Motorola 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...

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...

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...

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...

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...

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...

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,...

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...

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...

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...