[HELP]a1990 820-01041 NOBOOT, STRANGE!

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

i've discovered something

if i connect the upper left or right port to my mac m1, i receive the message

"impossible to use accessory"

if i try to connect the others two ports, nothing happen

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

is it a problem if i have used my macbook air 30w power supply to do all tests?

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

used 100w power supply, no luck

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

xa/xb/ta/tb cc1 0v
xa/xb/ta/tb cc2 1,5v

SMC_RST, if it is TP_CHGR_SMC_RST_L, i have 1,7 and not 3v

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

3,3 on l6960 and 7660

0v on r6941 (UPC_PMU_RESET)

l7821/22 0v
l7817 0,8
l7816 0,8
l7815 1v
l7814 1v
l7813 1,7
l7806 0,7
l7810 0,8
l7811 0,8
l7812 0,8

l7410 and l7420 i have 0,2ohm and 0,002 in diode mode

l9080/580 seems fine

tried to force dfu mode with a wire with no luck

remember you what i 've discovered some post ago:

"
if i connect the upper left or right port to my mac m1, i receive the message

"impossible to use accessory"

if i try to connect the others two ports, nothing happen

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

i have changed with brand new chip, All 4 cd3215

One port now can switch to 20v and i think that the notebook boot


so what's next?

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

U3100 is the chip that switch to 20v

According to This usb type c tester, i’ve discovered that on the ports that doesn’t switch to 20v, i have wrong value on pin 6/7/18…All 3 ports, same wrong value on same pins

You can see the values on the port that switch to 20v

https://ibb.co/gSqW21y

https://ibb.co/LR9xj0S

this pins are (i think) d+ / d- and corrispond to pin usb top N /top P bot N / bot p on motherboard...

those pins goes directly under each cd3215....except for the port that works....in this case they go to usb3000 and then under cd3215...so i think it's because of this that values are different

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

i'm at this point...

https://streamable.com/z9mcly

all ldo presents on each cd3215

[UngaBungaMacbook]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

@phantomEVO I am 70% sure it is one of the CD32.... chip issue probably the side where you have no voltage at all, other 30% would say u3000 is burnt a bit or damaged, that also makes macbook 5v in every port. if you have thermal cam, one of the chips should be hot

[phantomEVO]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

i have 5v on 3 ports, 20v on one port....

[UngaBungaMacbook]

Re: [HELP]a1990 820-01041 NOBOOT, STRANGE!

then swap out 3 of the cd32 chips, I use donor boards for chips. I have repaired over 2k macbooks by now. it might happen, usually i have cd32 problems because people are using low quality usb-c cables that are very loose.