TM11-5895-846-14
(25) On the front panel of the PA, loosen the
(3) If the blower is not operating, check the
thirteen quarter-turn fasteners on the access cover and
power supply BLOWER circuit breaker. If the circuit
remove the cover.
breaker is tripped (in the OFF position) reset it.
(26) Using a multimeter set to the X1 OHM
(4) If step (3) above does not correct the fault,
scale, measure the resistance between the klystron
the problem is in the PA klystron blower B1; remove and
replace the blower (para 5-18c and d).
heater and cathode terminals.
c.
INTERLOCKS Faults and HV INHIBIT Status
(27) If the resistance measured in step (26)
above was greater than 3 ohms, remove and replace the
Indicators.
klystron (para 5-18a and f).
(1) Place
the
power
supply
(28) If the resistance measured in step (26)
OPERATESTANDBY switch to the STANDBY position.
above was less than 3 ohms, an open circuit exists in the
(2) On the power amplifier (PA) disconnect
klystron filament wiring between the PA heater/cathode
the clamp securing the SHF output waveguide flange to
terminals and the power supply drawer or the power
the shelter waveguide flange and free the mated flanges.
supply filament module A14. Refer the problem to the
(3) Remove the cables from the SHF IN and
next higher level of maintenance.
SHF TEST OUT connectors.
(29) If all the indications in step (12) above
(4) Loosen the eight captive screws on the
were correct except the BEAM V X1000 indication was
PA front panel.
below normal value, perform steps (30) through (34)
(5) Pull on the two handles to extend the PA
below.
to its open position.
(30) Repeat steps (15) and (16) above.
(6) Tighten all of the -turn fasteners which
(31) See figure 5-2. On the pulse synthesizer
secure the top cover, bottom cover, right side access
module A4 (A4 LEDs) observe the LED indicators.
cover, and front access cover to ensure that the interlock
(32) If any one or more of the indicators in step
switches are in their closed positions.
(31) above is off, remove and replace the pulse
(7) If the INTERLOCKS lamp is still
synthesizer module A4 (para 5-20d).
illuminated, close the PA drawer, secure the captive
(33) Observe the LED indicators on the high
screws and proceed to step (8) below.
voltage switching module A5 through A12 (A5 LED
(8) Loosen the eight captive screws on the
through A12 LED, fig. 5-2).
power supply front panel.
(34) If any one or both of the indicators in step
(9) Open the power supply drawer.
(33) above is off on a module, remove and replace that
(10) Tighten all the -turn fasteners which
module (para 5-20e).
secure the top cover on the power supply to ensure that
(35) If all the indications in step (12) above
the interlock switch is closed.
were correct, place the PA MONITOR switch to the
(11) If the INTERLOCKS lamp is still
upper scale X15 WATTS position (black stencil).
illuminated, remove the top cover and check the
(36) On the PA, unlock and then adjust the
operation of the interlock switch.
OUTPUT LEVEL control for an approximate midscale, or
(12) If the operation of the interlock switch is
lower, indication on the MONITOR meter.
satisfactory, the problem is in the power supply control
(37) Place the power supply MONITOR switch
and overload module Al; remove and replace the module
to the BODY MA X5 position. Observe the MONITOR
meter for an indication of 6 (30 ma) or lower.
(13) After correction of the fault, close the
(38) On the PA, adjust the OUTPUT LEVEL
power supply drawer and tighten the eight captive screws
control to slowly increase the output level while observing
on the front panel. Replace the cables and waveguide
both MONITOR meters.
on the front panel of the PA.
d. TEMP LOAD Fault and HV INHIBIT Status
(39) If the power supply MONITOR meter
indication BODY MA increases above normal and the PA
Indicators. This fault is an indication of reflected power
MONITOR meter output level does not increase or
on the output waveguide system involving the power
increases only slightly, remove and replace the klystron
amplifier (PA), the flexible waveguide to the patch panel,
the antenna waveguide and the feed horn. The fault will
b.
TEMP-KLYSTRON Fault and HV INHIBIT
occur when the internal load has an excessive
Status Indicators.
temperature condition and the thermal switch has
opened. Before this procedure can be accomplished it
(1) Check (by listening) that the PA klystron
will be necessary to wait until the load has cooled, the
blower is operating.
thermal switch has reset itself and output power is
(2) If the blower is operating, check the inlet
restored.
and exhaust louvers for obstructions or dirty filters;
remove obstructions or clean filters as necessary.
5-12
