User's Manual

1 1 7 B 2 0 W a t t VHF High Band Transla t or Upconve rt er/ Am plifie r Tray
Circuit Descript ion
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Also located on the front panel of the Tray is ( CB1) t he 7.5 Am p On/ Off Circuit Breaker, which
dist ributes AC to the t w o power supplies, t he ± 12 VDC and t he + 26 VDC, that are part of the
Tray. The Front Panel Met er ( A27) is able t o be switched by S1 to read the % Visual Output
Power, % Aural Out put Power, % Visual + Aural Reflect ed Power, the Swit ching Power Supply
Voltage, the ALC Reference Voltage or the AGC Det ect or Voltage.
A Front Panel Gain Control ( R2) provides an ALC adj ust which sets t he Out put Power level of the
Transm it t er.
The AC needed to operat e the Tray connect s t o the I EC Connect or ( A1) located on t he rear panel.
The I EC Connect or cont ains a 10 Am p over- current protect ion Fuse F1. The AC connect s t o TB1
which has jum pers for 115 or 230 VAC operat ion and MOV devices connect ed across t he lines for
surge and spike prot ect ion. The circuit breaker ( CB1), which lights when switched on and AC is
present t o the Tray, controls t he I nput AC that connects t o TB1. When CB1 is switched On the
input AC connects t o ( A5) t he step down Toroid for the ± 12 VDC Power Supply. The AC is also
connect ed t o t he cont act s of the I solation Relay ( A2). The I solation Relay cont rols t he AC
Voltage t hat is supplied to t he Switching Power Supply which is needed for operation. The
I solat ion Relay is energized by a Relay Enable Com m and from t he Transm it t er Control Board and
occurs w hen the System is switched t o Operate and there is no Therm al Fault present . The
Transm it t er Control Board rem oves the Relay Enable Com m and t o t he I solat ion Relay in the event
of excessive t em perature sensed by the Therm al Swit ch (A17- A3) m ounted to t he Am plifier
Heatsink Assem bly. The de- energized I solat ion Relay rem oves the AC I nput to t he Swit ching
Power Supply, which shuts down t he pow er supply.
POWER SUPPLI ES
There are t w o power supplies in the Tray which provide the needed ± 12 VDC and t he + 26 VDC for
the operat ion of the Tray and the Am plifier Boards. The ± 12 Volt Power Supply is com prised of
( A5) an AC St ep-Down Toroid and (A6) a + 12V( 3A) / - 12V Power Supply Board ( 1092-1206) . The
+ 12V( 3A) / - 12V Power Supply Board cont ains t wo full wave bridge rect ifier net works, one for + 12
VDC and one for - 12 VDC. The board cont ains t hree nonadj ust able regulat or I C circuit s wit h short
circuit protect ion (U1, U2 & U3) for + 12 VDC and one nonadjust able regulat or I C circuit wit h short
circuit protect ion (U4) for - 12 VDC. The second power supply in the Tray is a + 26 Volt Switching
Power Supply Assem bly ( V250D04) that provides the + 26 VDC t o ( A17- A1) the VHF High Band
Driver Board and ( A17- A2) t he VHF High Band Am plifier Board.