Motorola APX 7500 Detailed Service Manual page 132

7-16
~300mVrms tone present
Is there a 1kHz,
~300mVrms tone at
R1885?
Yes
Is there continuity
between R1885 on the
Mainboard and P100-2 & P100-3
on the low speed board?
Yes
Is P100
connected properly to
the audio jack?
Yes
STOP
September 9, 2011
Troubleshooting Charts and Error Codes Troubleshooting Charts
Verify R1883, R1884, C1823,
No
C1850, U1802, C1824 & R1885
are placed properly & the
resistor values are correct.
Is ~1.35Vdc
present at U1802-12 &
~3.3Vdc present at
U1802-4?
Yes
Replace U1802.
Verify RX_AUDIO_BUFF is being
No
routed properly from R1885
through the flex cable & low
speed board to P100-2 & P100-3.
No
Make the proper connections
between P100 and the audio jack.
There may be an issue with the
No
internal board routing of
VCC_1.35V and/or VCC_3.3V.
Figure 7-14. Audio Jack RX - B
68009482001