Table 4-10. Test Mode Channels Uhf Range 2 (Aux 4 Is Not Used For Vco Selection In Uhf) - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

Troubleshooting Procedures: UHF Range 2 (450–520 MHz) Band Main Board Troubleshooting
4.8 UHF Range 2 (450–520 MHz) Band Main Board Troubleshooting
This information will help you troubleshoot the RF section of the UHF Range 2 (450–520 MHz) band
XTL 5000 radio. Use this information, along with the theory of operation and troubleshooting charts,
to diagnose and isolate the cause of failures.
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 high
frequencies, measurements must be taken very carefully. Notes and cautions are added to the text
to alert you to this need in areas of greatest sensitivity. However, the need for extreme care does
exist in all measurements and tests.
4.8.1 Display Flashes "FAIL 001"
This display indicates a synthesizer "out-of-lock" condition. The following information will help to
trouble shoot the frequency generation unit to the component level. Perform the following checks to
determine the mode of the Fail 001:
1. Determine if the "out-of-lock" condition occurs in either receive mode, transmit mode, or both.
Also, check other frequencies programmed in the unit if available.
2. To determine if the "out-of-lock" is frequency or VCO dependant, place the unit into RF TEST
Mode, as described in the ASTRO Digital XTL 5000 VHF/UHF Range 1/UHF Range 2/700–
800 MHz Mobile Radio Basic Service Manual (6881096C73) and step through each test
channel.
In addition,
each VCO.

Table 4-10. Test Mode Channels UHF Range 2 (AUX 4 is not used for VCO selection in UHF)

AUX (TX Logic)
Test
Mode
1 2
1 0
Chan 1
1 0
Chan 2
Chan 3 1 0
Chan 4 1 0
1 0
Chan 5
Chan 6 0 0
Chan 7 0 0
Chan 8 0 0
0 0
Chan 9
0 0
Chan 10
6881096C74-B
Table 4-10 indicates the frequency and Aux logic level for each test mode channel.
Table 4-11 on page 4-18
TX TX Freq
VCO
(MHz)
3
0
Q5826 450.025
0
Q5826 455.825
0 Q5826 463.675
0 Q5826 473.375
0
Q5826 484.975
0 Q5825 485.025
0 Q5825 490.825
0 Q5825 496.625
0
Q5825 508.375
0
Q5825 519.975
provides information about the frequency of operation for
AUX (RX Logic)
1 2 3
0 0 1 Q5905
0 0 1 Q5905
0 0 1 Q5905
1 1 0 Q5903
1 1 0 Q5903
1 1 0 Q5903
1 1 0 Q5903
0 1 0 Q5901
0 1 0 Q5901
0 1 0 Q5901
RX VCO
RX RX Freq
Freq
VCO
(MHz)
(MHz)
450.075 559.725
455.625 565.275
463.625 573.275
473.325 582.975
484.925 594.575
485.075 594.725
490.875 600.525
496.675 606.325
508.325 617.975
519.925 629.575
May 25, 2005
4-17