Motorola ASTRO XTL 1500 Detailed Service Manual page 165

5-4
Table 5-2. XTL 1500 Troubleshooting Table (700–800 MHz, 380-470 MHz and 136-174 MHz) (Continued)
Symptom
Radio Dead, No Flex/Control Head
Display, No LED
Backlighting (cont.)
Clocks
A+
No RX Audio/ Controller Block
Receive Does not
Unsquelch
Regulators
June 15, 2005
Check Section Troubleshooting Procedure
Check for SW_B+_CH at J0401-
17, TP0413.
Check for all voltages in CH;
1.55V, 1.88V, 2.8V, 3.3V, 5V and
UNSW_VCC (3.0V).
Check for Board ID resistors on
CH. Should match schematics.
Check for 32 kHz clock at
U0102-4, and 16.8 MHz clock at
C0106, C0911
Check A+ to the Control Head
J0401-19, 21
(Inject 1 kHz tone, 3 kHz
deviation into radio antenna, set
volume to rated audio.
• Check for speaker leads
shorted to ground, or at U0204-
4, 6.
• Check for > 30 mV rms audio
at audio PA input, U0204-1,9.
• Check for > 30 mV rms audio
at U0206-8 or TP0205.
• Check for > 30 mV rms audio
at U0210-6 or U0200-2.
• Check that U0204-8 is >10 V
See description for No VOCON
Powerup
Troubleshooting Charts: Troubleshooting Tables
Component
Absence of signal may indicate
failure with flex, control head
Absence/mismatch warranats
replacement to correct location.
Presence of signals may indicate
failure with U0001
(Microprocessor Board).
Absence of signals may indicate
failure with U0102 (Inverter) or
with FGU reference oscillator
circuit
• Absence of voltage F0400 may
be blown.
• Short may indicate failure with
VR0400, VR0412, or U0204
• Presence of signal may
indicate failure with U0204
(Audio PA)
• Presence of signal may
indicate failure with U0206
(Log-POT)
• Presence of signal may
indicate failure with U0210
(MUX); Absence of signal may
indicate failure with U0200
(CODEC), or U0001
(Microprocessor Board)
• Absence of >10V may indicate
failure with Q0200 or U0001
6815854H01-A