MacBook 12" 2016 820-00244 not power on

[waterchill]

Good day friends, so I have here this MacBook which is drawing 20V 180mA only the Mainboard and 1,4A with battery. No Apple logo no boot. Here are some voltages:

PPBUS_G3H = 8,70V
PP3V3_G3H = 3,30V
PPDCIN_G3H = 19,7V
PP3V3R3V0_AON = 3,3V
PP5V_G3H = 5,1V
PP5V_S4 = 5,1V
PP5V_S0 = 5,1
PP3V3_S5 = 3,3V
PP3V3_SUS = 3,3 V
PP3V3_S4 = 3,3 V
PP3V3_S0 = 3,3V
PP1V8_SUS = 1,8V
PP1V8_S3 = 1,8V
PP1V5_S0 = 1,5V

I found out that PPVCORE_S0_CPU = 0V / 10,5ohms. Checked this with a 2017er MacBook resistance is same but 0,635V. So I have checked:

VCIN of U7210 and U7230 = 5,10V
VIN of U7210 and U7230 = 8,70V

ZCD_EN = 0V = CPUCORE_FCCM

CPUCORE_FCCM is produced by U7100

VIN of U7100 = 8,7V
VCC of U7100 = 5,1V

I don't see an enable pin for U7100. Schematics says for VIN 12,9V I got 8,7V, maybe this is problem or bad U7100? Or something else?

cheers

 

[2informaticos]

"PPBUS_G3H = 8,70V"
Was that with battery connected?
You should check with charger alone.

Any history fault available?
You can try known good BIOS; just make backup first.

 

[waterchill]

"PPBUS_G3H = 8,70V" = without battery only the board alone. Unfortunately there is no history available With battery connected around 8,4V

 

[waterchill]

Is the U6100 chip the bios on this board?

 

[2informaticos]

Yes, that is.

 

[waterchill]

Look like the bios chip is dead. Pls can you confirm that this is the right direction to solder on the board of the ubos2? Anyway I reballed several times and tried both directions but no reaction of the chip.

 

[2informaticos]

The marked corner on chip and adapter board seems to correspond in the picture.

 

[waterchill]

ok thank you. I will order a new chip and try again

 

[waterchill]

I have now replaced the SPI Rom, it's not an quick job, because you have to solder and reball after programming. Noticed that there are 2 kinds of chips. Didn't got the original one, but it is possible to turn the chip 90° and it is ok. So now the situation is, that I got no voltages. The only voltage I get is the PPDCIN 5V 3mA. Looks like Q3100 or U3100 is faulty, but why now? This board is driving me crazy...

Q3100:
Gate 1= 10,80V
Gate 2 = 6,90V

I do not understand why the gate have more voltage that the incoming voltage?

 

[2informaticos]

CD3215 chip has internal charge pump to control the Gate for N-channel MOSFETs.

Did you solder the chip in the same orientation like it was in MLB?
Did you verify the file after writing?

 

[waterchill]

Not possible to solder in same orientation because the chip is little bit different. I have to rotate the chip by 90 degrees. File is double checked

 

[2informaticos]

Did you compare datasheet of both chips?

 

[waterchill]

Schematics says Q64FVBYIQ this chip here is Q64FVYIQ this is looks the same. Also Alixpress sales this as the same. This chip I bought 5pcs was sold as the rom for A1534. What I have tried now is multiple times changed the chip, erased sold again, nothing changed. Also tried power without this chip, same behaviour. I don't how is the behaviour of a mainboard without the rom, but I think it should also without the rom switch to 20V or not?

 

[2informaticos]

If BIOS didn't help, then you have bad CPU.
It fails a lot on A1534, as no fan used.

 

[waterchill]

I have ordered now a new bios original programmed bios chip. Will also change the U3100 and the Q3100