8/7/2003
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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 EXTERNAL B+ ADJUST (pot R5) in the direction
required to achieve a B+ reading of 13.0 to 13.5 Volts. This voltage should be adjusted with the
TRANSMIT/STANDBY switch in “STANDBY” position.
WARNING
IF THE 15-30 VOLT SUPPLY IS LESS THAN 16 VOLTS, THE EXTERNAL B+ ADJUST SHOULD BE
SET TO 12 VOLTS.
THIS MAY LIMIT THE MAXIMUM OUTPUT POWER.
Frequency Measurement
The RF output frequency of this transmitter should be measured as often as necessary to insure on-frequency
operation and to comply with regulations. Monitor the RF output with a frequency counter via an RF coupler or Watt
meter.
WARNING
NEVER CONNECT THE FREQUENCY COUNTER DIRECTLY TO THE RF OUTPUT CONNECTOR
OF THE SRPT-30/40A.
THE FREQUENCY COUNTER SHOULD BE COUPLED OFF OF AN RF COUPLER OR A WATT
METER.
EXCEEDING THE INPUT POWER RATING OF THE FREQUENCY COUNTER COULD DO
INTERNAL DAMAGE TO IT.
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