System Description

835A 4 kW, 5 kW or 6 kW UHF Transmitter System Description
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the UHF Amplifier Trays.
Control and Status - Continued
When the UHF Exciter is in Operate, the Green LED (DS2) is On and when in Standby the Amber LED (DS1) is On. Note: If
the Transmitter does not switch to Operate when S1 is switched to Operate, check that a dummy plug, with a Jumper between
Pins 1 & 2, is connected to Jack J7 located on (A9) the Remote Interface Assembly in the Single UHF Exciter Assembly. This
Jumper provides the Interlock needed for the operation of the Transmitter. If the Interlock is present, the Green LED (DS5),
located on the Transmitter Control Board, should be lit.
Operation of the Transmitter is controlled by the front panel switches located on the UHF Exciter Tray. During Normal
operation of the Transmitter, Switch S2 should be in the Auto position. The front panel of the UHF Exciter also has LEDs that
indicate a Video Fault (Loss), Red LED (DS9) and a VSWR Cutback, Amber LED (DS7).
Baseband Input and Remote Connections
The Baseband Video and Audio Inputs to the Transmitter, connect to the (A9) Remote Interface Panel located on the rear of
the Single UHF Exciter Assembly. The Baseband Video Input connects to Jack J2, which is loop-thru connected to J1, that is
wired to J1 on the Exciter. The Baseband Audio Input connects to Terminal Block TB1 for Balanced Audio or to Jack J6,
which is loop-thru connected to J13, that is wired to J3 on the Exciter, for Composite, Stereo, Audio.
Remote Monitoring and Operation of the Transmitter is provided through the Jacks (J8, J9 & J10) located on (A9) the Remote
Interface Assembly located on the rear of the Single UHF Exciter Assembly. Jack (J7) should have a dummy plug connected
to it, which has a jumper connected between Pins 1 & 2, that provides the Interlock to the Exciter needed to operate the
Transmitter. If the Jumper is missing, the Transmitter will not switch to Operate. If remote connections are made to the
Transmitter they should be made through the plugs provided in the Installation Material as noted on the Interconnect Drawing
(1278-8400) for the Single UHF Exciter. The On Channel RF Input to the Receiver Tray connects to the Transmitter through
(A9) the Remote Interface Assembly at J1, "N" type connector, for 50Ω Input or J3, "F" type connector, for 75Ω Input.
Main AC Input
The Transmitter needs an AC input of 208/240 VAC 55 Amps for 3 Phase or 100 Amps for Single Phase for each Amplifier
Assembly and 20 Amps Single Phase for the Single Exciter Assembly.
The 208/240 VAC Input to each Amplifier Assembly connects to (A10) the AC Distribution Assembly located on the right
side, center rear of the Cabinet. The Assembly contains the Terminal Block (TB1) to which the 208/240 Three Phase or Single
Phase connects. For 3 Phase: Line 1 to TB1-1A, Line 2 to TB1-2A, Line 3 to TB1-3A and Safety Ground to TB1-4A. For
Single Phase: Line 1 to TB1-1A, Line 2 to TB1-3A and Safety Ground to TB1-4A The AC Distribution Panel contains six
Circuit Breakers that supply the AC to the rest of the Amplifier Assembly. The Input AC from TB1B is connected to (CB1)
the Main AC Circuit Breaker (55 Amps for 3 Phase or 100 Amps for Single Phase) which distributes the 208/240 VAC to the
other circuit breakers. The output of CB1 has six MOVs, VR1, VR2, VR3, VR4, VR5 and VR6 mounted to it. VR4, VR5,
and VR6 are connected from. the AC Lines to Ground and VR1, VR2, and VR3 are connected across the AC Lines. The
switched Input AC is wired through the five Circuit Breakers, CB2-CB6, via AC Line Cords to the five UHF Amplifier Trays
mounted in each Amplifier Array Cabinet. CB2 is a 20 Amp Circuit Breaker which supplies the AC voltage to the (A1) UHF
Amplifier Tray. CB3 is a 20 Amp Circuit Breaker which supplies the AC voltage to the (A2) UHF Amplifier Tray. CB4 is a
20 Amp Circuit Breaker which supplies the AC voltage to the (A3) UHF Amplifier Tray. CB5 is a 20 Amp Circuit Breaker
which supplies the AC voltage to the (A4) UHF Amplifier Tray. CB6 is a 20 Amp Circuit Breaker which supplies the AC
voltage to the (A5) UHF Amplifier Tray. CB7 is used in the 6 kW Transmitter and supplies AC to the (A6) UHF Amplifier
Tray . The circuit breakers CB8 and CB9 are not used in the 2 kW Amplifier Array Assemblies. These circuit breakers
control the AC to the A12-A3 and A12-A5 Fans mounted on the (Optional) (A12) Reject Load Assembly which are part of the
2.5 and 3 kW Amplifier Array Assemblies.