JBL A6000GTi Service Manual
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JBL A6000GTi Service Manual

JBL A6000GTi Service Manual

Car audio power amplifier
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A6000GTi
Car Audio
Power Amplifier
Service Manual
2003 by Crown Audio, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000
U.S.A. Telephone: 574-294-8000. 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

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Summary of Contents for JBL A6000GTi

  • Page 1 2003 by Crown Audio, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone: 574-294-8000. 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.
  • Page 2 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.
  • Page 3 137159-1 Rev. 1 A6000GTi Service Manual Revision History Revision Number Date Comments Rev. 1 11-2003 Initial Draft 2003 Crown Audio, Inc.
  • Page 4 137159-1 Rev. 1 A6000GTi Service Manual This page intentionally left blank 2003 Crown Audio, Inc.

  • Page 5: Table Of Contents

    137159-1 Rev. 1 A6000GTi Service Manual Table of Contents INTRODUCTION ..................... 1-1 1.1. A6000GT ................1-1 MPLIFIER 1.2........................ 1-1 COPE 1.3......................1-1 ARRANTY SPECIFICATIONS ....................2-1 2.1....................2-1 UTPUT OWER 2.2....................2-1 ERFORMANCE 2.3. & C .................
  • Page 6 137159-1 Rev. 1 A6000GTi Service Manual 4.4.3. Fault Modes ..................... 4-10 4.5................4-12 EQUIRED QUIPMENT 4.6..............4-12 LECTRICAL HECKOUT ROCEDURE 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.

  • Page 7: Introduction

    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.
  • Page 8 137159-1 Rev. 1 A6000GTi Service Manual Figure1.1 JBL Warranty 2003 Crown Audio, Inc. Introduction 1-2...

  • Page 9: Specifications

    137159-1 Rev. 1 A6000GTi Service Manual 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.

  • Page 10: Controls & Connectors

    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 2003 Crown Audio, Inc. Specification 2-2...

  • Page 11: Protection

    137159-1 Rev. 1 A6000GTi Service Manual 2.6. Protection A6000GTi amplifiers are protected against shorted, open or mismatched loads, overloaded power supplies, excessive temperature, input overload damage and high frequency blowups. They also protect loudspeakers from input/output DC, large or dangerous DC offsets and turn-on/turn-off transients.

  • Page 12: Theory Of Operations

    Gaussian low pass filter has been included in the input stage of the A6000GTi (on the input PWA). The Gaussian filter-type is unique in that it has minimal ringing and excellent phase response so even a high-order filter such as this one does not adversely affect the sonic excellence of the product.

  • Page 13: Error Amplifier

    137159-1 Rev. 1 A6000GTi Service Manual 3.1.2. Error Amplifier The signal next enters the main amplifier error amp (U500-D) where it is mixed with a small portion of the output voltage and current in such a way as to control the amplifier’s overall output performance.

  • Page 14: Output

    137159-1 Rev. 1 A6000GTi Service Manual 3.1.5. Output The PWM modulated 125kHz signals exit the modulators and enters a voltage translator formed by Q301 – Q310. This string translates the balanced PWM signals into a single ended waveform with increased amplitude for the FET driver (U301 and U302). The FET driver’s output is increased by a two transistor discrete amplifier stage for improved fan out...

  • Page 15: Output Filter

    137159-1 Rev. 1 A6000GTi Service Manual Now, back to the description of output circuit flow: after the FETs, the signal is then routed to the BCA filter inductors (Lp and Ln). The combining point (B1) is then sent to the Output Filter.

  • Page 16: Protection And Control Circuitry

    3.2.2. Current Limiter To prevent excessive output current, the A6000GTi incorporates an active current limit circuit for each channel. Resistors (R809-R811, R812-R814) in series with the Lp and Ln output coils are used to sense the output current. The voltage created by the output current thru the resistors is compared to a reference voltage set by R801 &...

  • Page 17: Thermal Limit Control (Tlc)

    137159-1 Rev. 1 A6000GTi Service Manual disabled, and a crowbar circuit is employed to drain the rail voltage to prevent any further damage. 3.2.4. Thermal Limit Control (TLC) The TLC circuit is used to control the output of the amplifier while monitoring the temperature of the amplifier output devices and of the power supply switching devices.

  • Page 18: Power Supply

    137159-1 Rev. 1 A6000GTi Service Manual 3.3. Power Supply 3.3.1. Switching Power Supply Operation The switching power supply is designed to take 12-volts in and convert it to +/- 150-volts out using a full bridge topology. The ring of mosfets around the transformer in the middle of the supply can be divided into 6 parallel H bridges, with each bridge having 2 mosfets per leg (for a total of 48 mosfets).
  • Page 19 137159-1 Rev. 1 A6000GTi Service Manual transformer, then rectified by the diodes on the secondary (D8, D9, D11, D12), and filtered by L7 with C43 and by L8 with C49 to give the +/-24 volt outputs. The +24 volt is monitored by the PWM thru the resistor divider formed by R60 and R59.

  • Page 20: Maintenance

    4.2. Surface Mount Technology The A6000GTi amplifier uses surface mount technology in its design. There are several advantages to using surface mount technology (SMT), including; (1) surface mount devices (SMDs) are much smaller, and are mounted to the surface of the board, so more components can be placed on the board.

  • Page 21: Disassembly For Inspection & Service

    137159-1 Rev. 1 A6000GTi Service Manual 4.3. Disassembly for Inspection & Service The extent of disassembly required will depend upon the extent of inspection and service required. Note: To avoid the risk of electric shock, turn off and unplug the amplifier from the +12V power source before disassembly or reassembly is attempted.
  • Page 22 137159-1 Rev. 1 A6000GTi Service Manual 8. Using a T-15 screwdriver, remove the two Torx-head screws on the display board. Disconnect the ribbon cable from the back of the display board. 9. Using a T-15 screwdriver, remove the 23 Torx-head screws on the perforated shield.

  • Page 23: Power Supply Discharge

    137159-1 Rev. 1 A6000GTi Service Manual 4.3.2. Power Supply Discharge Before any connectors and PWAs (Printed Wire Assemblies, or circuit boards) are removed, the Power Supplies need to be discharged. Follow these simple steps. 1. Make sure the amplifier is disconnected from the +12Volt Power Source.

  • Page 24: Power Connection Housing Removal

    137159-1 Rev. 1 A6000GTi Service Manual 4.3.3. Power Connection Housing Removal 1. Peel the rubber pad off bottom of the amp. 2. Using a T-15 screwdriver, remove the four Torx-head screws from the bottom of the amplifier holding the plastic power housing to the chassis.

  • Page 25: Pip Assembly Removal

    137159-1 Rev. 1 A6000GTi Service Manual 4.3.4. Pip Assembly Removal 1. Using a T-15 screwdriver, remove the five Torx-head screws from the bottom of the amplifier holding the plastic pip holder to the chassis. 2. Disconnect the two ribbon cables from the pip board. Both of these cable connectors have latches.

  • Page 26: Power Supply Assembly Removal

    137159-1 Rev. 1 A6000GTi Service Manual 4.3.5. Power Supply Assembly Removal 1. Remove power Connection (see Section 4.3.2 for Power Supply Discharge). 2. Using a T-20 screwdriver, remove the four large Torx-head screws from the bottom of the amplifier. 3. Remove one round standoff (used for the display board) using pliers.

  • Page 27: Bca Disassembly

    137159-1 Rev. 1 A6000GTi Service Manual 4.3.7 BCA Disassembly 1. Remove BCA assembly from amplifier (see Section 4.3.6). 2. Using a Philips screwdriver, remove four screws holding coils down. 3. Under the four screws just removed there is a plastic cap (large washer). Remove all four caps.

  • Page 28: Troubleshooting

    137159-1 Rev. 1 A6000GTi Service Manual 4.4. Troubleshooting As mentioned earlier, the three steps to effective repair are: Determine the symptoms; identify the cause of the symptoms; repair the unit to eliminate the cause. Please troubleshoot based on the order listed below.

  • Page 29: Audio Section Trouble Shooting

    137159-1 Rev. 1 A6000GTi Service Manual If the voltage is still low, the problem is in the LVPS. Check the gate drive signals into the mosfets Q50 & Q54 (on Power Supply PWA). Verify that the two mosfets are switching. If there is a gate drive signal, but no switching, verify that the two drains are connected to ground thru a 0.04-ohm resistor (R58).
  • Page 30 137159-1 Rev. 1 A6000GTi Service Manual HF: The amplifier senses high frequency oscillations with frequencies outside of the audio bandwidth. The most likely cause for this fault is that the diodes D801 & D901 on the output filter board are bad. If this does not correct the problem, replace the front-end boards.

  • Page 31: Required Test Equipment

    137159-1 Rev. 1 A6000GTi Service Manual 4.5. Required Test Equipment Due to the complex circuitry utilized in the A6000GTi amplifier, special calibration procedures and the correct test equipment are necessary to insure original factory specifications are achieved. Below, in Figure 4.9, is a list of test equipment needed to successfully service the amplifier.

  • Page 32: Quiescent Current Draw

    137159-1 Rev. 1 A6000GTi Service Manual 4.6.1. Quiescent Current Draw Spec: 12 amps Procedure: with no load connected, turn amplifier on. Measure the DC current draw of amplifier. It should be approximately 12 amps. 4.6.2. Sensitivity Spec: 0.25mV to 8V Procedure: No load.

  • Page 33: Calibrations

    137159-1 Rev. 1 A6000GTi Service Manual Procedure Parallel Mode: Load the amplifier with 1 ohm from Ch1+ to Ch1-. Place a jumper from Ch1+ to Ch2-. Inject a 100 Hz signal. Increase the input until the output reaches 77.5 volts. THD should be less then 0.1%.

  • Page 34: Terms

    137159-1 Rev. 1 A6000GTi Service Manual 5. Parts 5.1. General Information Replacement parts for this amplifier can be ordered from the Crown Parts Department. PART PRICES AND AVAILABILITY ARE SUBJECT TO CHANGE WITHOUT NOTICE. 5.2. Ordering and Receiving Parts When ordering parts, be sure to give the product model, and include a description and part number from the parts listing.

  • Page 35: Circuit Board Parts

    PWB stands for Printed Wire Board. This is the circuit board only, without components. A6000GTi Power Supply PWA Number: 134174-1 (REV. 6) PWA, A6000GTI SW M PWR CONV Has a flyback low voltage power supply. PWA Number: 134174-1 (REV. 7) PWA, A6000GTI SW M PWR CONV Push-pull low voltage power supply on daughter board mounted where the flyback supply used to be.
  • Page 36 PWA Number: 134230-1(REV. A) PWA, A6000GTI INPUT Initial Release A6000GTI GATE DRIVE (2 PER AMP) PWA Number: 135041-1(REV. A) PWA, A6000GTI GATE DRIVE Initial Release PWA Number: 135041-1(REV. B) PWA, A6000GTI GATE DRIVE Changed Q309 and Q319 to C7448-1. Changed Q301-Q307, Q310-Q317 and Q320 to 125798-1.

  • Page 37: Schematics

    137159-1 Rev. 1 A6000GTi Service Manual 6. Schematics The schematics provided are representative only. There may be slight variations between amplifier to amplifier. These schematics are intended to be used for troubleshooting purposes only. A6000GTi Power Supply A6000GTi Display PWA NUMBER: 134174-1...

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