Motorola Astro Digital Mobile Radio Xtl5000 Detailled 6881096c74 B Manual

Chapter 5 Troubleshooting Charts
5.1 Introduction
This chapter contains detailed troubleshooting flowcharts and tables. These should be used as a 
guide in determining the problem areas. They are not a substitute for knowledge of circuit operation 
and astute troubleshooting techniques. It is advisable to refer to the related detailed circuit 
descriptions in the theory of operation chapter prior to troubleshooting a radio.
5.2 List of Troubleshooting Charts
Most troubleshooting flowcharts (see Table...

May 25, 20056881096C74-B
5-2Troubleshooting Charts: List of Troubleshooting Charts
NOTE:The term µC might be used in some of the following troubleshooting charts; 
µC = MCU or microprocesor.
RFPA Power Control—No VGBIAS5-45
700–800 MHz
No 16.8 MHz Reference Oscillator Frequency5-46
Poor RX Sensitivity or No RX Audio5-47
RX IF—Poor SINAD or No Audio5-49
RX Back-End—Poor SINAD or No Audio5-50
Low or No RX Injection Signal5-53
Low or No TX Injection Signal5-54
No TX Audio5-55
TX or RX VCO Unlock (Fail...

6881096C74-BMay 25, 2005
Troubleshooting Charts: Troubleshooting Tables 5-3
5.3 Troubleshooting Tables
5.3.1 For Mid Power models
This section contains troubleshooting tables that can help you isolate a problem in your radio.
Table 5-2.  XTL 5000 Troubleshooting Table (700–800 MHz, 380-470 MHz and 136-174 MHz)
SymptomCheck SectionTroubleshooting ProcedureComponent
No TX Modulation Controller Block With 80 mV rms, 1 kHz injected 
to the MIC_HI line and CPS mic 
gain level set to 0 (default), 
check the...

May 25, 20056881096C74-B
5-4Troubleshooting Charts: Troubleshooting Tables
No Keyloading Controller Connect proper KVL keyloader 
and cable and begin keyloading 
by pressing the PTT on the 
keyloader
• Check data activity (5 V levels) 
on Boot_TX/Keyfail* line - 
J0401-25, U0401-5, or C0430.
• Check data activity (5 V levels) 
at U0401-6.
• Check data activity (5 V levels) 
at J0501-14• Absence of data may indicate 
failure with keyloader, cable, 
control head, control head flex, 
J0401, or VR0417.
•...

6881096C74-BMay 25, 2005
Troubleshooting Charts: Troubleshooting Tables 5-5
Radio Dead, Display 
Lights UpClocks
A+Check for 32 kHz clock at 
U0102-4, and 16.8 MHz clock at 
C0106, C0911
Check A+ to the Control Head 
J0401-19, 20Presence 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.
No RX Audio/
Receive Does not 
UnsquelchController...

May 25, 20056881096C74-B
5-6Troubleshooting Charts: Troubleshooting Tables
No RX Audio/
Receive Does not 
Unsquelch (cont.)ABACUS Circuit 
(700-800 MHz)• Check for 20 kHz Frame Sync 
pulse signal at testpoint FS 
(U6000-31)
• Check for 1.2 MHz Clock 
square wave at testpoint 
CLKOUT (U6000-28)
• Check for random data pattern 
at testpoint DOUTA (U6000-29)
• Check for Clock Oscillator at 
R6003 (18 MHz)
• Check for Local Oscillator at 
C6026 (71.1 MHz or 75.6 MHz)• Absence of signal causes no 
receive....

6881096C74-BMay 25, 2005
Troubleshooting Charts: Troubleshooting Tables 5-7
5.3.2 For High Power models and UHF R2 Mid Power
This section contains troubleshooting tables that can help you isolate a problem in your radio.
Table 5-3.  XTL 5000 Troubleshooting Table (136-174 MHz, 380-470 MHz and 450-520 MHz Mid Power)
SymptomCheck SectionTroubleshooting ProcedureComponent
No TX Modulation Controller Block With 80 mV rms, 1 kHz injected 
to the MIC_HI line and CPS mic 
gain level set to 0 (default), 
check...

May 25, 20056881096C74-B
5-8Troubleshooting Charts: Troubleshooting Tables
Radio Dead, Display 
Does Not Light UpBlown Fuse Check fuse in red lead of power 
cable (or green lead if used)Absence of signal may indicate 
failure with J0401, J0402, 
VR0412, or VR0402
Controller Section • Check for IGNITION at J0401-
27, 28
• Check for A+ at Q0503, 
VR0950, J0401-19,21, or 
TP0414• Absence of signal may indicate 
failure with J0401
• Absence of signal may indicate 
failure with J0950, J0401 or 
VR0950...

6881096C74-BMay 25, 2005
Troubleshooting Charts: Troubleshooting Tables 5-9
No RX Audio/
Receive Does not 
UnsquelchController Block (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• Short may indicate failure...

May 25, 20056881096C74-B
5-10Troubleshooting Charts: Troubleshooting Tables
No RX Audio/
Receive Does not 
Unsquelch (cont.)ABACUS Circuit 
(700-800 MHz)• Check for 20 kHz Frame Sync 
pulse signal at testpoint FS 
(U6000-31)
• Check for 1.2 MHz Clock 
square wave at testpoint 
CLKOUT (U6000-28)
• Check for random data pattern 
at testpoint DOUTA (U6000-29)
• Check for Clock Oscillator at 
R6003 (18 MHz)
• Check for Local Oscillator at 
C6026 (71.1 MHz or 75.6 MHz)• Absence of signal causes no 
receive....