Troubleshooting Techniques

It’s going to be a great presentation. The students seem excited about the topic and the guest speaker. You decide to get to the church early to make sure everything is working and in order. You step up to the lectern and talk into the microphone (caution: don’t blow into it). Nothing. No sound. PANIC starts. A drop of sweat appears on your forehead as you imagine what chaos will occur if the sound system doesn’t work. STOP. Take a deep breath. You CAN often find the problem yourself. Don’t forget that most problems are caused by a bad cable, poor connections, or simply human error. All you need to do is systematically and logically troubleshoot your system in order to determine where the fault lies. Then you can correct it if possible, or work around the problem.

First of all, you must stop and collect your thoughts. Now is the time to check for three basic possibilities. One - make sure the sound system power switch is on. If your microphone requires phantom power, make sure the phantom power switch is turned on. Two - check to see if the microphone switch is on (if it has one.) And three - determine if the proper volume control is turned on. Also, make sure the master volume control is at the normal setting.

OK, so these are fine and you still don’t have any sound. Now it’s time to find out if other microphones work. Let’s assume you determine the microphone for the panel discussion works fine. You now can breathe easier because you know the main system is working. But you don’t know what is causing the problem with the lectern microphone. It could be the microphone, the portable cable, the installed permanent microphone cable or connectors, or the input channel on the mixer/amplifier. Figure 1 shows a simple flow chart where connection problems could occur.

Figure 1
Connector Problem Spots

The problem can be isolated by substituting a suspected bad component with a known good component. Take the suspected lectern microphone and disconnect it from its cable. Plug the lectern microphone into the known good microphone cable from the previously tested panel microphone. If the lectern microphone still doesn’t work, you can probably assume it is bad. If it does work, you have eliminated the lectern microphone as the source of the problem.

Let’s say the lectern microphone worked. Now try the portable cable that was first connected to the lectern microphone. Cables are always the greatest source of problems in any system. (Taking care of your cables will help keep problems to a minimum.) Again, substitute the suspected cable with a known good cable. If you now get sound, EUREKA! Problem solved. Gently move and twist the cable and connectors to make sure you don’t have an intermittent connection. Perhaps the problem was a poor connection caused by contact oxidation or some dirt. Just plugging and unplugging can help clean the connector contacts.

What if the lectern microphone cable still does not work? It could be the microphone jack on the platform. It may be broken, have dirty or corroded contacts, or the microphone cable wires may be broken off. This probably cannot be fixed immediately, so now plug the lectern cable into another jack and use a different input on the mixer (hopefully you have a spare input).

So what if everything appears good all the way back to the mixer? Try plugging the suspected bad cable into a known good input on the mixer. If it works, then it appears that the mixer has a bad input channel. Time to call us for service. The connectors or the installed microphone cable may be damaged.

What happens if you don’t get sound from any microphone? Again, make sure that all the equipment is plugged into power and turned on. Are all the indicator lights on? Check to make sure all the connectors are completely plugged in. Check the controls and switches - are they in the proper positions?

If you still do not have any sound, it may be possible that you have faulty equipment. This is a reason to call a service person for help. You can now share with the service person the trouble-shooting you did, and that will help the service person to know how to prepare.

By going through these steps, you may eliminate unnecessary repair service and expense. (It can also be embarrassing to have the service person plug in your amplifier!) You will often be able to get that lectern microphone working again by yourself and avoid a sound disaster.

Good troubleshooting!

by Ron Huisinga © 1996 Internet Sound Institute (www.soundinstitute.com). This article is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com

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