Assembly Instructions Chapter 4

4-6 kW UHF Translator Chapter 4, Circuit Descriptions
837B, Rev. 0 4-36
by capacitor C4 and bypassed by C5 to
prevent oscillations. The filtered -12
VDC is applied to U2 a 7912 IC voltage
regulator and current limiter. C6 is a
bypass capacitor to prevent oscillations
in the output DC lines. C7 is a holding
capacitor to maintain -12VDC for an
instance even if the supply is lost. This
is to allow the positive voltages to be
removed from the Amplifier devices to
prevent damage to the devices. DS2 is
a Green LED which when lit indicates
that the -12 VDC is present at the
output of the board. The -12VDC is
distributed to the rest of the Boards in
the Tray thru Pins 4 & 5 of each of the
Output Jacks, J1, J2, J3 & J4.
The ±12 VDC outputs of the board are
connected to the rest of the boards in
the Metering Panel.
4.5 (A8) AC Distribution Assembly
(1245-1500; Appendix C)
The AC Distribution Assembly
distributes the Main AC Input, 208/240
VAC @ 20 Amps, that connects to the
UHF Exciter Assembly Cabinet to the
Trays and Assemblies which make up
the Exciter.
The 208/240 VAC Main AC Input to the
Exciter Cabinet connects to the
Terminal Block TB1, Line 1 to TB1-1A,
Line 2 to TB1-3A and Ground to TB1-
2A.
The 208/240 VAC Main AC Input
connects from the Terminal Block TB1-
1B (Line 1) to the 20 Amp Circuit
Breaker CB1-1, TB1-2B (Ground) to
Chassis Ground & TB1-3B (Line 2) to
the Circuit Breaker CB1-3. Three
MOVs, for surge and transient
protection, are connected to the AC
Lines from the Circuit Breaker, VR1
from Line 1 to Ground, VR3 from Line 2
to Ground and VR2 across the AC Lines.
The switched 208/240 VAC Main AC
Input is wired from the Circuit Breaker
Terminal 2 to the L inputs and Terminal
4 to the N Inputs of the (A1 & A2) IEC
Outlet Strips. The E Inputs to both IEC
Outlet Strips connect to Chassis
Ground.
There are four outputs for both the
(A1) and the (A2) IEC Outlet Strips.
On the A1 Outlet Strip, J1 connects to
J14 on the (A1) Exciter #1, J2 connects
to J14 on the (Optional) (A2) Exciter
#1, J3 connects to J8 on the (Optional)
(A3) Exciter Switcher Tray and J4
connects to J2 on the (A4) Variable
Phase/Gain Tray. On the A2 Outlet
Strip, J5 connects to J2 on the (A5)
Variable Phase/Gain Tray, J6 connects
to J8 on the (A6) Metering Panel, J7
connects to J2 on the (A7) Receiver
Tray or to the AC Input Jack on the
(Optional) Digital Modulator and J8 is
not used in this System.
4.6 (A2 & A3) 2-3 kW Amplifier
Arrays (1278-1300; Appendix C)
There are two Amplifier Array
Assemblies in the 837B 4-6 kW UHF
Solid State Internally Diplexed
Television Translator. The (A2 & A3)
Amplifier Array Assemblies (1278-
1300) are identical. Each Amplifier
Array contains; (A9-A1) an 8 Way
Splitter (ZFSC-8-43), (A1 thru A4,
A5(5kW) and A6(6kW)) UHF Amplifier
Trays, (A7) a 4, 5 or 6 Way Combiner,
(A12) a Reject Load Assembly (Only
with 5 & 6 kW transmiters), (A8) an
Output Coupler, (A10) an AC
Distribution Assembly (1278-1100
three phase or 1278-1200 single
phase) and (A11) an Interface Panel.
The output of the (A4) Variable
Phase/Gain Tray, located in the Exciter
Assembly, connects to (A2) the Side A
Amplifier Assembly. The output of the
(A5) Variable Phase/Gain Tray connects
to (A3) the Side B Amplifier Assembly.
The RF Input (+16 dBm) from the
Variable Phase/Gain Tray connects to
the RF Input Jack J1 on (A11) the