Motorola Astro Digital Mobile Radio Xtl5000 Detailled 6881096c74 B Manual

							6881096C74-BMay 25, 2005
Troubleshooting Procedures: 700–800 MHz Main Board Troubleshooting 4-27
13
VRO 3.0-V supply for reference oscillator warp circuitry
14VMULT2 Not used
15VMULT1 Not used
16INDMULT Not used
17— No connection
18REFSEL Not used
19FREFOUT Not used
20AVDD 3.0-V supply (analog)
21VBPASS Not used
22GND Ground (analog)
23XTAL1 16.8 MHz reference oscillator input
24XTAL2 Not used
25WARP Reference oscillator warp output
26SFCAP Superfilter bypass node
27SFBASE Superfilter control node for Q6759
28SFOUT Superfilter output
29— No connection
30SFIN Superfilter supply input
31— No connection
32PREIN Prescalar input
33GROUND Ground (prescalar)
34PRE_VDD 3.0-V supply
35PVREF Not used
36DVDD 3.0-V supply (digital)
37TEST1 Not used
38TEST2 Not used
39CPB2 Phase detector bias input
40CPB1 Phase detector bias input
41MODOUT Modulation output
42CCOMP Not used
43IOUT Phase detector normal mode output
44GND Ground (phase detector)
45IADAPT Phase detector adapt mode output
46ADAPTSW Phase detector adapt switch
47VCP High-voltage supply for phase detector
48AUX1 Auxiliary logic output, high selects U6754 OSC1 Table 4-15.  LV Frac-N U6751 Pin Descriptions (700–800 MHz) (Continued)
Pin No.Pin NameDescription 
						

							May 25, 20056881096C74-B
4-28Troubleshooting Procedures: Standard Bias Tables
Figure 4-12.  Waveform Representation During Programming of the LV Frac-N IC (U6751)
NOTE:The above waveforms are representations only.
4.9.3 No or Low Output Power (TX or RX Injection)
In addition to the schematic and theory of operation, refer to the transmitter injection troubleshooting 
flowchart and the receiver injection trouble shooting flowchart in Chapter 5. The charts will guide you 
through a sequence of tests and checks designed to isolate problems in the Transmitter or receiver 
injection strings.
4.9.4 No or Low Modulation
In addition to the schematic and theory of operation, refer to the transmitter no TX Audio 
troubleshooting flowchart in Chapter 5. The chart will guide you through a sequence of tests and 
checks designed to isolate problems in the Transmitter Audio section of the FGU.
4.9.5 Troubleshooting the Back-End
Refer to “5.6.36 RX Back-End—Poor SINAD or No Audio (700–800 MHz)—Part 1 of 3” on page 5-
50.
4.10 Standard Bias Tables
Table 4-16, below, outlines some standard supply voltages and system clocks that should be present 
during normal operation. These should be checked as a first step to any troubleshooting procedure.
Table 4-16.  Standard Operating Bias: Power Lines
Nominal ValueSignal NameRange/StateProbe Locations
13.8 V A+ (at DC connector) 11.0 to 16.6 V J0401-20, TP0414
13.8 V IGNITION 11.0 to 16.6 V J0401-19, J0401-21
13.8 V SW_A+
(on board only)11.0 to 16.6 V U0500-4, Q0503
13.8 V SW_B+ (from C.H.) 11.0 to 16.6 V TP0413, J0401-17
2.83 V SW_B+_SENSE No change U0604-7
2.5 V SW_B+_ON_OFF
(on board only)2 to 3 V Q0505-1, Q0504-1
9.1 V 9.3V_ABACUS No change U0505-1
9.1 V 9.3V No change TP0951, TP0950
Pin 9 (Chip Select)
Pin 7 (Data)
Pin 8 (Clock)
MAEPF-27805-O 
						

							6881096C74-BMay 25, 2005
Troubleshooting Procedures: Standard Bias Tables 4-29
.
9.18 V 9V No change U0500-5
5 V 5V_ABACUS No change U0505-3
5 V VCC_5 No change J0401-23, U0507-8, 
U0503-3, U0502-8, 
U0501-8
3 V VCC_3 No change U0962-5
2.85 V LV_DETECT When A+ drops too far 
below 9 V, this line goes 
to 0 VU0504-1
2.85 V STO
(at microprocessor)No change TP0500
2.85 V VCC_2.85 No change U0501-1
1.86 V Vpp No change TP0400
1.85 V VCC_1.8 1.84 to 1.87 V U0507-1
1.55 V VCC_1.55 No change U0502-1
1.42 V VAG No change U0206-1, U0201-3
Note: Do not KEY UP unless the board is inside a chassis.
Table 4-17.  Standard Operating Bias: Clock and Control Lines
Nominal ValueSignal NameRange/StateProbe Locations
(See “Chapter 6 
Troubleshooting 
Waveforms” on 
page 6-1)SB9600__BUS + Idle=High (4 V to 5 V) J0402-3, J2-2
SB9600__BUS - Idle=Low (0 V) J0402-5, J2-3
SB9600__BUSY Idle=Low (0 V) J0402-4, J2-9
SB9600__RESET Idle=Low (0 V) J0402-6, J2-8
Note: Use chassis as GND when measuring on an oscilloscope.
(See “Chapter 6 
Troubleshooting 
Waveforms” on 
page 6-1)USB_PWR 5.1 V J0402-12, J2-12
USB_DATA + J0402-11, J2-7
USB_DATA - J402-13, J2-6
Note: Use chassis as GND when measuring on an oscilloscope.
(See “Chapter 6 
Troubleshooting 
Waveforms” on 
page 6-1)RS232__UARTA_TX Output voltage level is 
the same as BOOT TXTP0407, J2-7
RS232__UARTA_RX Input level depends on 
inputting devices levelsTP0408, J2-9
RS232__UARTA_CTS Flow control line—not 
used alwaysTP0409, J2-8
Table 4-16.  Standard Operating Bias: Power Lines (Continued)
Nominal ValueSignal NameRange/StateProbe Locations 
						

							May 25, 20056881096C74-B
4-30Troubleshooting Procedures: Standard Bias Tables
RS232__UARTA_RTS Flow control line—not 
used alwaysTP0410, J2-10
Note: Use chassis as GND when measuring on an oscilloscope.
Approx. 0 V Emergency  Idle = deactivated = 
groundedJ2-15, J0402-28, 
TP0403
1.88 V Emergency Activated = ungrounded J2-15, J0402-28, 
TP0403
Approx. 0 V Emergency_sense Deactivated U508-4
2.85 V Emergency_sense Activated U508-4
(See “Chapter 6 
Troubleshooting 
Waveforms” on 
page 6-1)Boot_TX Same as UARTA_TX J0401-26, P502-10
Boot_RX Same as UARTA_RX J0401-25, P502-2
2.85 V Cable_Detect No prog. cable inserted U0402-4
0 V Cable_Detect Prog. cable inserted at 
P502U0402-4
3.5 V Boot_Data_enable No prog. cable inserted
0 V Boot_Data_enable Prog. cable inserted at 
P502U0402-2
0 V Opt_B+_bootsel_Vpp No prog. cable inserted J0401-22, TP0401
8 V Opt_B+_bootsel_Vpp Prog. cable inserted @ 
P502J0401-22, TP0401
(See “6.2.5 
32 kHz Clock 
Waveform” on 
page 6-4)32 kHz U0102-4
(See “6.2.4 
16.8 MHz Clock 
Waveform” on 
page 6-3)16.8 Mhz C0911 near U0903
Note: Do not KEY UP unless the board is inside a chassis.
Table 4-18.  Standard Operating Bias: Audio Lines
Nominal ValueSignal NameRange/StateProbe Locations
9.2 V Mic_Hi When microphone 
connected (expects 
80 mV input) (line has 
microphone bias)TP0402, J0401-4
Table 4-17.  Standard Operating Bias: Clock and Control Lines (Continued)
Nominal ValueSignal NameRange/StateProbe Locations 
						

							6881096C74-BMay 25, 2005
Troubleshooting Procedures: Standard Bias Tables 4-31
9.2 V Mic_Hi When microphone 
disconnectedTP0402, J0401-4
13 V to 16 V Mic_Hi When programming 
cable insertedTP0402, J0401-4
Note: Do not press the PTT unless the PCB is inside a chassis even for a moment to check a line.
Permanent RF hardware damage can occur to the board due to no heatsinking.
9.2 V Aux_Mic = [ A(tx) ]
(transmit audio)Expects 300 mV input 
(APCO default)
Expects 80 mV input 
(motorcycle use)J0401-6, J2-23
2.84 V Aux_PTT = [ PTT ] Idle = High
Active = Low
Hard-wired PTT, which 
will mute or unmute 
Aux_Mic lineJ0402-24, J2-16
1.4 Vdc to 25 Vdc
(needs ext. cap)Aux_TX (audio input) 300 mV line-level
(no mic bias)J0401-7
0 V Aux_RX (audio input) 300 mV line-level
(Audio PA In)J0401-8
Note: The Mic_Hi audio overrides Aux_TX/Aux_Mic audio, and the speaker is always muted.
0 V Speaker + Muted (output) J2-21, U204-4
Speaker - Muted (output) J2-20, U204-6
26v peak-to-peak 
@volume= 15+Speaker + Unmuted (output) J2-21, U204-4
Speaker - Unmuted (output) J2-20, U204-6
Note: Never ground speaker lines. They are differential, not single-sided.
Use an oscilloscope probe on Spk+ and oscilloscope-probe GND on Spk-.
2.85 V Monitor Idle = High
Activate = LowJ2-22
2.84 V Audio_PA_Enable Q0200-1
1.3 V RX_Filt_Audio = [A(rx) ]
(receive audio/audio 
output)300 mV line-level output J2-21, TP0204
0 V or 5 V Chan_Act = [A(p) ]
(qualified audio 
presence)Idle = Low (0v)
Active = High (5 V)J2-13
HUB This pin causes the 
control head to send 
SB9600 message to the 
radio, indicating when 
HUB is attachedP502-3
Note: Do not KEY UP unless the board is inside a chassis.
Table 4-18.  Standard Operating Bias: Audio Lines (Continued)
Nominal ValueSignal NameRange/StateProbe Locations 
						

							May 25, 20056881096C74-B
4-32Troubleshooting Procedures: Standard Bias Tables
Table 4-19.  Standard Operating Bias: VIP Lines (Dash Configuration)
Nominal ValueSignal NameRange/StateProbe Locations
NA VIP_OUT_1_5v Not accessible J0401-13
NA VIP_OUT_2_5v Not accessible J0401-14
NA VIP_IN_1_5v Not accessible J0401-15
NA VIP_IN_2_5v Not accessible J0401-16
SW_B+ level VIP_OUT_1_12v Deactivate = relay 
closedJ0401-11, J2-18
0.3 V to 0.5 V Activate = relay open
SW_B+ level VIP_OUT_2_12v Deactivate = relay 
closedJ0401-12, J2-19
0.3 V to 0.5 V Activate = relay open
Note: The voltage levels on the microprocessor side are at 2.85 V levels. The microprocessor is 
not designed to drive the relay, but instead, is intended to drive the transistors inside the control 
head or on the interconnect board. Be careful when changing jumpers.
Note: The impedance of the relay is why the SW_B+ does not damage the VIP line. Never connect 
SW_B+ directly to a VIP line.
Table 4-20.  Standard Operating Bias: VIP Lines (Standard Remote Configuration)
Nominal ValueSignal NameRange/StateProbe Locations
VIP_OUT_1_5v Access only by custom 
pin-outJ0401-13
VIP_OUT_2_5v Access only by custom 
pin-outJ0401-14
5 V VIP_IN_1_5v Idle = deactivate = 5 V 
biasJ0401-15
0 V Activate = ground
5 V VIP_IN_2_5v Idle = deactivate = 5 V 
biasJ0401-16
0 V Activate = ground
SW_B+ level VIP_OUT_1_12v Deactivate = relay 
closedJ0401-11, J2-18
0.3 V to 0.5 V Activate = relay open
SW_B+ level VIP_OUT_2_12v Deactivate = relay 
closedJ0401-12, J2-19
0.3 V to 0.5 V Activate = relay open
Note: VIP_IN programmed by CPS. Requires custom pin-out to gain access. 
						

							6881096C74-BMay 25, 2005
Troubleshooting Procedures: Receiver Front-End (RXFE) 4-33
4.11 Receiver Front-End (RXFE)
This section provides band-specific troubleshooting procedures for the receiver front-end.
4.11.1 VHF (136–174 MHz) Band
Use this information, along with the theory of operation, to diagnose and isolate the cause of failures. 
The principle tools needed to troubleshoot a circuit to the component level are the schematic and the 
theory of operation.
In addition to the schematic and theory, you can use the troubleshooting flowcharts in Chapter 5. 
Troubleshooting Charts that will guide you through a sequence of tests and checks designed to 
isolate problems.
Prior to troubleshooting, it is important to review the theory of operation including specific 
precautions and troubleshooting methods. Because much of the radio’s circuitry operates at a high 
frequency, measurements must be taken carefully.
4.11.2 UHF Range 1 (380–470 MHz) Band
Use this information, along with the theory of operation, to diagnose and isolate the cause of failures. 
The principle tools needed to troubleshoot a circuit to the component level are the schematic and the 
theory of operation.
In addition to the schematic and theory, you can use the troubleshooting flowcharts in Chapter 5. 
Troubleshooting Charts that will guide you through a sequence of tests and checks designed to 
isolate problems.
Prior to troubleshooting, it is important to review the theory of operation including specific 
precautions and troubleshooting methods. Because much of the radio’s circuitry operates at 
400 MHz, measurements must be taken carefully.Table 4-21.  Standard Operating Bias: VIP Lines (W3 Remote Configuration)
Nominal ValueSignal NameRange/StateProbe Locations
VIP_OUT_1_5v Access only by custom 
pin-outJ0401-13
VIP_OUT_2_5v Access only by custom 
pin-outJ0401-14
NA VIP_IN_1_5v Not supported with W3 J0401-15
NA VIP_IN_2_5v Not supported with W3 J0401-16
SW_B+ level VIP_OUT_1_12v Deactivate = relay 
closedJ0401-11, J2-18
0.3 V to 0.5 V Activate = relay open
SW_B+ level VIP_OUT_2_12v Deactivate = relay 
closedJ0401-12, J2-19
0.3 V to 0.5 V Activate = relay open
Note: When using the W3 control head and interconnect board, the main board VIP_OUT lines are 
pass-through-only lines. 
						

							May 25, 20056881096C74-B
4-34Troubleshooting Procedures: Power Amplifier Procedures
4.11.3 UHF Range 2 (450–520 MHz) Band
Use this information, along with the theory of operation, to diagnose and isolate the cause of failures. 
The principle tools needed to troubleshoot a circuit to the component level are the schematic and the 
theory of operation.
In addition to the schematic and theory, you can use the troubleshooting flowcharts in Chapter 5. 
Troubleshooting Charts that will guide you through a sequence of tests and checks designed to 
isolate problems.
Prior to troubleshooting, it is important to review the theory of operation including specific 
precautions and troubleshooting methods. Because much of the radio’s circuitry operates at 
400 MHz, measurements must be taken carefully.
4.11.4 700–800 MHz Band
Use this information, along with the theory of operation, to diagnose and isolate the cause of failures. 
The principle tools needed to troubleshoot a circuit to the component level are the schematic and the 
theory of operation.
In addition to the schematic and theory, you can use the troubleshooting flowchart in Chapter 5. 
Troubleshooting Charts that will guide you through a sequence of tests and checks designed to 
isolate problems.
Prior to troubleshooting, it is important to review the theory of operation including specific 
precautions and troubleshooting methods. Because much of the radio’s circuitry operates at 
800 MHz, measurements must be taken carefully.
4.12 Power Amplifier Procedures
This section provides band-specific troubleshooting procedures for the RF power amplifier (RFPA).
4.12.1 VHF (136–174 MHz) Band
Use this information, along with the theory of operation, to diagnose and isolate the cause of failures. 
The principle tools needed to troubleshoot a circuit to the component level are the schematic and the 
theory of operation.
Prior to troubleshooting, be sure to review the theory of operation including any precautions and 
troubleshooting methods.
4.12.1.1 50-Watt Power Amplifiers
In addition to the schematic and theory, this section includes troubleshooting information that will 
help you test and check the circuits to localize and isolate problems.
4.12.1.2 General Troubleshooting and Repair Notes
Most of the common transmitter symptoms are caused by either failure of the power amplifier or a 
failure in the control circuitry. The initial troubleshooting effort should be toward isolating the problem 
to one of those two areas. If either the control voltage or keyed 9.4 V are zero, then the problem is 
likely to be in the control circuit. If those voltages are present, then the problem is more likely in the 
power amplifier circuit.
If for diagnostic reasons, a chip component needs to be removed to facilitate testing, such as a 
series capacitor removed to allow for signal insertion, then the component(s) returned to the circuit 
should be new parts. The application of a soldering iron to many chip components will tend to cause 
leaching which could lead to failure. 
						

							6881096C74-BMay 25, 2005
Troubleshooting Procedures: Power Amplifier Procedures 4-35
After a PA board is replaced, or if any power control circuitry components are replaced, readjust the 
power according to instructions in the ASTRO Digital XTL 5000 VHF/UHF Range 1/UHF Range 2/
700–800 MHz Mobile Radio Basic Service Manual.
NOTE:Due to the high frequency of operation, it is imperative that you use specified Motorola parts 
when component replacement is necessary. At these frequencies, second and third order 
properties of the components are very important and are part of the circuits design. Substitute 
components may not work. It is also critical that you use great care when replacing parts. 
Excessive solder or flux, longer than original leads on coax connectors, misorientation of 
parts, and other commonly benign imperfections may cause the radios performance to 
degrade.
4.12.2 UHF Range 1 (380–470 MHz) Band
In addition to the schematic (“7.3 HUE4039A/HUE4043A (UHF Range 1) Main Board” on page 7-72) 
and theory of operation (“3.6.2 UHF Range 1 (380-470 MHz) Band” on page 3-31), refer to the RFPA 
troubleshooting flowcharts in “5.6.23 No TX Audio (380–470 MHz and 450–520 MHz)” on page 5-37. 
These flowcharts will guide you through a sequence of tests and checks designed to isolate 
problems in the RFPA stages.
See section “4.12.4 700–800 MHz Band” on page 4-35, for more information on troubleshooting the 
RF power amplifier circuitry.
4.12.3 UHF Range 2 (450–520 MHz) Band
In addition to the schematic (“7.4 HUE4040A (UHF Range 2) Main Board” on page 7-132) and 
theory of operation (“3.6.3 UHF Range 2 (450-520 MHz) Band” on page 3-37), refer to the RFPA 
troubleshooting flowcharts in “5.6.23 No TX Audio (380–470 MHz and 450–520 MHz)” on page 5-37. 
These flowcharts will guide you through a sequence of tests and checks designed to isolate 
problems in the RFPA stages.
See section “4.12.4 700–800 MHz Band” on page 4-35, for more information on troubleshooting the 
RF power amplifier circuitry.
4.12.4 700–800 MHz Band
In addition to the schematic (Chapter 7. Schematics, Component Location Diagrams, and Parts 
Lists) and theory of operation (Chapter 3. Theory of Operation), refer to the RFPA troubleshooting 
flowcharts in Chapter 5. Troubleshooting Charts. These flowcharts will guide you through a 
sequence of tests and checks designed to isolate problems in the RFPA stages.
Use the following information as a guide for troubleshooting the RF power amplifier circuitry:
• Read the theory of operation before troubleshooting.
• To avoid damage to the RFPA, only key the transmitter with the main board installed in the 
chassis and the internal screws completely installed and secured with the proper torque setting.
• The chassis eliminator, which allows access to both sides of the main board is useful for 
transmitter troubleshooting. Keying the transmitter for an extended period of time while using 
the chassis eliminator can cause damage to the radio. Therefore, be sure to cool the radio by 
forcing air through the chassis eliminator cooling fins.
• To avoid personal injury from high RF voltages and currents, exercise extreme care while 
troubleshooting the transmitter power amplifier.
• Set the A+ supply to 13.6 V with the current limit set to 15 A.
• Calibrate the power meter regularly using the manufacturers suggested calibration method. 
						

							May 25, 20056881096C74-B
4-36Troubleshooting Procedures: Power Amplifier Procedures
• If a component is removed for troubleshooting, replace the removed part, regardless of its 
condition, with a new part.
• To reinstall the main board into the chassis, follow the reassembly instruction in the ASTRO 
Digital XTL 5000 VHF/UHF Range 1/UHF Range 2/700–800 MHz Mobile Radio Basic Service 
Manual.
• Apply new thermal pads if the current thermal pad are damaged. Follow the instructions in the 
ASTRO Digital XTL 5000 VHF/UHF Range 1/UHF Range 2/700–800 MHz Mobile Radio Basic 
Service Manual.
• Use Motorola-specified parts when component replacement is required.
• When instructed to inspect parts, look for any package damage and/or solder defects.