Sigtronics SAS-640 User Manual

Page 2

CHASSIS INSTALLATION

To upgrade an existing SPA-400 installation to a SAS-440

or a SPA-600 to SAS-640 skip to the “UPGRADING A

SPA INSTALLATION TO A SAS” section on page 3. For a

completely new intercom installation continue below.
Hardware Supplied
Besides the intercom unit and these instructions, each SAS

system comes with the following hardware:

SAS-440 SAS-640

Headphone Output Jacks - Accept standard

0.250” aircraft headphone plugs.

Microphone Input Jacks - Accept standard

0.206” aircraft microphone plugs. (U93 plug

compatible jacks can be used in place of the

jacks provided).

Mic Jack Insulating Washers, Flat

Mic Jack Insulating Washers, Shoulder

Intercom Panel - lettered on both sides.

Intercom Control Knobs

Mounting Screws 4-40 x 1/2

Drill Template - Adhesive backed hole size

pattern for drilling aircraft panel.

Aircraft / Intercom Interface Cable (4 feet long) 1

Single White / Green Wire with pin (4 feet long) 1

UNIT PLACEMENT
The SAS unit has been designed to mount either horizontally

or vertically in your aircraft panel.
The location selected for the SAS unit requires a minimum

front panel area of 2 1/2” by 1”. Depth required behind panel

is 6” plus cable access.
CAUTION: Move the aircraft flight controls through the limits

of travel while observing the selected area and making sure

that the rear of the intercom and cable will not interfere with

any aircraft control components.

PANEL PREPARATION:
1. Position the adhesive drill template on the aircraft panel

in the selected area.

2. Center punch each hole at the cross lines. (The five holes

are in a straight line and equally spaced 0.4” apart).

3. Drill 1/8” pilot holes in all five places.
4. Enlarge two holes to 3/8” and one hole to 1/2” per the

template.

MOUNTING CHASSIS: See Figure 2
1. Remove the knobs from the Volume and OFF/ALL/ISO

controls using a 0.050” Allen wrench. NOTE: DO NOT

REMOVE the nuts from the Volume, Squelch, or OFF/

ALL/ISO controls.

2. Insert the SAS unit from the rear of the aircraft panel

with the appropriate arrow on the unit chassis pointing

upwards.

3. Install the printed SAS panel and lightly thread the two

4-40 screws through the holes in intercom panel. The

nuts on the Volume and OFF/ALL/ISO controls should fit

inside the 3/8” diameter holes.

4. Tighten the two screws.
5. Put the knobs on the Volume (VOL) and OFF/ALL/ISO

control shafts and tighten the Allen screws.

MOUNTING HEADPHONE AND MICROPHONE JACKS

(See Figure 3)
1. Locate the mounting areas. (One mic and one headphone

jack required for each headset). Again, make sure that

the jacks will not interfere with any aircraft control

components.

2. Drill 3/8” diameter holes for headphone jacks and

install.

3. Drill 1/2” diameter holes for the mic jacks and install with

the insulating washers supplied. (See Figure 3).

Note: If the aircraft already has pilot headset jacks, they

can be used for intercom, however, the mic jack must be

re-wired as follows:
1. Remove any existing wires from the tip, ring, and barrel

connections.

2. Connect the intercom White / Black wire to the ring

terminal.

3. Connect one end of a ground wire to the barrel terminal

of the mic jack and connect the other end to Point “A”.

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FIGURE 2

FIGURE 3

MICROPHONE JACK

This manual is related to the following products:

SAS-440