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Several tests are presented which will help isolate a pos- sible RF or control circuit problem. The control circuits, which are located on the T/R Board, contain no adjustments and there is no alignment required for the control circuits. See the Trou- bleshooting section for test information if a problem is sus- pected in the control circuits.
TEST EQUIPMENT
General Equipment
1. | RF Generator |
2. | Wattmeter (5 watts) |
3. | Ammeter (2 amperes) |
4. | Distortion Analyzer |
5. | Frequency Counter |
Special Equipment
1.IBM Compatible Computer with
2.Interface Box 19D438367G1
3.
4.Programming Cable
5.Programming Software
6.Synthesizer Extender Cable
7.Discharge Analyzer
8.Alignment Tool, 0.1" slotted (metal) tips
9.Alignment Tool, 0.1" slotted tips.
TEST SET UP
Connect the leads of the dummy battery to the two battery terminals accessble in the open radio. The external power leads from the dummy battery will be connected later. Connect the
For programming, the
Set the DC power supply to 7.5 volts(±0.1 volts) for a 2 watt radio, or 10 volts (±0.1 volts) for a 4 watt radio. Connect the power supply to the dummy battery as shown in Figure 3.
1.With the highest transmitter frequency selected, tune C118, C124, C126 for maximum output power meas- ured with the Power Meter. The power out should be greater than 4.5 watts with 10V supply and greater than 2.5 watts with 7.5V supply.
2.Adjust C126 for minimum DC current drain from the power supply until the power output is
3.Adjust C118 for minimum DC current drain from the power supply until the power output is
4.Tune C124 for maximum outut power.
5.Return C126 for 1050 mA (±10 mA) for 10V sup- plies and 750 mA (±10 mA) for 7.5V supplies. Check the output power. The output power should be equal to or greater than the minimum power as listed in the table above.
S E R V I C E
6. | Test Box |
7. | Test Cable 19C851752P8 |
To gain access to adjustable circuit components for align- ment of the radio, the front cover must be removed as described in the Disassembly Section. A test setup should be arranged as shown in Figure 3.
TRANSMITTER ALIGNMENT
With the test setup for transmitter operation in place, select the highest transmit frequency and key the radio ON to find an indication of output power on the power meter. See Figure 4 for the location of tuning controls and test points.
Frequency Set
Measure the frequency of the RF output signal with the frequency meter. It should be within ±100 Hz of the pro- grammed frequency. Should a small adjustment be neces- sary, this change can be made by tuning the Reference Oscillator (TCXO) module U203 on the Synthesizer Board.
Set Transmitter Power
The following sequence should be followed for maxi- mizing rated output power:
Table 1 - Minimum Output Power
| 2 WATT | 4 WATT |
| RADIOS | RADIOS |
Battery or Supply | 7.5 | 10 |
Voltage | VOLTS | VOLTS |
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Minimum Output | 1.9 | 3.8 |
Power | WATTS | WATTS |
Customer Programming And Wide Band Tuning
This section describes the programming and adjust- ments for wide band tuning. The following steps
–Up to 10 MHz spread with no degradation from Pref
–Up to 17 MHz spread with less than 1 dB of degra- dation from Pref in the
or
–Up to 24 MHz spread with less than 1 dB of degra- dation from Pref in the
1.Frequency spreads greater than 10 MHz only - Program the radio on a channel mid way between the two desired frequencies. Tune the radio by following Steps
Frequency spreads less than or equal to 10 MHz only
S
E C T I O N
Figure 3 - Test Setup
3