QSC DCM-1 User Manual

Also see for DCM-1: Specification sheet

Contents

QSC DCM-1 User Manual Manual pdf 13 page image

13Diagnostics Check Button and Indicators: The Diagnostics / Indicator section includes an ex-tremely simple method of verifying proper system operation and performing basic troubleshooting.The Power LED shows whether the DCM unit is on or off.The Input Clip LED is helpful in verifying that the cinema format processor is not over-driving the DCMinput circuitry.The Load Fault indicator is a unique and powerful feature which verifies that signal inputs into theDCM actually make it through the DCM, the DataPort cables, and the amplifier unit all the way to thespeakers, and that the speaker connections are not electrically shorted or open. All of these measure-ments are being performed constantly (without user action) on ALL output channels and any unusualreadings will light the Load Fault LED. If the Load Fault LED is lit, pressing the Diagnostics button(and holding it pressed) will cause the problem channel’s indicator LED to light. This information will letyou inspect the system cabling for that channel and troubleshoot the problem.There are two types of indication: If the PROC LED and AMP LED are on, there is no amplifier detectedat that DCM amplifier connector. If the AMP LED is on, the amplifier on at that output is measuring ashort or an open on its output terminals.REMEMBER: If you configured the DCM Manager software to not have certain channels (for examplethere is no SUB 3 or SUB 4) or have not assigned a QSC amplifier to a channel, these channels WILLNOT indicate any faults.HARDWARE DESCRIPTION- Front PanelFRONT PANEL (continued)LOAD FAULT INDICATOR NOTE: The DCM’s Load Fault detection scheme uses a complexaveraging algorithm which compares input signals to output signals and measures voltage andcurrent on all amplifier outputs. To sense real world conditions, these measurements must befound to be “out of range” many times before the Load Fault condition is indicated on the frontpanel. If you are simulating fault conditions, you MUST have a “real-world” signal levelthrough the device (full signal input), and the fault condition must exist for several minutesbefore the front panel Load Fault LED will light. This extra fault verification time eliminatesfalse triggering which would be confusing to a user. In conclusion,Just shorting the outputterminals will NOT cause the fault LED to light, the unit must be driven by real-world inputsignals and the fault must persist for several minutes.