Introduction
Does your power button not respond? Does your screen remain off even after you press the power button many times? Replacing the motherboard may solve these problems.
Tools
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Use the small suction cup to lift the back panel:
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Press the small suction cup on to the middle of the back panel.
 
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While holding the Sony Xperia Z ultra down with your left hand, slightly pull the small suction cup upwards to create a small opening between the back panel and the front panel.
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While continuing to pull the small suction cup upwards, insert the spudger in the small opening.
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Pry the front panel downwards with the spudger while continuing to pull the small suction cup upwards.
 
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Remove the following six screws with a Phillips #000 screwdriver:
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five silver 2.1 mm screws
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one gold 3.1 mm screw
 
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Pry the plastic motherboard shield open by placing the spudger under the shield and running it along the edges.
 
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Remove the metal shield cover by prying its right end upwards with the flat part of the spudger.
 
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Remove the mic connection from the motherboard ribbon by prying it upwards with the spudger.
 
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Gently pry the black plastic spacer upwards with the spudger.
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Remove the black plastic spacer from the phone by gently pulling it upwards.
 
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Use the flat part of a spudger to detach the vibration motor connection. It is a tiny white box with red and black wires leading to the motor.
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Once the connection has been removed, slide the spudger underneath the vibration motor to release it from the adhesive.
 
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Pry the small black metal bracket off with the spudger.
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Remove the small black metal bracket by lifting it upwards and outwards.
 
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Detach the orange ribbon by wedging the spudger between the phone's casing and the ribbon. This will help prevent damage to the strip.
 
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Detach smaller orange ribbon by wedging the spudger between the phone's casing and the ribbon. This will help prevent damage to the strip.
 
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Pry up the connection strip at the end of the motherboard using the flat part of the spudger to free the motherboard.
 
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To reassemble your device, follow these instructions in reverse order.