User Manual

37
TUNE-UP AND ADJUSTMENTS
Refer to Location of Adjustments Drawing No. 702-120 and appropriate schematic
diagrams for each module.
This equipment was thoroughly tested and inspected at the factory prior to shipment. The actual
equipment performance was recorded on the SRPT-30/40A TRANSMITTER FACTORY TEST
REPORT. Adjustments should rarely be necessary in the field and should be attempted only by
highly trained technicians familiar with this type of equipment. Laboratory grade test equipment is
required and is listed under TEST EQUIPMENT AND TOOLS. For location of adjustments and test
points in the SRPT-30/40A Transmitter refer to Adjustment Location Diagram, 702-120.
NOTE
FOR ALL ADJUSTMENTS, REMOVE THE TOP COVER FROM THE SRPT-30/40A CHASSIS.
REPLACE THE COVER WHEN THE ADJUSTMENT PROCEDURE IS COMPLETE.
Switching Power Supply Voltage Adjustment
The input to the switching power supply can be from 110-120 or 220-240 VAC, 50/60 Hz. The DC B+ output,
measured off of one of the red wires of the switching supply, can be slightly adjusted at B+ ADJUST. The recommended
B+ reading should be 14.5 volts.
B+ Adjustment When Using 15-30VDC External Supply
CAUTION
THIS ADJUSTMENT HAS BEEN SET AT THE FACTORY AND SHOULD NOT REQUIRE ANY
FURTHER ADJUSTMENTS.
1. Remove AC line voltage from SRPT-30/40A.
2. Connect up external supply to the 15-30VDC pins of the AUXILLARY connector (see the ACCESSORY Input
Connector paragraph in the CONTROL & CONNECTOR FUNCTIONS section).
3. Switch the AC LINE front panel switch to the “OFF” position.
4. Turn on external supply and adjust to approximately 18 VDC.
5. Using a VOLT METER, with negative lead connected to ground (chassis), connect the positive lead to one of the
red wires connected to the 800-379AR I/O board.
6. On the TWO-STAGE RF POWER AMPLIFIER board adjust B+ ADJUST (pot R5) in the direction required to
achieve a B+ reading of 13.5 to 14.5 Volts. This voltage should be adjusted with the TRANSMIT/STANDBY
switch in “STANDBY” position.