MacBook A2289 820-01987

[Zparts01]

I have a problem I'm hoping someone can help me with. I have an A2289 MacBook that had some liquid damage. After repairing any areas that had corrosion, I was able to get it to show 20v but only .01a on the multimeter. It was consistent on all ports, however I could not get the MacBook to go into DFU mode. I read that I should refllash U4770 and after grabbing the bin from this site I did just that. After soldering the chip back on the board, now I have DFU mode, but the thing is, it won't revive or restore, giving me the error that the device left the DFU state or something to that effect. The strange part is that I do notice the DFU screen in Apple Configurator very briefly indicates something has reset just before it fails, but then goes straight back to showing DFU mode again. It's like it won't come out of DFU now or something. Any idea what the problem could be? Also, the battery of this MacBook is an unknown status. Is it possible that a bad battery could be the cause of the issue or can DFU restore be completed with a bad battery?

[mon2]

Fault may be with the SMBUS lines linked to the battery. Carefully measure the voltage to ground of each pin on the battery pack. Of particular interest are the SMBUS SCL and SDA lines. If either is shunted to ground, this will halt all SMBUS / I2C communications with the host and is a deal breaker for the boot process.

[Zparts01]

They are both reading 3.28v with the battery connected and the MacBook plugged in. Should that be 3.3v?

[Zparts01]

I once again removed U4770 and erased the chip, then put it back on the board. Still stuck in DFU. As soon as I plug it in, it goes to DFU and won't exit DFU mode even when I try to revive or restore. I've looked around and can't find any into to help with this. Seems like most people either have problems getting it into DFU or revive or restore just fails. My problem is that it always goes back into DFU on its own after it fails. It does say now something like DFU must have been started from an external source, but error is still 4014. I've tried with and without the battery plugged in and using the the external Apple power supply, but still the same problem.

[mon2]

Error code 4014 = appears to be a NAND flash fault on assorted Apple products. Can you confirm the voltage rails for the nand flash?

[luckydip]

Error code 4014 = appears to be a NAND flash fault on assorted Apple products. Can you confirm the voltage rails for the nand flash?

Sorry to hijack this thread but its a NAND related question. Working on a Air 820-02016, had extensive liquid damage around SPI/SOC which I hopefully sorted. Machine powers straight to DFU but when I restore get the 4014 error. Checked all the awake around NAND

PP0V88_AWAKE_NAND, PP1V25_AWAKE_NAND, PP2V5_AWAKE_NAND all present.

Any other power rails to check or dead NANDS? thanks

[Zparts01]

I didn't get to this message before now mon2, but I have re-flashed the original bin to U4770 and now I'm getting 20v and every 20 seconds the amps go up to between 0.45 - 0.50 amps, then start back at zero and climb back up. Not after some time goes by I get a timeout "Gave up waiting for device to transition from DFU state to DFU state. [com.apple.MobileDevice.MobileRestore – 0xFCA (4042)" Also, under thermal camera I see small pulses of heat coming from U6903 if that information helps.

[mon2]

Measure the voltage to ground of PP3V3_G3H_RTC (created by U6903). If this power rail is not 3v3 -> remove all power -> meter in resistance mode -> measure the resistance to ground of PP3V3_G3H_RTC @ L6900 or L6901.

[Zparts01]

It's reading 3.315v so I guess it's not that. Any other thoughts about what it might be?

[luckydip]

It's reading 3.315v so I guess it's not that. Any other thoughts about what it might be?

Are all voltages for U5420 steady?

[Zparts01]

I shall check that when I can get back to it tomorrow luckydip! Thanks

[Zparts01]

With the battery disconnected and the power plugged in and the MacBook is in DFU mode and I get 0.44v, then it starts to drop quickly once I check the pins on U5420.

[Zparts01]

and there is zero volts if it's not in DFU mode. Any idea what it could be luckydip or mon2?

[Zparts01]

No one has anymore ideas?

[Zparts01]

I changed U7710 and U8110 and also U6903 and still same problem.

[mon2]

A bad battery may be to blame. Can you source a known good battery from Amazon or similar for testing? It can be returned if not needed. Alternatively, recommend Mobile Sentrix (Canada). Same conditions apply - they will take it back if not required.

A2289 / 820-01987 no power | Page 2 | Rossmanngroup Forums

[Zparts01]

Thanks mon2! I was thinking about the battery, but I had seen so many post for this board that say you can restore in DFU without a battery or power supply connected that I just wasn't sure if that could be it (I've tried all the different ways, but I do think the battery is almost completely flat anyway). I do use Mobile Sentrix Canada for most of my parts so I guess I will give it a try and let you know!

[Zparts01]

Sadly with a new battery no change at all. I am stumped. What else could it be?

[Zparts01]

Just to add, my voltages for the following all are good, but they are not stable, they go to the correct voltage, then to 0v looping. They loop every few seconds. Here are the measured voltages ...

L7660 PP3V3_G3H 3.3V
L7806 PPVDDCPU_AWAKE 0.75V
L7810 PPVDDCPUSRAM_AWAKE 0.8V
L7811 PPOV82_SLPDDR 0.82V
L7813 PP1V8_SLPS2R 1.8V
L7814 PP1V1_SLPS2R 1.1V
L7817 PPOV9_SLPDDR 0.9V
F7000 PPBUS_G3H 12.2V

[mon2]

What is the voltage and current draw range on the usb C meter? The power adapter is rated to support this logic board? Is the power adapter the original from Apple? Is the power cable the one from Apple or 3rd party? Is it an active cable with e-marker and rated for 100 watts?