Initial Conditions and Checks

TM 11-5895-1123-34

calibration to determine if the meter is faulty, proceed as

(20) Return the lower and upper voltage limit cursors

follows.

to 110 and 120 volt settings, respectively.

(4) By use of the two adjustment screws at the

d. Replacement of Meter-Relay, M1.

meter window, swing the red limit cursors away from the

(1) Remove the VR monitor panel from its rack as

115 volt position so that the lower limit cursor lies at 90

outlined in paragraph 328 above.

volts and the upper at 140 volts. These wide settings are

(2) Tag the leads according to their destinations at

to prevent unwanted fault latchups when the calibration

the rear of the meterrelay unit.

screw is adjusted later on.

(3) Slide the protective sleeves back along the leads

(5) Turn off the power to racks 4, 5, and 6 at the

to expose the solder joints and unsolder the leads from

power distribution panel.

the meter pins.

(6) Loosen the four captive screws retaining the

(4) Remove the three mounting screws and

panel to the rack and carefully pull the panel away from

dismount the meter and the zero adjust protective cover

the rack.

from the panel.

(7) Remove the four screws retaining the plastic

(5) Secure the replacement meterrelay unit to the

protective cover to the support posts at the rear of the

front panel with a screw, lockwasher and nut at the

panel and remove the protective cover.

topmost of the three mounting holes.

(8) Slightly loosen the two lower mounting screws

CAUTION

for the monitor meter and swing the calibration screw

Do not alter the setting of the meter zeroadjust screw.

cover away to permit access to the screw.

This screw is the lower one of the three adjustment

screws passing through the meter window, and can be

NOTE

properly set only by using a highly accurate voltage

The adjustment cover is slotted on one

standard as described in paragraph 329c below.

side so that it may be pivoted about the

(6)

Place the zeroadjust protective cover over the

other mounting screw, thus making it

lower part of the meter face and align the mounting

unnecessary to entirely remove the

holes. Install the remaining two mounting screws.

mounting screws.

(7) Set the lower and upper voltage limit cursors to

(9) Temporarily remount the VR monitor panel to the

110 and 120 volts, respectively, using the two exposed

rack and tighten the four captive mounting screws

adjustment screws at the meter face.

sufficiently to hold the panel in place.

(8) Solder the leads to the five pins at the rear of the

(10) Reapply power to racks 4, 5, and 6.

replacement meter.

(11) Actuate the fault reset switch.

(9) Remove the lead tags and slip sleeving back

(12) Insert the Fluke 8000A Digital Multimeter test

over the soldered pin connections.

probes into the regulated 115 vac receptacle and

(10) Mount the VR monitor panel on the rack as

observe the reading.

outlined in paragraph 330 below.

(13) Adjust the monitor meter calibration screw so

e. Replacement of Switch S1.

that the indicated voltage is the same as that of the

(1) Remove the VR monitor panel from the rack as

8000A multimeter.

outlined in paragraph 328 above.

(14) If the monitor meter reading cannot be set to

(2) Remove the two leads one at a time from the

duplicate the multimeter indication, the monitor meter or

screw terminals at the rear of the switch and connect to

its wiring is defective. See the monitor meterrelay

new switch.

replacement procedure in paragraph 329e below.

(3) Remove the switch retaining nut at the front of

(15) If the meter calibration of step 13 was

the panel taking care not to mar the panel finish.

successful, turn off the power to racks 4, 5, and 6 and

(4) Remove switch.

remove the panel from the rack.

(5) Insert replacement switch in panel hole taking

(16) Return the monitor meter calibration screw cover

care that the tab on the antirotation washer is seated in

to its normal position and tighten the meter mounting

the small recess hole at the rear of the panel.

screws.

(6) Install switch retaining nut and tighten.

(17) Reinstall the protective plastic cover and secure

(7) Mount the VR monitor panel on its rack as

it to the mounting posts with the four screws.

outlined in paragraph 330 below.

(18) Position the panel on the front of the rack and

f. Replacement of Indicator Lamp DS1.

tighten the four captive screws to secure it to the rack.

(1) Remove lens assembly from lamp socket by

(19) After power has been reapplied to racks 4, 5,

and 6, actuate the fault reset switch.

3-51