JBL A6000GTi, Service Manual

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137159-1 Rev. 1 A6000GTi Service Manual

2003 Crown Audio, Inc.
Maintenance 4-12
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. Recommended models are those used at the factory.
Device Requirements Recommended Model
Oscilloscope 500 MHz or greater LeCroy 9354A
Distortion Analyzer THD measurements Audio Precision ATS-1
DC Power Suppy 10-16VDC, 1000A Sorensen
Function Generator Sine Wave, 0-6Vrms out Hewlett-Packard HP 33120A
AC/DC voltmeter DB reading capability Hewlett-Packard HP 34401A
Resistive Loads (1) 4 ohm, 6000 watt; (2)
2 ohm, 3000 watt; (1) 1
ohm, 6000 watt
Figure 4.9 Required Test Equipment
4.6. Electrical Checkout Procedure
The test procedures in this section are used to verify the operation of the amplifier. You
may, however, find these tests helpful in troubleshooting a problem if the problem is not
easily identified.
During each test, the follow conditions are assumed, unless otherwise noted:

Unless otherwise specified, all tests are to be done from 20 to 400Hz with 12.5VDC
supply and 2Ohm loads.

Gain adjusted so a 0.775 volt input signal produces maximum rated output. The
input signal to be used is a sine wave of frequency 100Hz.

DBO turned off, HP Frequency pot adjusted full ccw, Phase adjusted full ccw (0
phase), LP Frequency pot adjusted full cw and DB switch set to 12. Bridge mode.

All measurements will be done using an Audio Precision System One or ATS-1 and
the 22KHz filter enabled.

When testing the amplifier in Parallel Mono Mode , insert a jumper between the
Ch1+ and Ch2+ terminals. Then measure across Ch1+ and Ch1-.

When testing the amplifier in Bridge Mono Mode, measure across Ch1+ to Ch2-.