JBL A6000GTi User manual

A6000GTi
Car Audio
Power Amplifier
Service Manual
2003 by Crown Audio, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000
U.S.A. Telephone: [phone]. Trademark Notice: Crownis a
registered trademark of Crown International, Inc; JBLis a registered
trademark of JBL. Other trademarks are the property of their respective
owners. 137159-1
11/03
Rev. 1

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. II
The information furnished in this manual does not include all of the details of
design, production, or variations of the equipment. Nor does it cover every
possible situation, which may arise during installation, operation or
maintenance. If you need special assistance beyond the scope of this
manual, please contact the JBL Technical Support Group.
This document contains data proprietary to Crown Audio, which was
developed at private expense. Crown Audio reserves all rights in
connection with this document and in the subject matter presented therein.
The recipient hereby acknowledges these rights and shall not, without
Crown Audio’s prior written permission, copy, disclose or divulge this
document in whole or in part to third parties or use it for any purpose other
than that for which it was delivered to the recipient.
TO PREVENT ELECTRIC
SHOCK DO NOT REMOVE TOP
OR BOTTOM COVERS. REFER
SERVICING TO QUALIFIED
SERVICE PERSONNEL.
TO REDUCE THE RISK OF ELECTRIC
SHOCK, DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE!
The exclamation point
triangle is used to alert
the user to important
operating or maintenance
instructions.

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. III
Revision History
Revision Number Date Comments
Rev. 1 11-2003 Initial Draft

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. IV
This page intentionally left blank

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. V
Table of Contents
1. INTRODUCTION ..................................................................................................... 1-1
1.1. THE A6000GTI CAR AMPLIFIER ........................................................................... 1-1
1.2. SCOPE............................................................................................................... 1-1
1.3. WARRANTY......................................................................................................... 1-1
2. SPECIFICATIONS................................................................................................... 2-1
2.1. OUTPUT POWER ................................................................................................. 2-1
2.2. PERFORMANCE................................................................................................... 2-1
2.3. CONTROLS &CONNECTORS................................................................................. 2-2
2.4. INDICATORS........................................................................................................ 2-2
2.5. INPUT/OUTPUT.................................................................................................... 2-2
2.6. PROTECTION ...................................................................................................... 2-3
3. THEORY OF OPERATIONS ................................................................................... 3-1
3.1. AUDIO SIGNAL PATH............................................................................................ 3-1
3.1.1. Input Stage................................................................................................ 3-1
3.1.2. Error Amplifier............................................................................................ 3-2
3.1.3. Modulator .................................................................................................. 3-2
3.1.4. Triangle Generator..................................................................................... 3-2
3.1.5. Output........................................................................................................ 3-3
3.1.6. Output Filter............................................................................................... 3-4
3.2. PROTECTION AND CONTROL CIRCUITRY ................................................................ 3-5
3.2.1. Current Monitor.......................................................................................... 3-5
3.2.2. Current Limiter........................................................................................... 3-5
3.2.3. Display Circuitry......................................................................................... 3-5
3.2.4. Thermal Limit Control (TLC) ...................................................................... 3-6
3.3. POWER SUPPLY.................................................................................................. 3-7
3.3.1. Switching Power Supply Operation............................................................ 3-7
3.3.2. Switching Power Supply Protection Circuit ................................................ 3-7
3.3.3. (LVPS) Low Voltage Power Supply Operation ........................................... 3-7
4. MAINTENANCE ...................................................................................................... 4-1
4.1. WHERE TO BEGIN................................................................................................ 4-1
4.2. SURFACE MOUNT TECHNOLOGY........................................................................... 4-1
4.3. DISASSEMBLY FOR INSPECTION &SERVICE............................................................ 4-2
4.3.1. Top Cover Removal................................................................................... 4-2
4.3.2. Power Supply Discharge............................................................................ 4-4
4.3.3. Power Connection Housing Removal ........................................................ 4-5
4.3.4. Pip Assembly Removal.............................................................................. 4-6
4.3.5. Power Supply Assembly Removal............................................................. 4-7
4.3.6. BCA Assembly Removal............................................................................ 4-7
4.3.7 BCA Disassembly...................................................................................... 4-8
4.4. TROUBLESHOOTING............................................................................................. 4-9
4.4.1. Power Supply ............................................................................................ 4-9
4.4.2. Audio Section Trouble Shooting............................................................... 4-10

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. VI
4.4.3. Fault Modes............................................................................................. 4-10
4.5. REQUIRED TEST EQUIPMENT.............................................................................. 4-12
4.6. ELECTRICAL CHECKOUT PROCEDURE ................................................................. 4-12
4.6.1. Quiescent Current Draw .......................................................................... 4-13
4.6.2. Sensitivity ................................................................................................ 4-13
4.6.3. Bridge Mono Operation............................................................................ 4-13
4.6.4. Frequency Response............................................................................... 4-13
4.6.5. Short Circuit Test..................................................................................... 4-13
4.6.6. Output Power........................................................................................... 4-13
4.7. CALIBRATIONS .................................................................................................. 4-14
4.7.1. Amplifier Power up:.................................................................................. 4-14
4.7.2. DC offset adjustment: .............................................................................. 4-14
4.7.3. Overlap correction: .................................................................................. 4-14
4.7.4. Current Monitor adjustment: .................................................................... 4-14
5. PARTS .................................................................................................................... 5-1
5.1. GENERAL INFORMATION....................................................................................... 5-1
5.2. ORDERING AND RECEIVING PARTS........................................................................ 5-1
5.2.1. Terms........................................................................................................ 5-1
5.2.2. Shipment ................................................................................................... 5-1
5.3. MECHANICAL PARTS............................................................................................ 5-1
5.4. CIRCUIT BOARD PARTS........................................................................................ 5-2
5.4.1. Circuit Board and Schematic Part Numbers............................................... 5-2
6. SCHEMATICS......................................................................................................... 6-1

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. Introduction
1-1
1. Introduction
This manual contains complete service information on the JBL A6000GTi power amplifier.
It is designed to be used in conjunction with the A6000GTi Owner’s Manual; however,
some important information is duplicated in the Service Manual.
NOTE: THE INFORMATION IN THIS MANUAL IS INTENDED FOR USE
BY AN EXPERIENCED TECHNICIAN ONLY!
1.1. The A6000GTi Car Amplifier
The A6000GTi is an extremely high output audio amplifier designed for automotive use,
providing high power amplification from 20Hz –400Hz with minimum distortion. The
A6000GTi features Crown’s patented, awarded-winning BCA(Balanced Current
Amplifier) engineering, for superior power output, increased efficiency, legendary Crown
sound and extraordinary reliability. Other features include parallel mode operation for
driving loads below 2 Ohms, selectable 12/24 dB/octave crossover slope, phase
adjustment and DBO (Dynamic Bass Optimization).
1.2. Scope
This Service Manual is intended to apply to all versions of the A6000GTi amplifier. The
Parts Listings include parts specific for all versions. Parts are available from the Crown
Parts Department.
1.3. Warranty
Each Reference Manual contains basic policies as related to the customer. In addition, it
should be stated that this service documentation is meant to be used only by properly
trained personnel. All warranty service should be referred to the Crown Factory or JBL
Authorized Warranty Service Center. See Figure 1.1 for a copy of the Warranty. To find
the location of the nearest Authorized Warranty Service Center or to obtain instructions for
receiving Factory Service, please contact the JBL Technical Support Group. If you are an
Authorized Warranty Service Center and have questions regarding the warranty of a
product, please contact the JBL Technical Support Group.
JBL Technical Support
Phone: [phone]JBL
Phone: [phone]
Web Page: http://www.jbl.com
Customer Support
Factory Service
Parts Department
Mailing Address: P.O. Box 1000, Elkhart, IN 46517
Shipping Address: Plant 2 S. W.
1718 W. Mishawaka Rd., Elkhart IN 46517
Phone: [phone]
Fax: [phone]
http://www.crownaudio.com

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. Introduction
1-2
Figure1.1 JBL Warranty

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. Specification 2-1
2. Specifications
2.1. Output Power
A6000GTi Power Chart
Maximum power @ 100Hz With 0.1% THD
2 ohm Dual 3000W
4 ohm Bridged 6000W
1 ohm Parallel 6000W
Load Impedance: Safe with all types of loads. Rated for 2 ohms in dual mode, 4 ohms in
Bridged and 1 ohm in Parallel.
Required Battery Voltage: 10.0-16.0 VDC
DC Line Current:
For 6000W: 700A;
At idle: Amp draws 12.0A and no more than 200 watts.
2.2. Performance
Frequency Response: ±3dB from 10Hz to 200Hz at 1 watt.
Phase Response: 0 to 180 degrees deviation from 20Hz to 320Hz.
Signal to Noise Ratio, A-Weighted, 20Hz to 320Hz: Better than 100dB below rated
100Hz power.
Total Harmonic Distortion (THD): 100Hz rated power 0.1% or less THD
Damping Factor: Greater than 1000 from 10Hz to 400Hz
Common Mode Rejection (CMR): Better than 70dB from 20Hz to 100Hz.

137159-1 Rev. 1 A6000GTi Service Manual
2003 Crown Audio, Inc. Specification 2-2
2.3. Controls & Connectors
Power: REM voltage of 5.0VDC will power up the amplifier. REM voltage of less than
3.0VDC will power down the amplifier.
Mode: Turn power off before switching. A two-position switch located in the middle of the
input panel, when switched to 2CH/BR operates the amplifier either in two “mono”
channels or one bridge channel. When switched to PARALLEL, the amplifier joins the two
output channels to deliver twice the output current.
Sensitivity: A continuously variable rotary level control that when turned to the maximum
setting with an input of .250mV RMS the amplifier will deliver maximum output power.
When turned to the minimum setting with an input of 8.0Vrms the amplifier will deliver
maximum output power.
Slope: Two-position switch used to control filter rolloff. Switch in 12 pos yields 12dB per
octave rate of rolloff. Switch in 24 pos yields 24dB per octave rate of rolloff.
LP Freq: Crossover frequency adjustment from 32Hz to 320Hz.
DBO: Dynamic Bass Optimization. Two-position switch turns DBO on and off.
Continuous rotary adjustment to increase/decrease bass level. Another adjustment for HP
rolloff.
2.4. Indicators
Signal: A blue LED, which flashes when a very low-level signal is present at input.
Clip: A red LED, which turns on when distortion becomes audible in the amplifier output.
Fault: Normally off, this red indicator will light if amplifier output stage becomes non-
operational.
Power: A blue LED that turns on when the amplifier has been turned on and has power.
2.5. Input/Output
Input Connector: One RCA connector for each channel.
Input Impedance: 25k ohms
Output Connectors: Custom gold plated terminals with set screws.
Power Connectors: Custom gold plated terminals with set screws accepting 0 gauge
hookup wire.
Wiring Diagram: See A6000GTi Owner’s Manual