Vco Hybrid Assembly; Table 4-3. Test Mode Channels; Table 4-4. Vco Frequency And Switching Logic - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

4-6
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.
addition,
MODE
CHAN 1
CHAN 2
CHAN 3
CHAN 4
CHAN 5
CHAN 6
CHAN 7
CHAN 8
CHAN 9
CHAN 10
MODE
3. Continue troubleshooting by using the Fail 001 troubleshooting chart in Chapter 5.
4.6.2

VCO Hybrid Assembly

The VCO hybrid substrate is glued to the carrier board. The hybrid is not a field-repairable assembly.
If a failure is indicated in this assembly, replace the entire carrier board.
May 25, 2005
Troubleshooting Procedures: VHF (136–174 MHz) Band Main Board Troubleshooting
Table 4-3 indicates the frequency and Aux logic level for each test mode channel. In
Table 4-4 provides information about the frequency of operation for each VCO.

Table 4-3. Test Mode Channels

Test LV Frac-N
TX Logic
AUX 2
AUX 2
AUX 2
AUX 2
AUX 2
AUX 1
AUX 1
AUX 1
AUX 1
AUX 1

Table 4-4. VCO Frequency and Switching Logic

Frequency
(MHz)
RX 245.65–
264.65
RX 264.65–
283.65
TX 155–174
TX 136–155
TX Freq LV Frac-N
MHz RX Logic
136.0125 AUX 3
140.7625 AUX 3
145.5125 AUX 3
150.2625 AUX 3
154.9875 AUX 3
155.0125 AUX 4
159.7625 AUX 4
164.5125 AUX 4
169.2625 AUX 4
173.9875 AUX 4
AUX1 AUX2 AUX3
LOW LOW HIGH
LOW LOW LOW
HIGH LOW LOW
LOW HIGH LOW
RX Freq
MHz
245.7125
250.4625
255.2125
259.9625
264.5875
264.7125
269.4625
274.2125
278.9625
283.5875
AUX4
LOW
HIGH
LOW
LOW
6881096C74-B