Motorola 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 5-1) end by pointing to an IC to replace. Before replacing 
any IC, it is good practice to verify power supplies and grounds to the affected IC and trace continuity 
to the malfunctioning signal and related circuitry. For example, if a clock signal is not available at a 
destination IC, continuity from the source IC should be checked before replacing the source IC.
Table 5-1.  List of Troubleshooting Charts
DescriptionPage
VHF (136–174 MHz)
Poor RX Sensitivity or No RX Audio5-15
RX IF—Poor SINAD or No Audio5-17
RX Back-End—Poor SINAD or No Audio5-18
Low or No RX Injection Signal5-21
Low or No TX Injection Signal5-22
TX or RX VCO Unlock (Fail 001)5-23
No Output Power at TX Mode5-25
No Output Power and IDC < 2A at TX Mode5-26
UHF Range 1 (380–470 MHz) and UHF Range 2 (450–520 MHz)
No 16.8 MHz Reference Oscillator Frequency5-27
Poor RX Sensitivity or No RX Audio5-28
RX IF—Poor SINAD or No Audio5-30
RX Back-End—Poor SINAD or No Audio5-32
Low or No RX Injection Signal5-35
Low or No TX Injection Signal5-36
No TX Audio5-37
TX or RX VCO Unlock (Fail 001)5-38
RF Power Amplifier (RFPA)—No or Low TX Power Output5-40 
						

							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 001)5-56
RF Power Amplifier (RFPA)—No or Low TX Power Output5-58
RFPA Power Control—No K9.1V5-63
RFPA Power Control—No VGBIAS5-64
RFPA Power Control—No or Low TX RFPA_CNTRL5-65 Table 5-1.  List of Troubleshooting Charts (Continued)
DescriptionPage 
						

							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 following levels.
• 80 mVrms at TP0200, U0209-
4, J0401-4.
• 36 mV rms at TP0201.
• 20 mV rms at U0201-1, 
TP0202.
• 36 mV rms at U0201-7, 
TP0203.
• 36 mV rms at U0200-17.
• > 150 mV rms at U0900-1.
• > 150 mV rms at FL0900-5.
• > 150 mV rms at U0902-14
• > 150 mV rms at R6782• Absence of signal may indicate 
failure with U0209 (MUX), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0209 (MUX), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0202 (EPOT), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0202 (EPOT), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0200 (Codec)
• Absence of signal may indicate 
failure with U0901 (Urchin), 
U0900 (Modulation DAC), or 
U0001 (Microprocessor Board)
• Absence of signal may indicate 
failure with U0901 (Urchin), or 
FL0900 (Filter)
• Absence of signal may indicate 
failure with U0902 (MUX)
• Presence of signal may 
indicate a aproblem in RF 
section
Flex/Control Head Check that MIC_HI is getting to 
controller at VR0412, VR0421, 
C0438, C0207, C0234, or R0204Absence of signal may indicate 
failure with flex, control head, 
VR0412, or VR0421 
						

							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.
• Absence of signal may indicate 
failure with U0401 (MUX) or 
Q0404
• Absence of signal may indicate 
failure with J0501; Presence of 
signal may indicate failure of 
secure interface board or UCM/
Secure module, which would 
need replacing
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-
20, J0402-18, VR0402, 
VR0412
• Check for A+ at Q0503, 
VR0950, J0401-19,21, or 
TP0414• Absence of signal may indicate 
failure with J0401, J0402
• Absence of signal may indicate 
failure with J0950, J0401
Flex/Control Head Check for SW_B+_CH at J0401-
17, TP0413, or pin 21 of P502 
(on control head)Absence of signal may indicate 
failure with flex, control head
Radio Dead, Display 
Lights UpRegulators • 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• 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)
Flex/Control Head Check for SW_B+_CH at J0401-
17, TP0413, or pin 21 of P502 
(on control head)Absence of signal may indicate 
failure with flex, control head
SB9600 Check for logic transitions at 
J0401-31 thru 34, J0402-3 thru 
6, or U0606-4,7,9,12Absence of signal may indicate 
failure with U0606 MUX), 
VR0408, VR0418, Q0610-
Q0613, U0001 (Microprocessor 
Board), control-head flex, or rear 
accessory flex
Table 5-2.  XTL 5000 Troubleshooting Table (700–800 MHz, 380-470 MHz and 136-174 MHz) (Continued)
SymptomCheck SectionTroubleshooting ProcedureComponent 
						

							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 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 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
Regulators See description for No VOCON 
Powerup
ABACUS Circuit 
(380-470 MHz, 
450-520 MHz)• Check for 20 kHz Frame Sync 
pulse signal at testpoint FS 
(U5002-31)
• Check for 1.2 MHz Clock 
square wave at testpoint 
CLKOUT (U5002-28)
• Check for random data pattern 
at testpoint DOUTA (U5002-29)
• Check for Clock Oscillator at 
R5025 (18 MHz)
• Check for Local Oscillator at 
C5058 (71.1 MHz or 75.6 MHz)• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of Clock signal 
causes no receive. Possible 
U5002 (ABACUS), Clock VCO, 
or U0001 (Microprocessor 
Board) failure
• Absence of LO signal causes 
no receive. Possible U5002 
(ABACUS), or LO VCO
Table 5-2.  XTL 5000 Troubleshooting Table (700–800 MHz, 380-470 MHz and 136-174 MHz) (Continued)
SymptomCheck SectionTroubleshooting ProcedureComponent 
						

							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. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of Clock signal 
causes no receive. Possible 
U6000 (ABACUS), Clock VCO, 
or U0001 (Microprocessor 
Board) failure
• Absence of LO signal causes 
no receive. Possible U6000 
(ABACUS), or LO VCO
Radio Will Not Turn 
OffOn/Off Switch 
(Control Head)Check for SW_B+_CH at 0 V at 
J0401-17, TP0413A high voltage may indicate 
failure with the control head
Radio Will Not Turn 
Off (continued)Emergency Circuit Check for 0 V at Timer U0506-3, 
U0508-2,4A high voltage may indicate 
failure with U0506, or that the 
EMERGENCY line is not 
grounded by the rear accessory 
cable
SW_B+ Sense 
CircuitCheck that U0604-7 is low (0 V) 
and that SOFT TURN OFF is low 
(0 V) at D0501Absence of this voltage may 
indicate failure with U0604 (Op-
Amp) or with U0001 
(Microprocessor Board)
Table 5-2.  XTL 5000 Troubleshooting Table (700–800 MHz, 380-470 MHz and 136-174 MHz) (Continued)
SymptomCheck SectionTroubleshooting ProcedureComponent 
						

							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 the following levels.
• 80 mVrms at TP0200, U0209-
4, J0401-57.
• 80 mV rms at TP0201.
• 2.5 Vdc at U0201-8.
• 80 mV rms at U0201-7, 
U0201-7, TP0203.
• 36 mV rms at U0200-17.
• > 150 mV rms at U0900-1.
• > 150 mV rms at FL0900-5.
• > 150 mV rms at U0902-14
• > 150 mV rms at R6782• Absence of signal may indicate 
failure with U0209 (MUX), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0209 (MUX), or 
U0201 (Op-Amp)
• Absence of DC bias may 
indicate failure with U0201 
(Op-Amp)
• Absence of signal may indicate 
failure with U0202 (EPOT), or 
U0201 (Op-Amp)
• Absence of signal may indicate 
failure with U0200 (Codec)
• Absence of signal may indicate 
failure with U0901 (Urchin), 
U0900 (Modulation DAC), or 
U0001 (Microprocessor Board)
• Absence of signal may indicate 
failure with U0901 (Urchin), or 
FL0900 (Filter)
• Absence of signal may indicate 
failure with U0902 (MUX)
• Presence of signal may 
indicate a aproblem in RF 
section
Flex/Control Head Check that MIC_HI is getting to 
controller at VR0412, VR0421, 
C0438, C0207, C0234, or R0204Absence of signal may indicate 
failure with flex, control head, 
VR0412
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 - 
J0401-44.
• Check data activity (5 V levels) 
at J0501-14• Absence of data may indicate 
failure with keyloader, cable, 
control head, control head flex, 
J0401.
• Absence of signal may indicate 
failure with J0501; Presence of 
signal may indicate failure of 
secure interface board or UCM/
Secure module, which would 
need replacing 
						

							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
Flex/Control Head Check for SW_B+_CH at J0401-
33,34, TP0413, or pin 21 of P502 
(on control head)Absence of signal may indicate 
failure with flex, control head
Radio Dead, Display 
Lights UpRegulators • 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• 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)
Flex/Control Head Check for SW_B+_CH at J0401-
33,34, TP0413, or pin 21 of P502 
(on control head)Absence of signal may indicate 
failure with flex, control head
SB9600 Check for logic transitions at 
J0401-13 thru 16, or U0606-
4,7,9,12Absence of signal may indicate 
failure with U0606 MUX), 
VR0408, VR0418, Q0610-
Q0613, U0001 (Microprocessor 
Board), control-head flex, or rear 
accessory flex
Radio Dead, Display 
Lights UpClocks
RemoteCheck for 32 kHz clock at 
U0102-4, and 16.8 MHz clock at 
C0106, C0911
Check for A+ at J6Presence of signals may indicate 
failure with U0001 
(Microprocessor Board). 
Absence of signals may indicate 
failure with U0102 (Inverter) or 
with FGU reference oscillator 
circuit
Check F0400.
Check the flex.
Table 5-3.  XTL 5000 Troubleshooting Table (136-174 MHz, 380-470 MHz and 450-520 MHz Mid Power) 
SymptomCheck SectionTroubleshooting ProcedureComponent 
						

							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 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
Regulators See description for No VOCON 
Powerup
ABACUS Circuit 
(380-470 MHz, 
450-520 MHz)• Check for 20 kHz Frame Sync 
pulse signal at testpoint FS 
(U5002-31)
• Check for 1.2 MHz Clock 
square wave at testpoint 
CLKOUT (U5002-28)
• Check for random data pattern 
at testpoint DOUTA (U5002-29)
• Check for Clock Oscillator at 
R5025 (18 MHz)
• Check for Local Oscillator at 
C5058 (71.1 MHz or 75.6 MHz)• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U5002 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of Clock signal 
causes no receive. Possible 
U5002 (ABACUS), Clock VCO, 
or U0001 (Microprocessor 
Board) failure
• Absence of LO signal causes 
no receive. Possible U5002 
(ABACUS), or LO VCO
Table 5-3.  XTL 5000 Troubleshooting Table (136-174 MHz, 380-470 MHz and 450-520 MHz Mid Power) 
SymptomCheck SectionTroubleshooting ProcedureComponent 
						

							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. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of signal causes no 
receive. Possible U6000 
(ABACUS) failure or U0001 
(Microprocessor Board) failure
• Absence of Clock signal 
causes no receive. Possible 
U6000 (ABACUS), Clock VCO, 
or U0001 (Microprocessor 
Board) failure
• Absence of LO signal causes 
no receive. Possible U6000 
(ABACUS), or LO VCO
Radio Will Not Turn 
OffOn/Off Switch 
(Control Head)Check for SW_B+_CH at 0 V at 
J0401-17, TP0413A high voltage may indicate 
failure with the control head
Radio Will Not Turn 
Off (continued)Emergency Circuit Check for 0 V at Timer U0506-3, 
U0508-2,4A high voltage may indicate 
failure with U0506, or that the 
EMERGENCY line is not 
grounded by the rear accessory 
cable
SW_B+ Sense 
CircuitCheck that U0604-7 is low (0 V) 
and that SOFT TURN OFF is low 
(0 V) at D0501Absence of this voltage may 
indicate failure with U0604 (Op-
Amp) or with U0001 
(Microprocessor Board)
Table 5-3.  XTL 5000 Troubleshooting Table (136-174 MHz, 380-470 MHz and 450-520 MHz Mid Power) 
SymptomCheck SectionTroubleshooting ProcedureComponent