Figure 4-4. Disassembly of valve subassembly.

TM 9-6685-202-14

NOTE

(1) Remove evacuation manifold (1) and

Older barometers already in service

glass trap (47) by removing screw (2), clamps (3), and

nut on union (4).

use the thermometer rod as one

current path to the light bracket, and

(2) Remove top cap sleeve (5) by removing

the other members of the barometer

three socket head cap screws (6).

serve as a ground return. Therefore,

NOTE

in disassembling such models,

Do not remove top cap assembly

carefully preserve the three insulator

unless it is to be replaced.

washers

that

insulate

the

(3) Disconnect plastic tubing (7) from glass

thermometer rod from the top

stem on side of barometer tube.

mounting disc and the cistern base

(4) Unscrew tube evacuating nipple (8) from

which are in contact with the

top mounting disc (9).

grounded items. The light source tip

(5) Unlock barometer tube (10) by loosening

jack electrical lead on older models

gland nut on cistern base.

is attached by means of a terminal

(6) Lift barometer tube out of gland nut, slide

lug and screw to the bottom of the

tube through slot cut in top mounting disc (9), and

thermometer rod. In requisitioning a

remove from barometer.

replacement "light source tip jack"

(7) Remove top mounting disc (9) by

indicate the model of barometer

removing two socket head cap screws (11).

under repair.

(8) Free block (12) by removing setscrew

(21) Remove the thermometer rod (43) and

(13), socket head cap screw (14), and fat washer (15).

the scale rod (44) by removing the socket head cap

(9) Slide block off the scale rod.

screws (45) and (46) attaching the rods from the

(10) Remove cable clamp(16) by removing

underside of the cistern and base assembly.

socket head cap screw (17).

(22) The barometer is now disassembled into

(11) Unplug light source tip jack (18) from

its subassemblies which can in turn be further

receptacle on platform.

disassembled for utilization of authorized repair parts

(12) Carefully slip vernier slide assembly (19)

according to instructions in the following subparagraphs.

off the scale rod.

(13) Do not remove thermometer (22) or its

holder unless it is defective. If it is necessary to replace

the thermometer, remove thermometer holder (20) by

removing two socket head cap screws (21) and remove

thermometer from clay block inserts (23) in which it is

imbedded.

(14) On the type A-1, remove cam bar (24) by

removing cam bar stud (25) secured by socket head cap

screw (26) and flat washers (27) and (28).

(15) Remove scale (29) secured to scale rod

by two socket head cap screws (30) and flat washers

(31).

(16) Unscrew adjusting rod (32) from adjusting

bracket (33) and recover adjusting nut (34) and spring

washer (35).

(17) Remove adjusting bracket (33) by

removing socket head cap screw (36).

(18) Remove micrometer (37) from cistern lid.

(19) Remove gage block mount (38) by

removing two socket head cap screws (39).

(20) Separate cistern base assembly (40) from

platform assembly (41) by removing two socket head

cap screws (42) set in the top of the cistern base

assembly.

MI (C) 6685-202-14-4-4

Figure 4-4. Disassembly of valve subassembly.

4-12