QSC 3800 Service Manual

Series III
Power Amplifiers
TECHNICAL SERVICE MANUAL
 3800
REV. B
*TD-300001-AX*
 3500
 3350

3200

QSC 3800 Specifications

Output Power

output power 16 ohms	720 watts
output power 8 ohms	375 watts
output power 4 ohms	600 watts
output power 2 ohms	850 watts

Frequency Response

frequency response 8 ohms	20–20kHz, ±0.1dB
frequency response 4 ohms	8–300kHz, +0/-3dB

Power

power requirements	120, 220, or 240V 50–60 Hz, 13A (each channel)
power gain 8 ohms	65.5 dB
dynamic headroom 4 ohms	2dB

Weight and Dimensions

weight	75 Ib
faceplate dimensions	19"x5.25"
depth	17.9"

Summary

Circuit Description

Block Diagram

Detailed Explanations

Troubleshooting Chart

Current Draw Section

Diagnosing issues related to excessive current draw.

Protection Circuit Problems

Troubleshooting issues with protection circuits.

Relay Faults

Diagnosing problems with the output relay.

Faults With Signal Present

Identifying issues when signal is present but not correct.

Unstable and Wrong Current Limits

Addressing instability and incorrect current limits.

Step Problems and Excess Distortion

Troubleshooting step issues and excess distortion.

Crossover and Step Distortion

Diagnosing crossover and step-related distortion.

General Distortion and Gain Issues

Resolving general distortion and gain problems.

Test Procedures

Model 3200 Test Procedures

Model 3350 Test Procedures

Model 3500 Test Procedures

Model 3800 Test Procedures

Series Three Schematics

Model 3200 Schematic

Model 3350 Schematic

Model 3500 Schematics

Model 3800 Schematic