QSC RMX 1850HD

Technical Service Manual
RMX™ Series
2RU models
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▲ RMX 850
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▲ RMX 1450
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▲ RMX 1850HD
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▲ RMX 2450
*TD-000098-00*
TD-000098-00
Rev. C
QSC Audio Products, LLC
Costa Mesa, CA 92626 USA
www.qscaudio.com

QSC RMX 1850HD Specifications

General

Brand	QSC
Model	RMX 1850HD
Category	Amplifier
Language	English

Summary

Introduction

1.1 Restriction of Hazardous Substances Directive (RoHS)

Details the impact of the EU's RoHS Directive on QSC products and servicing.

1.2 QSC Serial Number Identification

Explains the format and significance of QSC serial numbers for RMX amplifiers.

1.3 Service Bulletin Information

Provides guidance on obtaining and utilizing service bulletins for RMX Series amplifiers.

1.4 The Well-Equipped Service Bench

Lists essential tools and equipment required for servicing RMX amplifiers.

1.5 Working with Surface-Mount Components

Offers techniques and guidance for soldering and desoldering SMT components.

1.6 Series Description

Describes the QSC RMX Series amplifiers, their target market, and models.

1.7 Technical Descriptions and Theory of Operation

Explains the technical aspects and operational principles of RMX amplifiers.

Component Identification and Pinout

Power Supplies

Explains the conventional power supply design and its components.

Audio Circuitry

Details the balanced audio inputs, differential amplifier, and feedback loop.

DC Protection

Covers the DC fault protection mechanisms in the amplifiers.

Class H Operation

Explains the two-step Class H output section for improved efficiency.

Bridged Mono Operation and Protection

Explains bridged mono mode functionality and associated protection circuits.

Troubleshooting: Symptoms, Causes, and Remedies

3.1 Excessive Current Draw Issues

Lists symptoms, causes, and solutions for amplifiers blowing fuses or tripping breakers.

3.2 Protection, Muting, and Delay Problems

Addresses issues with amplifier protection circuits, muting, and turn-on/off delays.

3.3 Faults with Signal Present

Covers problems occurring when the amplifier passes a signal but malfunctions.

3.4 Instability and Distortion Issues

Diagnoses causes of signal distortion, ringing, and general instability.

3.5 Power Supply and Rail Balancing Problems

Troubleshoots issues related to power supply voltage regulation and rail balancing.

RMX Calibration Procedures

4.1 Setting Bias

Provides step-by-step instructions for adjusting the bias settings.

4.2 Setting Positive and Negative Current Limits

Details the process for calibrating current limiting thresholds.

Servicing RMX Amplifiers

5.1 Mechanical Disassembly and Re-assembly Guide

Outlines the procedures for safely taking apart and reassembling RMX amplifiers.

Replacement Parts Lists

6.1 RMX850 Replacement Parts

Lists all part numbers and descriptions for the RMX850 model.

6.2 RMX1450 Replacement Parts

Lists all part numbers and descriptions for the RMX1450 model.

6.3 RMX1850 HD Replacement Parts

Lists all part numbers and descriptions for the RMX1850HD model.

6.4 RMX2450 Replacement Parts

Lists all part numbers and descriptions for the RMX2450 model.

Schematics and Diagrams

7.1 RMX AssemblyDisassembly Diagram 1 of 2 (All Models)

Visual guide for the physical assembly and disassembly of RMX units.

7.2 RMX AssemblyDisassembly Diagram 2 of 2 (All Models)

Visual guide for the physical assembly and disassembly of RMX units.

7.3 RMX850 Schematics and Diagrams

Circuit schematics and diagrams for the RMX850 amplifier.

7.4 RMX1450 Schematics and Diagrams

Circuit schematics and diagrams for the RMX1450 amplifier.

7.5 RMX1850 HD Schematics and Diagrams

Circuit schematics and diagrams for the RMX1850HD amplifier.

7.6 RMX2450 Schematics and Diagrams

Circuit schematics and diagrams for the RMX2450 amplifier.

7.7 RMX Power Transformer Configurations

Illustrates the wiring configurations for RMX power transformers.

7.8 RMX Chassis Wiring Diagrams

Shows the overall chassis wiring for RMX models.