820-00850 - 5v / 0,25a

[Palhano]

Board had a short on the CB308, the UB300 a little burned. I replaced both, but the problem remains.

PPBUS_G3H - 12.3v
3v3_G3H_RTC - 3.3v

I have no voltages on the AWAKE and SLPS2R lines of the U7800.

It is recognized in DFU mode, I tried to revive and restore, both give errors.

 

[Palhano]

LDO lines in diode mode. All the same.

1.8 - 0.470
3v3 - 0.496
1.1 - 0.510
1.8 - 0.511

 

[2informaticos]

All ports have the same behavior?
Do you get 1V1 LDO on every CD3215 chip?

 

[Palhano]

Yes, all ports behave the same.

I have 1.1v on all CD3215's. This line only has voltage on the connected port, correct?

 

[2informaticos]

None of the coils around U7800 has voltage?

 

[Palhano]

Strange, I went to measure, now I have tension.

PP1V1_SLPS2R : 1.1 Volt
PP1V8_SLPS2R : 1.8 Volt
PP0V8_SLPS2R : 0.7 Volt
PP1V2_AWAKE : 1.1 Volt
PP3V3_AWAKE : 3.3 Volt

 

[2informaticos]

Yeah, it shouldn't enter to DFU without these voltages.
I just wanted to confirm actual state.

What error do you get in DFU?
Any SSD, or G3S voltage tries to appear?

 

[Palhano]

In DFU it stays a long time on "Installing system" and then the error:
Gave up waiting for device to transition from
DFU state to DFU state.
[com.apple.MobileDevice.MobileRestore -
OxFCA (4042)]

I have no voltage on SSD, PP1V8_SSD and PP0V9_SSD!

nothing on the G3S 3.3v and 1.8v line.

 

[2informaticos]

Be sure no short on any SSD, or G3S power rail.
I had a case when these voltages come on after several failed DFU attempts.

 

[Palhano]

There are no shorts.

I will try to restore in DFU again.

 

[Palhano]

I bought the S-UEM2 device and decided to go back to work on that abandoned mac.

It showed changes in some pins of the UB300 (31, 33, 40, 42), as it had already been changed, I tried to change it again.

 

[Palhano]

I connected the cable the wrong way. It didn't report any failures.

 

[2informaticos]

Reflash SoC ROM and try DFU again.
Don't forget to make backup first.