Data Sheet Chapter 5

4-6 kW UHF Translator Chapter 5, Detailed Alignment Procedures
837B, Rev. 0 5-11
control); adjust R87, the manual gain
pot, to mid-range.
• IF phase corrector board – Move
jumper W2 on J9 to the phase
correction enable position; move the
jumper W3 on J10 to the amplitude
correction disable position.
2. The combined IF output of the sync
tip clamp modulator board is cabled
to jack J32 of the ALC board.
Remove J32 from the board and
check to see that DS1, Input Fault,
is illuminated. Reconnect J32 and
check to see that DS1 is
extinguished.
3. Jumper W3 on J6 should be in the
manual position; monitor jack J3
with a spectrum analyzer.
4. With a multiburst video signal
present, tune C4 for a flat-
frequency response of ±0.5 dB.
5. Before proceeding with part 2 of the
ALC board alignment (described in
section 5.1.10), check the IF phase
corrector board to make sure that it
is functioning properly.
5.3.8 (A9) IF Phase Corrector Board
(1227-1250; Appendix D)
Refer to the system alignment
procedures at the end of this chapter for
the set up of (A9) the IF phase corrector
board in the exciter tray. The signal level
into the board should be approximately
the same as the output of the board.
The IF input jack of the IF phase
corrector board is fed from J3, the IF
output jack of (A8) the ALC board.
The IF output jack of the IF phase
corrector board is fed to J7, the IF input
jack of (A8) the ALC board.
5.3.9 (A8) ALC Board, NTSC (1265-
1305; Appendix D) (Part 2 of 2)
Input a multiburst video test signal at the
baseband video input. Connect a
spectrum analyzer to J11. Tune C63 for a
flat-frequency response of ±0.5 dB.
Move the Operate/Standby switch on the
front panel of the translator to the
Operate position.
Place jumper W3 on jack J6 in the
Manual mode and adjust R87 for 0.8
volts at TP4.
Place jumper W3 on J6 in the Auto mode
and adjust the front panel power adjust
control A20 fully CW. If the optional
remote power raise/lower kit is present,
adjust switch S1 on the board to
maximum voltage at TP4. Adjust R74,
the range adjust, for 1 volt at TP4.
Adjust the front panel power adjust
control (A20) for 0.8 VDC at TP4. If the
optional remote power raise/lower kit is
present, adjust switch S1 on the board to
the mid-range of its travel and then
adjust the front panel Power Adjust
control (A20) for 0.8 VDC at TP4.
Disconnect the plug that is now on J12
(IF output) and monitor the output with a
spectrum analyzer. The output should be
approximately 0 dBm. Adjust R99, if
necessary, to increase the output level. If
a smaller output level is needed, move
the jumpers J27 and J28 to pins 2 and 3
and adjust R99 as needed. Reconnect
J12.
Move W2 on J5 to the cutback enable
position. Remove the input video signal
and verify that the output of the
translator drops to 25%. Adjust R71, the
cutback level, if necessary. Restore the
video input signal.
Note: This step affects the response
of the entire translator. Connect a
video sweep signal to the input of
the tray. Monitor the output of the
system with a spectrum analyzer.
Adjust C71 with R103 and C72 with
R106, as needed, to flatten the
response. C71 and C72 can be