Motorola APX 7500 Detailed Service Manual page 149

Troubleshooting Charts and Error Codes Troubleshooting Charts
Verify the "Crosspatch-Hardware PTT Selection" in
the Consolette Configuration is set to Hardware
PTT. Inject a 1kHz, 300 mVrms tone from a 600
Ohm source into Accessory Connector's AUX_TX
(J104-17) & short PTT* (J104-10) to ground.
Does the
Consolette key up and
begin transmitting?
Yes
Is the Consolette
TX dev. 60% of rated
system deviation?
Yes
STOP
Figure 7-31. APCO TX Audio - A
68009482001
No
Is the APX7500 mobile
operating properly?
Yes
Does U1809-16 on the
Consolette Mainboard
measure ~0Vdc (GND)?
Yes
Reprogram/Replace
Consolette Mainboard.
No
Is the APX7500 mobile
operating properly?
Yes
Is the Crosspatch In (TX) Gain
Setting in the Consolette
Configuration properly tuned?
Yes
Is there a 1kHz,
~75mVrms tone at
U1800-3 on the Consolette
Mainboard?
Yes
Reprogram/Replace
Consolette Mainboard.
Refer to the APX7500
Detailed Service
No
Manual for correct
operation and
troubleshooting.
Does U1809-4
No
measure ~0Vdc
(GND)?
Yes
Replace U1809.
Refer to the APX7500
Detailed Service
No
Manual for correct
operation and
troubleshooting.
Refer to the "Transmit
No
Audio Tuning –
AUX_TX" section of the
manual.
Is there a 1kHz,
No
~75mVrms tone at
U1800-6?
Yes
Verify U1800, C1817, R1814
& R1816 are placed
properly.
Is ~3.3Vdc
present at
U1800-2?
Yes
Does U1800-1
measure ~2.8Vdc?
Yes
Replace U1800.
7-33
Verify PTT* (J104-10) is
being routed properly
No
through the low speed
board & flex cable to
U1809-4.
Verify R1811, R1812, C1808,
No
C1816 & U1801 are placed
properly & the resistor values
are correct.
Parts placed properly
There may be an issue
No
with the internal board
routing of VCC_3.3V.
No
Reprogram/Replace
Consolette Mainboard.
September 9, 2011