Replacement of Transmitter Logic Component Assembly A76A5

TM 9-1240-369-34

(12) Insert high voltage cable lead into

(3) Unsolder wires from transmitter logic

flashtube high voltage holder (43). Aline the clearance

component assembly (72) terminals 7, 8, and 10, and tag

hole in the terminal so that it is in line with setscrew (421

for later installation of new transmitter logic component

and tighten setscrew.

assembly.

(13) Install transmitter reflector assembly 1541

(4) Remove potting material from around

and elliptical reflector retainer (53) and secure with screw

connector A76J3 (12), pin A, and unsolder wire from pin

(52).

(14) Install transmitter cover assembly (40) and

(5) Remove two screws (73), two lockwashers

secure with 10 screws (38) and 10 washers (39).

(74), two washers (75) and nut-plate (76) and gently pull

(15) Purge and charge transmitter component

high voltage lead free.

assembly housing in accordance with TM 9-2350230-12.

(6) Remove two screws (77), two washers

Set final pressure to be 3.5 +0.5 psig.

(78), one screw (79), lockwasher (80), washer (81),

(16) Install optical bench assembly as

holddown clamp (82) and remove transmitter logic

instructed in paragraph 3-12 b.

component assembly A76A5 (72).

i. Replacement of Transmitter Logic Circuit Card

(7) Install a new transmitter logic component

Assembly A76A4 (see fig. 3-6).

assembly by performing steps (1) thru (6) in reverse

order.

During installation of new transmitter logic

(1) Remove optical bench assembly as

component assembly A76A5, twist brown lead going to

described in paragraph 3-12 b).

transformer T2 of transmitter logic circuit card assembly

(2) Loosen two captive screws on screw

A76A4 with high voltage lead from A76A5. Install

looking assembly (59) and disconnect connector A4P1

protective sleeving over high voltage lead and tie in place

(60) from harness connector W1J4.

using lacing tape, MIL-T-43435. Install braid (1, table 2-

(3) Remove screw (61), two terminals (62),

10) and insulation sleeving, MIL-I-23053/5, over wire

two washers (63), lockwasher (64), and nut (65) from

from card A76A5, terminal 1, to connector A76J3, pin A,

transformer T2 on transmitter logic circuit card assembly

and pot with sealant, RTV 3145.

(17).

(8) Install optical bench assembly as

(4) Cut strap (66) and remove screw (67) and

instructed in paragraph 3-12 b.

clamp (68).

k. Replacement of PMT chassis Assembly ,A76A6

(5) Remove two screws (69), two washers

(see fig. 3-6).

(70), and transmitter logic circuit card assembly A76A4

(71).

(1) Remove optical bench -assembly as

described in paragraph 3-12 b).

(6) Obtain new clamp (68).

(7) Install new transmitter logic circuit card

(2) Disconnect coaxial lead A7WI (83) from

assembly by performing steps (1) thru (5) in reverse

connector J2.

order.

(3) Loosen two captive screws in screw

(8) Install optical bench assembly as

locking assembly (84) and disconnect connector

instructed in paragraph 3-12 b.

A76W1P1.

j. Replacement of Transmitter Logic Component

(4) Remove two screws (86), two lockwashers

Assembly A76A5 (see fig. 3-6).

(87), two washers (88), and PMT chassis assembly (89)

(5) Install a new PMT chassis assembly by

(1) Remove optical bench assembly as

described in paragraph 3-12 b).

performing steps (1) thru (4) in reverse order. Seal

screws 1841 with sealant, MIL-S-22473.

(6) Reinstall optical bench assembly as

WARNING

instructed in paragraph 3-12 b).

The PFN may retain high voltage

I. Replacement of Video Amplifier A76A7 (see fig.

charges from this 1200 volts

3-6).

developed in the PFN charge power

(1) Remove optical bench assembly as

supply. Before proceeding use a

described in paragraph 3-12 b.

suitable shorting rod with an

(2) Loosen two captive screws on screw

insulated handle to ensure that the

locking assembly (90) and disconnect connector

PFN is fully discharged.

While

A76W1P2 (91).

grounding the shorting rod to the

(3) Disconnect coaxial lead A7W1 (831)from

housing, touch the rod to the high

connector J2 on PMT chassis assembly (89).

voltage terminal at the forward end of

the flashtube.

(2) Remove three screws (76A) from high

voltage terminal cover (76B), remove cover and unsolder

high voltage cable at contact.

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