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iPhone 7 - No Wake - or is it?

August 13, 2020

iPhone 7 - Intel

 

 Job comes in with a bit of history.

Phone was plugged in to charger all night and when powered on in the morning it booted but as soon as it went to stdby niether home button or power button would bring up the display.

So they described a sleep wake issue not to be confused with raise to wake.

It wasnt a sleep wake issue at all and no coils on the GPU circuit were harmed in this job.

The original description gave me a bit of an insight into the real issue.

Seems like a charging issue to begin with, if my thinking was correct.

When I received it I opened it up to check the battery was connected securely and covers were in place.

So without touching anything I try to simulate the customer and plug in to my charger which has an amp meter attached and it showed 0.00ma @ 4.99v

So its not drawing anything current wise so the battery is not connected.

I open the cover and see the battery FPC was askew and not secure at all.

Once secured it was able to start the charging process from dead (battery icon)

 

If this happens Tigris is most likely ok as is Tristar.

I let it see if it would fully charge and boot and it did, but as soon as it was on for a bit it looked like it was in standby mode and no home button or power button would bring up the display.

The reason for this was .....the device was OFF.

It powered off due to the switchline monitoring on the CPU/AP side.

Tigris can be self sufficient and handle charging on its own with out any cpu powered up, but when the iOS has booted to springboard then the AP/CPU handles monitoring over i2c.

I2C cannot work when the device is off right! 

 

Which is why Tigris can charge when the device is OFF. It uses a different method that I have posted about before.

Anyway lets use a simple test: WITHOUT A METER :)

Now plug the device into the PC / Laptop  for pc comms and a nice old 5V0 usb voltage.

Now leave the device on and check the wake sleep function when the display goes off, it will only turn off the backlight the image will still be visible under light or torch and AP/GPU will power back on.

Device is still fully charged and wakes using home button and power button. NO ISSUES

The device is on with no issues connected to the PC comms.

Battery data is available.

 

On battery power only it does the same thing again no wake up display - or more like powered off again.

The battery SWI tested about 100 above what I wanted to see so I removed the Battery FPC ( ALRIGHT I USED A METER IN THE END)

 


At times I would get varying volts on the SWI.

I also noticed that the PP5V0 ends of the dock flex fpc were spongey and replace the Dock FPC.

The phone now charges, and stays charging, on , wake sleep home button and so on...

The battery wasnt ever being charged overnight as it wasnt connected and the AP SWI takeover once booted
could not detect the battery as the connector was damaged.
 

Panic Log confirmed Battery issue with Thermal Monitor string:

 

So at first it would not charge.


Then it could charge from dead batt

 

Then it would power off once booted

 

Had no issues when connected to pc and charged as well, as wake sleep home button function. (as it was on and not OFF)

 

Battery only power resulted in fault coming back and turning off.

 

Dodgy PP5V0 usb at the dock FPC and poor SWI comms on the Batt FPC.

 

Hope this helps a few.

Regards Dee

 

 

 

 

 

 

 

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