Motorola Moto X Force Troubleshooting Manual page 34

Microphones Troubleshooting
If a mic is not functioning...
• Check to make sure the microphone and mic ports are not blocked.
• Check to make sure the mic gasket and mic grommets are seated properly (Mic 1/3/4/5). Check to
make sure the J4600 B2B connector is seated properly (MIC 2 only).
• Check the microphone for diaphragm debris indicating a shattered diaphragm. Look under a
microscope to view inside the microphone port for damage or debris near port hole or surrounding the
microphone area where tiny, shiny particulate material may be visible when varying viewing angle.
• Check to make sure no capacitors on any of the applicable mic lines are shorted or damaged.
• Check the mic bias C4500 (Mic1), C4510 (Mic2), C4520 (Mic3), C4530 (Mic4), C4540 (Mic5). The mic
bias should be 1.8VDC when the microphone is enabled.
• If the failure is no microphone audio, check mic loopback through CQA at the board level with a
display connected. (Mic loopback may be easier to check with a headset plugged in, in which case
the rear hsg assy may be req'd.)
• If there is no audio during mic loopback, inject a 35mVrms, 1kHz sine wave onto the mic signal side of
C4501 (Mic1), C4511 (Mic2), C4521 (Mic3), C4531 (Mic4), C4541 (Mic5) and listen for the tone
during loopback. If you can hear the tone now, you know either the mic is bad, or there's a process
defect with the mic-to-PCB connection.
• X-ray the mic to check for process defects.
•
If swapping the microphone fixes the issue, the bad microphone should be sent to the supplier for FA.
MOTOROLA CONFIDENTIAL
Moto X Force/DROID Turbo 2
BASEBAND TROUBLESHOOTING GUIDES