TM-9-2350-311-10

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; OPERATOR’S MANUAL

NOVEMBER 1994

TM-9-2350-311-10 - Page 353 of 775

TM 9-2350-311-10

2–17 OPERATING AUXILIARY EQUIPMENT —

CONTINUED

2-17.2 Radio and Intercommunication Equipment — Continued

b. Amplifier AM 1780/VRC

1 The amplifier AM-1780/VRC is the master control for the intercommunication system. Nothing works

until both vehicle MASTER switch and amplifier AM-1780/VRC are turned to ON.

Before starting vehicle engine, make certain MAIN PWR switch and amplifier AM-1780/VRC is

set to OFF, Otherwise, engine start could damage amplifier AM-1780/VRC.

2 With vehicle MASTER switch (1) to ON, set MAIN PWR switch (2) to INT ONLY and POWER CKT BRK

switch (3) to ON. POWER lamp (4) should illuminate.

3 Leave INT ACCENT switch (5) at OFF, RADIO TRANS switch (6) at LISTENING SILENCE, and

INSTALLATION SWITCH (7) at INT ONLY.

2-253