Alignment; Pll & Transmitter; Pll Vcv; Figure 5-1. Af Test Adapter Schematics - Motorola PM1200 Basic Service Manual

Radio Alignment and Programming Procedures: Alignment
Because of the bridge audio amplifier circuit used in the radio, it is necessary to construct and use a
simple audio load test adapter as shown in the schematic diagram above, when conducting receiver
alignment steps.
To 20-pin
accesories
connector
5.4

Alignment

Channel
CH1
CH2
CH3
CH4
CH5
5.4.1 PLL & Transmitter
• Set up the test equipment as shown on
• Maintain the supply voltage at 13.4 V DC for all steps.
5.4.2

PLL VCV

1. Connect the positive lead of the DC voltmeter to the test point TP1010 (VCV) on the Main
Unit, and the negative lead to chassis ground.
2. Set the transceiver to the high band edge frequency channel, then adjust trimmer-capacitor
T1005 on the Unit for 7.0 V on the voltmeter.
3. Key the transmitter, and adjust trimmer-capacitor T1006 on the Unit for 7.0 V on the
voltmeter.
4. Next select to the low edge frequency channel and confirm about 1.8 V (1.5 V to 2.1 V) on the
voltmeter.
5. Key the transmitter, and confirm about 1.8 V (1.5 V to 2.1 V) on the voltmeter.
6880309U09-A
2Ω
10W
2 Ω
10W
(4 Ω Dummy Load)

Figure 5-1. AF Test Adapter Schematics

Table 5-1. Alignment Channel Frequencies

Frequency (MHz)
(Simplex)
29.71/ 37.01
33.35/ 43.01
36.99/ 49.99
33.35/ 43.01
33.35/ 43.01
Figure 5-2 on page 5-5
Attenuated
Test Output
To the input of the
audio analyzer
GND
CTCSS DCS
Encode Encode
None None
None None
None None
151.4 Hz None
None 023
for transmitter alignment.
October 26, 2007
5-3