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A2289 - 820-01987 5V

M

mushr00m

Member
Went to a friend lab and found what I think is the culprit

I got a video if you want of the thermal camera.

U3701 is getting hot and it actually have some variations of PP1V8_G3S and PP3V3_G3S underneath it.

To be honest with you it start getting hot from the corner around R3702 and R3705

I went to measure these component

WLAN_SROM_STRAP = 0.003V
WLAN_SROM_SIZE = 0.004V

Also I am not sure remove this component from the board and if it's a component that I can replace? I don't think I have another one. Also are they a component that needs to be programmed in order to function?
 
2informaticos

2informaticos

Administrator
Staff member
MLB should turn on without U3701.

If you want to change WiFi chip, need donor board and transplant also U3710/50.
 
M

mushr00m

Member
Got it

But the main question is.

Should I remove this component for the short to be gone

OR

It could be the same as U8200 we are removing someone that is not the culprit and should search more to find the real one?

Isn't it smarter to take a look around... maybe could be a cap attached to it? I am not sure.

What's your toughts about it?
 
M

mushr00m

Member
Removed U3701 and now we have the following on diode mode

PP1V8_G3S = 0.285
PP3V3_G3S = 0.371

Which I think is perfect according to your openBoardData.

Now what would be next steps put back the components which I remove and turn the board ON without this WIFI module since I do not have a donor board?

I went to Aliexpress and didn't find any donor board to buy and also didn't find the wifi IC to sell by itself =/
 
M

mushr00m

Member
Put everything back on the board apart of U3701

Plugged the amp meter on the USB-C so we have 20V

Went to assemble the board on the case

Now we still have 20V powering the board but the fan is spinning at full. I only did not connected the battery and no image on the screen
 
M

mushr00m

Member
Plugged the board and did the same behavior

Fan at full speed
No boot/apple logo
Its getting 20V on the charger

Removed the charger still fan spin

Had to hold power to turn it off
 
M

mushr00m

Member
I went to measure these ones.

Let me know if there is another that you still need

PPVCC_S0_CPU = 0v
PPVCCEDRAM_S0_CPU = 0v
PPVCCIO_S0_CPU = 0V
PPVCCSA_S0_CPU = 0V
CPUCORE_ISNS1_P = 0V
CPUCORE_ISNS2_P = 0V
CPUCORE_ISNS1_N = 0V
CPUCORE_ISNS2_N = 0v
 
2informaticos

2informaticos

Administrator
Staff member
Why checking so many CPU core lines?

VCCIO should appear first; so no way to get core voltage.
L8100 gets voltage?

You should try DFU...
 
2informaticos

2informaticos

Administrator
Staff member
Try only DFU revive, if you don't want to erase the data.
The data may be lost anyway, if any NAND is damaged...
 
M

mushr00m

Member
Tried DFU with external switch and also nothing happened.

On the apple 2 configurator it gets a message - Cannot use thunderbolt accessory
 
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M

mushr00m

Member
Yes my friend

I am using the original cable USB-C

One to connect between the 2 macs
One to connect the default mac to the MagSafe

What's wrong with this message?

Also these mac do not even thunderbolt port. Why are you talking this?
 
M

mushr00m

Member
By the way I went to measure the voltage of PP3V3_G3S and PP1V8_G3S


Before assembling the board on the case diode mode was according to openboardata

But now after these DFU tries I went to measure voltage

PP3V3_G3S = 3.3
PP1V8_G3S = 0V and in DIODE MODE = 0.003

So there still a short on PP1V8_G3S **** with it on the macbook case with everything connected

PS2 = Just removed the board from the case and outside the case there is not short on PP1V8_G3S.


OMG What the hell is wrong with it

What should I do after this finding?
 
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