Related Manuals for QSC 1400
Summarization of Contents
Introduction
Documentation
Details schematics, PCB drawings, parts lists, and assembly drawings for repairs.
Equivalent Parts
Guidance on using QSC-approved components to maintain factory specifications and warranty.
Test Equipment
Lists required and suggested test equipment for amplifier calibration and repair procedures.
Factory Repair
Instructions for returning products for repair, including obtaining a Return Authorization number.
Test & Calibration
Model 1100 Test Procedure
Step-by-step guide for testing and calibrating the Model 1100 amplifier.
Model 1200 Test Procedure
Step-by-step guide for testing and calibrating the Model 1200 amplifier.
Model 1400 Test Procedure
Step-by-step guide for testing and calibrating the Model 1400 amplifier.
Model 1700 Test Procedure
Step-by-step guide for testing and calibrating the Model 1700 amplifier.
Troubleshooting
Current Draw
Identifies symptoms and possible causes for excessive current draw or blown fuses in amplifiers.
Protection, Muting Circuit and Power On/Off Delay
Addresses amplifier lock-ups or incorrect startup/shutdown behavior and associated faults.
Faults with Signal Present
Diagnoses issues when the amplifier passes signal but malfunctions, like output breakup or clipping.
Instability
Covers gain problems, spurious noises, and oscillations, including waveform distortion.
Power Supply and Voltage Rail Balancing
Analyzes uneven power rails and supply issues affecting amplifier performance and current limiting.
Circuit Description
Power Supply
Explains the operation of the amplifier's power supply, including transformer, fan control, and unique features.
Balanced Input Circuit, Gain, & Frequency Limits
Details the differential input stage, signal processing, and frequency response characteristics.
Feedback, Gain Stage, Clip, and Short Circuit Protection
Describes amplifier gain stages, clipping indication, and the short circuit protection mechanism.
Driver Transistors and Crossover Biasing
Explains the role of driver transistors and the process of setting crossover bias for optimal performance.
Complementary Output Transistors
Details the function and arrangement of output transistors and their associated components.
Muting Delay and Thermal Shutdown
Describes the muting delay circuit and thermal shutdown protection mechanism activated by PTC sensors.
Series One Parts List
1100 Series Parts
Lists components for 1100 Input Jack Panel, Chassis, and Main Board assemblies.
1200 Series Parts
Lists components for 1200 Chassis and Main Board assemblies.
1400 Series Parts
Lists components for 1400 Chassis and Main Board assemblies.
1700 Series Parts
Lists components for 1700 Chassis, Ch.1 Main Board, and Ch.2 Main Board assemblies.
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