User's Manual

Innovator CHV400BTD ATSC Transmitter Board Descriptions
Technical Manual, Rev. 0 62
board. The +42VDC input at the TB8 input senses the current to the (A3) 878 output
amplifier pallet through TB7 on the board. The +42VDC input at the TB10 input senses
the current to the (A4) 878 output amplifier pallet through TB9 on the board.
The two or four sensing circuits are identical therefore only one will be described. For
the (A1) 878 amplifier pallet, the +42VDC from the (A8) switching power supply
connects to TB2. R1 and R2 are the parallel .01Ω current sensing resistors which
supplies the voltage values to the U1 current sense amplifier IC. R11 is a gain adjust,
which is adjusted to eliminate any rSense Error and to place the OpAmp output at 2.61V
for 40Amps sense as measured at TP3. The current sense output at J1-1 connects to
the (A7) control board for metering purposes.
(A5) 2 Way Splitter Board (1313941), in CHV400B
The 2 way splitter board takes the RF Input at J1 (≈12.5 Watts ATSC) on the board and
splits it into two equal outputs (≈5Watts ATSC) that connect to the inputs of the two
amplifier pallets at J1.
(A2 & A3) 500 Watt Amplifier Pallets (1313581)
There are two 500 Watt Amplifier Pallets mounted on the Amplifier Heatsink Assembly.
Each of the amplifier pallets has approximately +25dB of gain for the VHF HB frequency
range of 170 to 230 MHz. The pallets operate Class AB and generate 200 Watts ATSC
with an input of 1 Watt ATSC.
(A6) 2 Way Combiner Board (1313969), in CHV400B
The 2 way combiner board takes the two RF Inputs at J4 & J5 (≈200Watts ATSC) on the
board and combines them to a single output (≈400Watts) at J1 that connects to J2 the
7/16” (1.1cm) Din RF output jack of the tray.
(A8 & A9) CHV400B, 500 Watt, 750 Watt and 1000 Watt Amplifier Tray Power
Supplies
The 230VAC, needed to operate the tray, connects through the AC power cord at J3, the
power entry module located on the rear panel of the tray. The AC lines are connected to
a terminal block TB1 to which the circuit breaker(s) connect. There are two On/Off
20A/250VAC circuit breakers that are mounted on the back panel of the tray on either
side of J3 the AC input jack. NOTE: In CHV400B Amplifier tray there is one circuit
breaker. With the circuit breaker(s) switched On, the AC is distributed to the one (A8)
or two (A8 and A9) DC power supplies. In a standard CHV400B amplifier tray one 20
Amp circuit breaker CB1 connects the AC to the (A8) DC power supply. In all power
amplifier trays, TB1 has three varistors (VR1-VR3) connected across the AC input lines
for surge and over voltage protection. The AC input connected to TB1 is wired to 2 amp
fuses that is connected to the two fans (A11 & A12) mounted on the rear panel of the
tray. Both fans will run immediately when AC is applied to the tray.
The +5VDC for the operation of the amplifier control board in the tray is generated by
the (A8) or both the (A8 & A9) power supplies at J1-9 on each power supply. The
+5VDC from the (A8) power supply connects to J4-8 and the +5VDC from the (A9)
power supply connects to J5-8 on the control board. The +5VDC is produced when AC is