Motorola ASTRO XTL 1500 Detailed Service Manual page 168

Troubleshooting Charts: Troubleshooting Tables
Table 5-3. XTL 1500 Troubleshooting Table (450-520 MHz) (Continued)
Symptom
Radio Dead, Display Regulators
Lights Up with FL
01/90
Flex/Control Head
Clocks
Flex, Control Head
No RX Audio/ Controller Block
Receive Does not
Unsquelch
Regulators
6815854H01-A
Check Section Troubleshooting Procedure
• Check for SW_B+ at Q0503,
U0500-4, U0950-4, U0951-4
• Check for 9.3 V at U0500-5,
U0950-5, U0951-5.
• Check for 5 V at U0503-5, 3 V
at U0962-3, 2.85 V at U0501-1,
1.85 V at U0507-1, 1.55 V at
U0502-1
Check for SW_B+_CH at J0401-
33,34, TP0413, or pin 21 of P502
(on control head)
Check for 32 kHz clock at
U0102-4, and 16.8 MHz clock at
C0106, C0911
Check for SSI signal on CH.
(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
Component
• Absence of signal may indicate
failure with Q0503
• Absence of signal may indicate
failure with U0500, U0950, or
U0951 (9 V Regulators)
• Absence of signal may indicate
failure with U0503, U0962,
U0501, U0507, or U0502 (5 V,
3 V, 2.85 V, 1.85 V, and 1.55 V
Regulators)
Absence of signal may indicate
failure with flex, control head
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
No signal indicate missing/failure
of SSI components (MUXes,
jumper resistors) on CH board,
flex contamination or failure.
Needs rework or changing of
flex.
• 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
June 15, 2005
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