Broadcast Electronics FM-5T, User Manual, Page: 157 / 191

2-2
WARNING: DISCONNECT POWER PRIOR TO SERVICING
2-13. Apply power to the transmitter.
2-14. Refer to Figure 2-1 and select VSWR OVERLOAD as follows:
1. Operate customer adjustment function switch SW1 to position 6.
2. Depress and hold customer adjustment up/down switch S2 in the up position
to raise the threshold.
2-15. Disconnect cable 131 from the reflected power directional coupler (
↓
port) on the transmit
ter low-pass filter.
2-16. Using the nut-driver, loosen the clamps securing the reflected power directional coupler to
to the low-pass filter.
2-17. Rotate the reflected power directional coupler 180 degrees so the arrow on the coupler is up
(
↑
). Secure the clamps.
2-18. Connect the 7 dB attenuator to the reflected power directional coupler and connect cable
131 to the attenuator.
2-19. Apply power and operate the transmitter at the normal RF power output as indicated by
the front panel OUTPUT POWER meter.
2-20. Depress the VSWR switch/indicator to illuminate the switch/indicator.
2-21. Refer to Figure 2-1 and use up/down switch S2 to lower the VSWR overload threshold un
til the VSWR OVERLOAD indicator and the OVERLOAD RESET switch/indicator illu
minate and the transmitter cycles off.
2-22. Depress the HIGH VOLTAGE OFF switch then depress the LOWER switch/indicator for
approximately 4 seconds to lower the transmitter power.
2-23. Depress the OVERLOAD RESET and the HIGH VOLTAGE ON switch/indicators.
2-24. Depress the RAISE switch/indicator to raise power. The transmitter will cycle off at a
VSWR indication of 2.8 : 1. If not, repeat the adjustment.
WARNING
WARNING
DISCONNECT ALL TRANSMITTER PRIMARY POWER
BEFORE PROCEEDING.
2-25. Disconnect all transmitter primary power.
2-26. Remove the test equipment and replace the reflected power directional coupler. Ensure the
reflected power directional coupler arrow is down ( ↓ ). Ensure cable 131 is re-connected to
the reflected power directional coupler port.
2-27.
PLATE OVERLOAD ADJUSTMENT.
The plate overload control can be adjusted from 0.1 A
to 0.75 A above a normal plate current level. The factory default is 0.2 A. To adjust the
PLATE overload threshold, proceed as follows.