Sony Xpreia acro S Working Instructions page 149

Problem Areas: Ambient Light Sensor
3. If the light sensor, the FPC or the BtB connector of the
PBA Flex Module is damaged – replace the PBA Flex
Module.
4. Replace PBA.
1267-1086 Rev 2
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Sony Mobile Communications AB – Company Internal
Troubleshooting Guide (mech)
37(72)