Maintenance—492/492P Service Vol. 1 (SN B030000 & up)
-D -fl__ 5 m
I . A
y v
Fig. 4-15. Filter tune tabs in the 829 MHz converter.
j. Repeat the procedure for the final (fourth) resonator
for a response similar to that shown in Fig. 4-17B.
k. Check that the return loss is equal to or greater than
12 dB.
I.
Disconnect the return loss Device Under Test lead to
the Peltola jack J1029 on the 829 MHz Amplifier board, then
unsolder and reconnect the jumper to the amplifier output.
m. Replace the 829 MHz Converter cover and reinstall
the assembly in the 492/492P.
Troubleshooting and Calibrating the 2182 MHz
Phaselocked 2nd LO
The assembly contains a microstrip phaselocked
2182 MHz oscillator and its phaselocking circuits. The 14-
22 MHz Phaselock board is contained in the mu-metal hous
ing; the 2182 MHz Oscillator, 2200 MHz Reference, and
2200 MHz Reference Mixer are contained in the machined
aluminum housing.
The 2182 MHz Microstrip Oscillator and the 2200 MHz
Reference Mixer contain critical length printed elements.
When damaged, these elements are difficult to repair; there
fore, the board should be replaced. If either the varactor
REV JUN 1983
4-25
