so I replaced both CD3215C00Z with CD3215C00, now the board is taking 5V and then switch to 20V.

I've tried to revive and also restore in DFU mode but I'm still ending just with padlock.

There is no error message in Apple Configurator 2 (I don't know where should I search for log from this app)

[mon2]

Re: Macbook Pro A1989 - 820-00850 A no boot

Nice!!
https://discussions.apple.com/thread/253277152

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

this doesn't help as i have nothing on the screen where to put password.
Padlock is shown on the macbook where i started apple configurator.

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

I've checked PP1V8_SSD and PP0V9_SSD both ok (1,8V and 0,9V)
Also I've checked
PPVDDCPU_AWAKE - 0,54V - I've checked on L7806 - according to schematics it should be 0,625V - 1,06V
PPVDDCPUSRAM_AWAKE - 0,8V

it looks like everything I'm checking is ok but not working. Enters DFU ok, restore with no error (it just stays long time in Installing system and then there is only padlock in Apple Configurator.) Anyone any idea ?

I was just randomly checking and on test point near T2 PP4V7_SE_TVDD I have only 2,49V but it should be 4,7V

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

I'm curious to reflash SOC ROM. But don't know if there is any ROM i can download to replace old one.

and also i have only EEPROM programmer something like this if it will work also ...

[apos]

Re: Macbook Pro A1989 - 820-00850 A no boot

Hello,you may need U-BOS2 to flash bios .

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

is it not possible to do it some DIY way ? as don't need such expensive tool for 1 usage only

[obelix24]

Re: Macbook Pro A1989 - 820-00850 A no boot

OK i was able to flash bios on original SOC ROM IC using my EEPROM programmer i have to be little bit creative and solder some small wires ... I've used AsProgrammer. I've tried 2 bios files that i've found online but i'm still getting error on line 500 or 600 ... but anyway i've tried to put the IC back and still exactly the same problem. I'm able to put macbook to DFU but when i try REVIVE or RESTORE i'm ending at Installing System (the bar goes under S (System) it's approx 50% and it stays there for few minutes and the i got only Padlock ...

[pedribor]

hi obelix24
I have the same problem. Could you solve it?