TM11-5895-846-14
(11) If all of the indications in steps (6) and (7)
(5) If the indication in step (3) above is below
above are correct but the PA MONITOR meter is still
normal, or if the meter is pegged in either direction;
pegged (step 5 above) the problem is in the RF monitor
proceed to step (6) below.
(6)
Place the PA MONITOR switch to the
TEST + 15 V X2 position and observe the MONITOR
(12)
If the fault has not been isolated to
meter for an indication of 15 0.5 Vdc (7.5 0.25).
this point, place the power supply MONITOR switch to
(7)
Place the PA MONITOR switch to the
the positions listed in table 5-8 and check for a correct
TEST 15V X2 position and observe the MONITOR meter
indication on the MONITOR meter. If all indications are
for an indication of 15 0.5 Vdc ( 7.5 0.25).
normal proceed to step (35) below. If indications are not
(8)
f the indication in steps (6) and (7) above
correct, proceed to the step listed in the Step Reference
are correct proceed to step (11) below. If the indications
If Incorrect column in table 5-8.
in steps (6) and (7) above are not correct, place the
(13)
If the 28 V CONT X4, 10 V START
power supply MONITOR switch to the 28 V CONT X4
X2, and 5 V LV CONT X1 indications of step (12) above
position and observe the MONITOR meter for an
were not correct, remove and replace the power supply
indication of 25.5 Vdc (6.4 1).
(9)
f the voltage indication in step (8) above is
(14)
If the 6 V DRIVE X1 indication in step
low (below 21.5 V) the problem is in the power supply
(12) above was not correct, perform steps (15) through
start module A19; remove and replace the module (para
(19) below.
5-20i).
(15) Loosen the eight captive screws on the
(10) f the voltage indication in step (8) above is
front panel of the power supply.
correct, the problem is in the power amplifier RF monitor
(16) Open the power supply drawer.
module A2; remove and replace the module (para 5-
18b).
Table 5-8. Power Amplifier Monitor Meter Indications
Step reference
Position
Indication
if incorrect
280 VDC MAIN X 40
Approximately 240 to 320: (6 to 8) depending
on input voltage and load.
28 V CONT X4
25.5 +4 V (6.4 1)
(13)
10 V START X2
10 2 V (5 i 1)
(13)
5 V LV CONT X1
5.5 1V
(13)
6 V DRIVE X1
6 1.0 V
(14)
6 V FIL X1
6 + 0.3, -0.1 V
(20)
8 V or greater
(21)
BEAM V X1000
7000 100 V (7 0.1)
(29)
8000 V (E) or greater
(21)
COLL MA X100
580 30 MA (5.8 + 0.3)
(35)
BODY MAX5
5 to 30 MA (1 to 6; overload occurs at 45 to
50 MA (9 to 10)
(35)
(17) See figure 5-2. On the pluse synthesizer
indication was 8000 volts or greater, the power supply is
module A4 (A4 LED) observe the fifth and sixth (last)
not being loaded by the klystron. To determine if the
LED indicators, counting from the left.
open circuit is caused by an open klystron filament or an
(18) If either one indicator, or both, is off,
open wire, an ohmmeter continuity check must be
remove and replace the pulse synthesizer module A4
performed; proceed to steps (22) through (28) below.
(22) On the power supply, place the
OPERATESTANDBY switch to the STANDBY position.
(19) If both indicators are on, remove and
(23) Place the START and BLOWER circuit
replace the power supply low voltage module A2 (para 5-
20d).
breakers to the OFF position (the AC POWER indicator
will remain illuminated).
(20) If the 6 V FIL X1 indication in step (12)
(24) Place the MONITOR switch to the BEAM
above was not correct (but not 8 volts or greater) remove
V X1000 position. Observe on the MONITOR meter that
and replace the power supply filament module A14 (para
the beam voltage has decayed to zero volts.
was 8 volts greater refer to step (21) below.
(21) If the 6V FIL x 1 indication in step (12)
above was 8 volts or greater and the BEAM V X1000
5-11
