TM11-5895-846-14
After replacement, proceed to paragraph 5-24 below and
(2) Place the IF IN switch in the 700 MHz
perform the gain adjustments.
position and observe the MONITOR meter for an
(10) Place the MONITOR switch to the IPA IN
indication of 15 to 35. If the indication is correct, proceed
position and observe the MONITOR meter for an
to step (7) below. If the indication is incorrect, proceed
indication of 5 to 45. If the indication is correct, proceed
to step (3) below.
to step (12) below. If the indication is incorrect, proceed
(3) Disconnect the modem drive cable from
to step (11) below.
the 700 MHz IF connector on the front panel.
(11) Place and momentarily hold the APC
(4) Place and momentarily hold the TEST
switch on the SHF filter/detector module A5 in the test
OSC switch in the ON position. Observe the monitor
position. Observe the MONITOR meter. If the indication
meter for an IF IN indication.
is correct, proceed to step (12) below. If indication is
(5) If an IF IN is indicated, the problem is very
incorrect, remove and replace the SHF upconverter
likely inadequate 700 MHz drive from the modem.
module A4. After replacement, proceed to paragraph 5-
Replace the drive cable back on the 700 IF IN connector.
24 below and perform the gain adjustments.
No further testing necessary.
(12) Place the monitor switch to the IPA out
(6) If no IF IN is indicated, remove and
position and observe the monitor meter for an indication
replace the 70/700 MHz upconverter module A2 (para 5-
of 15 to 35. If the indication is correct, no further testing
is necessary. If the indication is incorrect, proceed to
below and perform the gain adjustments.
step (13) below.
(7) Place the MONITOR switch to the 700
(13) Place and momentarily hold the APC
OUT position. Observe the MONITOR meter for an
switch on the SHF filter/detector module A5 in the test
indication of 5 to 45. If the indication is correct, and tests
position. Observe the monitor meter. If the indication is
b(1) through (13) above have already been completed,
correct, the problem is with the APC circuitry on the A5
no further testing is required.
If the indication is
module. If the indication is incorrect, the problem is the
incorrect, remove and replace the 70/700 MHz
upconverter module A2 (para 5-25b). After replacement,
A5 module; and in either even, remove and replace the
SHF filter/detector module A5.
After replacement,
proceed to paragraph 5-24 below and perform the gain
proceed to paragraph 5-24 below and perform the gain
adjustments.
d. Testing the Frequency Synthesizer Module Al
adjustments.
c. Upconverter with 700 MHz Modem.
(1) Place the MONITOR switch to the IF IN
position.
NOTE
NOTE
The FREQ TUNE must be adjusted to
The APC switch on the SHF
match the frequency dial with the
filter/detector module A5 should be in
FREQ SELECT setting.
the ON position.
5-37
