MacBook Pro Touch Bar 2018 (A1990) - No Boot / No Charge

deann1330

New member
Good afternoon,
Firstly thank you very much Louis for all the brilliant videos you do educating the public, I have spent hours listening to you say PPBUS.

Ok here comes my problem..

I have a MacBook Pro 2018 (A1190) which no longer powers on or charges.

I have a USB Power Meter & when plugging this in I see 19.9v 0.02amp (With the battery removed) When the battery is plugged in I see 19.9v however the amp cycles starting at 0.02 and ending around 0.86 then back to 0.02.

I have had a really good look at the board & it would appear nothing looks suspicious & I can confirm this has no water damage as I have owned it since new. I have taken some readings see below - Any idea.

PPBUS_G3H - 12.61 Volts -
PPBUS_HS_CPU - 12.61 Volts
PPBUS_HS_GPU - 12.61 Volts
PPBUS_HS_OTH5V - 12.61 Volts
PPBUS_HS_3V3G3HRTC_X - 12.61 Volts
PPVCC_S0_CPU - 0 Volts
PPVCCSA_S0_CPU - 0 Volts
PPVCCGT_S0_CPU - 0 Volts
PPVCCIO_S0_CPU - 0 Volts
PP1V2_S3 - 0 Volts
PP1V2_S3_CPUDDR - 0 Volts
PP1V2_S0SW - 0 Volts
PP2V5_S3 - 0 Volts
PP1V05_PRIM - 0 Volts
PP3V3_G3H_T - 3.35 Volts
PP1V8_G3S - 1.8 Volts
PP5V_G3S - 5.14 Volts
PP3V3_G3H_RTC-X - 3.3 Volts
PP3V3_G3S_T - 3.3 Volts
PP3V3_G3S_X - 3.3 Volts
PP3V3_S0SW_TBT_X - 0 Volts

I do notice on the below however when testing for a short to ground I get the below, the rest is fine.

PPBUS_HS_GPU - 12.61 Volts - 0.002 Ohms
PPBUS_HS_OTH5V - 12.61 Volts - 0.002 Ohms

Would this stop the MacBook Pro from powering on or taking a charge?
I did read it could potentially be a faulty CD3215 Chip but my charger is negotiating 19.9v so surely this would not be the case?

Thank you for taking the time to read this & reply.
 
Last edited:

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Rapid question, isn't still your machine under warranty?
If yes, go fast to Apple.

CD3215 dbips are all good, as you get 20V at USB-C ports.

"PPBUS_HS_GPU - 12.61 Volts - 0.002 Ohms "
I can only suppose you checked ohm (or diode scale) under power.
NEVER-EVER do that again!!!

Post 820-xxxxx board code.

You can try to put it in DFU recover mode, just in case.
All necessary info already posted on the forum; use search function.
 

deann1330

New member
First of all, welcome to the forum!

Rapid question, isn't still your machine under warranty?
If yes, go fast to Apple.

CD3215 dbips are all good, as you get 20V at USB-C ports.

"PPBUS_HS_GPU - 12.61 Volts - 0.002 Ohms "
I can only suppose you checked ohm (or diode scale) under power.
NEVER-EVER do that again!!!

Post 820-xxxxx board code.

You can try to put it in DFU recover mode, just in case.
All necessary info already posted on the forum; use search function.
Unfortunately, its no longer covered :(
In terms of checking ohms I had it powered off when checking, my apologies it reads as if I had tested it powered on which is not the case it was just how I formatted my data.

How would I find the board code? I have the schematics for 820-01041 & it looks identical to this board & has helped me find all those rails so I am guessing this could be it?

What is DFU recovery mode? I will search the forums and get back to you on that one, if it needs to power on though I won't be able to do that.

Thanks for the speedy response! :)
 

deann1330

New member
Unfortunately, its no longer covered :(
In terms of checking ohms I had it powered off when checking, my apologies it reads as if I had tested it powered on which is not the case it was just how I formatted my data.

How would I find the board code? I have the schematics for 820-01041 & it looks identical to this board & has helped me find all those rails so I am guessing this could be it?

What is DFU recovery mode? I will search the forums and get back to you on that one, if it needs to power on though I won't be able to do that.

Thanks for the speedy response! :)
Just read about DFU recovery and I did actually try this before I started to take the MacBook apart however I was doing the recovery from a 2015 MacBook Pro which uses a USB-A socket and the 2015 MacBook was complaining about the cable being a Thunderbolt cable (Which it isn't) & would not find the 2018 MacBook through the software.

Looking on the Apple website it does mention you can do this from a USB-A to USB-C Cable (Well... from an "Apple Approved" I may add but fails to tell you which cable this is!)

Few Questions:

1, Has anyone managed to do the DFU Recovery using a USB-A to USB-C Cable?
2, If I was to get another 2018 MacBook to attempt this DFU Recovery (USB-C to USB-C) would I need to put the MacBook back together or should I be Okay doing this with the board our of the chassis?
3, Does those voltages look okay and is the suspect problem pointing to be maybe the T2 Chip?
4, How come I get 0.002ohm resistance on the GPU Rail?
 
Last edited:

2informaticos

Administrator
Staff member
Do NOT quote an entire post visible few centimeters above.
Maintain forum aesthetic, please.

Be aware of multimeter readings.
I'm sure you cannot read 0.002 ohm; that means 2 miliohm!
2 ohms, or 0.002 in diode mode, could be normal value for CPU and GPU core.

No idea if DFU works on board alone, but you can try.
I remember some member complained that recover didn't work with an original Apple cable.
Use the correct (dedicated) USB-C port for DFU.
 

deann1330

New member
Going to see if I can borrow a friend's laptop which has USB-C tomorrow to try this and will report back.
Before I put the board back in the chassis though any last recommendations on what I should check?

Cheers.
 

deann1330

New member
Update.
So interestingly when I attempt to do the DFU restore the host MacBook does see the DFU however when I attempt to restore or revive I get the below error.

Unexpected device state 'DFU' expected 'RestoreOS' [com.apple.MobileDevice.MobileRestore – 0xFAE (4014)]

Anyone else familiar with this error?
 

deann1330

New member
More interesting facts.
With the USB Voltage tester plugged in if I follow the SMC reset process, it reboots the USB Voltage tester so SMC is successfully being reset but still nothing on screen / any sign of life.

I spent the afternoon looking for information about the error I got when attempting to revive DFU so I could potentially update this thread but unfortunately I have not stumbled across anything which may be of use to anyone who may too be suffering from this issue.

will keep you posted.
 
Top