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JBL SUB125a User Manual

JBL SUB125a
20 pages
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JBL Consumer Products Inc.
250 Crossways Park Drive
Woodbury, N.Y. 11797
1-800-336-4JBL in the USA
A Harman International Company
Rev A 11/99
SUB125/125a
Amplifier/Subwoofer
SERVICE MANUAL
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JBL SUB125a Specifications

General IconGeneral
Frequency Response35Hz – 120Hz
Amplifier Power125W
TypeActive Subwoofer
Power Output125W
Driver Size12-inch
Input ConnectionsRCA, Speaker Level
Enclosure TypeBass Reflex
InputsLine-level, Speaker-level

Summary

GENERAL SPECIFICATIONS

CONTROLS AND THEIR FUNCTION

Speaker Level Outputs

Connect Left, Center, and Right speakers to these terminals.

Speaker Level Inputs

High-level inputs for receivers without 'pre-amp out' or 'subwoofer out'.

Line Level Inputs

Left and right inputs for receivers with line-level 'pre-amp out'.

Auto/On Switch Operation

Sets amplifier mode for auto turn-on/off.

Subwoofer Level Control

Knob that controls the subwoofer's volume level.

Status LED Indicators

Red and Green LEDs indicate subwoofer status.

Power Switch

Master power switch to disconnect the amplifier.

Fuse and AC Cord

Details on fuse type and AC power cord connection.

SPEAKER LEVEL CONNECTIONS

LINE LEVEL CONNECTIONS

TEST SET UP AND PROCEDURE

General Function Test

Basic operational tests for line and speaker level inputs.

Sweep Function Test

Testing with a sweep generator for cabinet noises.

Driver Function Test

Testing driver DC resistance and noise.

SIMPLE TROUBLESHOOTING

No Sound Issues

Troubleshooting steps for no sound from speakers.

Low Volume Performance

Troubleshooting system shutoff at increased volumes.

Low Bass Output

Troubleshooting steps for low bass output.

Surround Sound Issues

Troubleshooting no sound from surround speakers.

Service Bulletin JBL9901

PACKING CONTENTS

EXPLODED VIEW (Part 1)

EXPLODED VIEW (Part 2) and Parts List

PCB COMPONENT SIDE DIAGRAM

PCB SOLDER SIDE DIAGRAM

ELECTRICAL PARTS LIST

ELECTRICAL PARTS LIST (Continued)

INTEGRATED CIRCUIT DIAGRAMS

POWER AMP SCHEMATIC DIAGRAM

PRE-AMP SCHEMATIC DIAGRAM

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