PMIC Replaced - Missing voltages

Question

iPad Air LTE

iPad Air Wi-Fi + Cellular, model no. A1475. Available in Space Gray or Silver, with 16/32/64/128 GB configurations.

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I have an iPad Air (1st gen) which I have replaced the PMIC. The reason for that is because the iPad charges only when it was switched off.

I have lifted the following pads during removal of the PMIC:

Dont know If this is the cause of the problems below:

No backlight (filters are good)
Missing voltage on PP3V0_SPARE1
Missing voltage on PP3V0_S2R_SENSOR
Missing voltage on PP3V3_ACC
No Heat on the board, and I can see apple logo on screen without backlight looping.

Anyone can point me in the right direction or explaining those missing voltage lines could be a BIG help understanding the situation.

Thanks :)

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bert.harmidomski @tojaert 평판: 4.8k 11 5 1 · Answer 1 · 2020-11-24T11:27:42-07:00

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hello Peter,

too high temp and flow you use for taking off a glue and a ic. It seems like cpu overheated. Have you stencil for reballing?

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Yes! I have used a brand new PMIC already reballed.

Also I have measured around all Caps with Multimeter Diod mode wich resulted NO short on the board.

Or you suggest I should reball the CPU???

this is dependent to board measurement. But it looks like. I would measure RAM and NAND beforehand but it looks like yes, I would do a CPU reballing.

sometimes, problem is in technical's hand work. Are you sure IC is sitting down correctly?