Troubleshooting guide

AUDIO INTERNATIONAL, INC. 10/97

Document #540056, Rev. IR, Model No.: PA-7500A

2.3 Cautions & Warnings

2.3.1 All audio connections to the PA-7500A should be shielded and properly

grounded. Perform a pin-to-pin check to confirm that all wires terminate in

their proper location. It is important to do a power and ground check on

the pin connections. Ensure that power and ground are applied only where

required.

2.3.2 DO NOT connect or disconnect the PA-7500A while power is applied.

2.3.3 DO NOT connect or disconnect any speaker when power is applied to the

amplifier.

2.3.4 DO NOT remove any factory-installed screws. Damage to the unit may

result and void any warranties.

2.4 Wiring Requirements

2.4.1 The installing agency must supply and fabricate all external cables. The

length and routing of external cables must be carefully studied and

planned before attempting installation of the equipment. Allow adequate

space for installation of cable and connectors. Avoid sharp bends and

placing cables near aircraft control cables. Maintain a minimum clearance

of three (3) inches from any control cable. If wiring is run parallel to

combustible fluid or oxygen lines, maintain a separation of six (6) inches

between the lines.

2.4.2 All power and ground wires must be 18 AWG minimum. All input and

output lines require twisted, shielded cable with the cable shields

grounded. Power ground wires must be grounded within twelve (12)

inches of the unit. All wires must be in accordance with MIL-W-22759 or

equivalent. Twisted, shielded cable must be in accordance with MIL-W-

27500 or equivalent. Protect power wires with circuit breakers or fuses

located close to the electrical power source bus.

2.4.3 The PA-7500A is designed to interface with other AI equipment via the

RS-485 data bus. This is a bi-directional data bus that allows multiple

units to be connected simultaneously. The lines are daisy-chained

between units with 120-ohm resistors installed at both ends of the wiring

harness. Cable designed specifically for data bus use with 120-ohm

nominal impedance should be utilized. Contact AI for recommended

cables.

2.5 Physical Requirements

2.5.1 Refer to Section 5.1 for unit dimensions.