Troubleshooting - Lectrosonics UM400AV Instruction Manual

Troubleshooting

Before going through the following chart, be sure that you have a good battery in the transmitter. It is important that
you follow these steps in the sequence listed.
Symptom
TRANSMITTER BATTERY LED OFF
NO TRANSMITTER MODULATION LEDs
RECEIVER RF LAMP OFF
NO SOUND (OR LOW SOUND LEVEL),
RECEIVER INDICATES PROPER AUDIO
MODULATION
DISTORTED SOUND
HISS AND NOISE -- AUDIBLE DROPOUTS
EXCESSIVE FEEDBACK
Rio Rancho, NM
Frequency Synthesized UHF Belt-Pack Transmitter
Possible Cause
1) Battery is inserted backwards.
2) Battery is dead.
1) Gain control turned all the way down.
2) Battery is in backwards. Check power LED.
3) Mic capsule is damaged or malfunctioning.
4) Mic cable damaged or mis-wired.
1) Transmitter not turned on.
2) Transmitter battery is dead.
3) Receiver antenna missing or improperly positioned.
4) Transmitter and receiver not on same frequency. Check
switches/display on transmitter and receiver.
5) Operating range is too great.
6) Transmitter antenna not connected
1) Receiver output level set too low.
2) Receiver output is disconnected; cable is defective
or mis-wired.
3) Sound system or recorder input is turned down.
1) Transmitter gain (audio level) is far too high. Check mod level
lamps on transmitter and receiver as it is being used.
(Refer to Operating Instructions - Adjusting Gain)
2) Receiver output may be mismatched with the sound system or
recorder input. Adjust output level on receiver to the correct
level for the recorder, mixer or sound system.
3) Excessive wind noise or breath "pops." Reposition microphone
and/or use a larger windscreen.
4) Transmitter is not set to same frequency as receiver. Check that
frequency select switches on receiver and transmitter match.
1) Transmitter gain (audio level) far too low.
2) Receiver antenna missing or obstructed.
3) Transmitter antenna missing or folded against housing.
4) Operating range too great.
1) Transmitter gain (audio level) too high. Check gain adjustment
and/or reduce receiver output level.
2) Transmitter too close to speaker system.
3) Mic is too far from user's mouth.
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