User Manual
41
Modulation Adjustment
1. Connect a modulation (or deviation) meter to the output of the SRPT-30/40A.
WARNING
NEVER CONNECT THE MODULATION METER DIRECTLY TO THE RF OUTPUT CONNECTOR OF
THE SRPT-30/40A.
THE MODULATION METER SHOULD BE COUPLED OFF OF AN RF COUPLER OR A WATT
METER.
EXCEEDING THE INPUT POWER RATING OF THE MODULATION METER COULD DO
INTERNAL DAMAGE TO IT.
2. Remove the TRANSMITTER SYNTHESIZER cover.
3. Inject a tone into the transmitter at maximum audio modulation (in most cases this is 7.5 KHz) at 3 dB compression.
4. Adjust pot R63 on the TRANSMITTER SYNTHESIZER while viewing the modulation meter. Turning the pot
clockwise to increase modulation and turn it counter-clockwise to decrease it.
WARNING
INCREASING THE MODULATION WILL INCREASE THE TRANSMITTER BANDWIDTH!
5. Replace the TRANSMITTER SYNTHESIZER cover.
Procedure for Removing Pre-Amp Mixer Board, 800-251
1. Remove knobs and hardware from four level control pots on front panel.
2. Notice the Neutrik mic. Connector has a small hole near the center in addition to the three pin receptacles. This hole
contains a tiny locking mechanism. Using a small (0.75” wide) flat blade screwdriver, insert tool into hole and turn
slowly until screwdriver engages connector lock. Use care!
3. Turn screwdriver counter-clockwise (1/8 turn) until mic. Insert releases.
4. After following the above procedure on each input, gently push the black plastic inserts out of the metal shells while
simultaneously pushing the gain adjust pots inward until the board releases from the front panel.
5. Remove board from the chassis and service. To re-install board reverse the above procedure. Be careful! The
locking mechanism is delicate.
Forward Power Calibration – SRPT-40A Only
Note: The SRPT-30 Forward Power Calibration can only be performed at the factory.
CAUTION
THIS ADJUSTMENT HAS BEEN SET AT THE FACTORY AND SHOULD NOT REQUIRE ANY
FURTHER ADJUSTMENTS.