LES 780iR Classroom Amplification System Components:
Power Supply
SR-70 Infrared Sensor Cable
SR-70 Infrared Sensor
Various speakers are available and are
typically shipped in a separate box with
plenum-rated speaker wire.
RCA Cables
Speaker(s)
LES 780iR Receiver/Amplifier
Troubleshooting Guide
Please go through this checklist before calling
LightSPEED Service Department.
Battery Check:
• Confirm batteries are charged each
night. With proper charging,
batteries will last about one
school year.
• Transmitters are charged via a
jumper cable from the back of the
LES 780iR. Make sure plugs are
secured and in the proper jacks.
• Confirm the green charging light
located on the front of the LightMic
is on while charging.
• Ensure the LightMic is turned off
while charging.
Hearing Static or Buzzing:
• If using two LightMics, check that
they are not set to the same
channel. If so, select a different
channel for one of the LightMics.
• Keep the LES 780iR at least 6 feet
away from computers.
Low Volume:
• Check volume level on the LES
780iR and adjust as necessary.
• Check volume level on each of the
speakers (on back panel) and adjust
as necessary.
Sound Fades In and Out
(Drop Out):
• Test LightMic with fully charged
batteries. LED light on front of mic
will glow bright red.
No Sound From Speaker:
• Confirm the LightMic and the
LES 780iR are turned on and have
matching channels. Check both
A VOLUME and B VOLUME
to ensure they are set correctly.
• Confirm amplifier power supply is
the correct type—if in doubt, call
LightSPEED. In addition, confirm
that the power supply is connected
securely in the wall outlet and into
the DC POWER connector
on the back of the 780iR.
• Turn the 780iR on. Confirm that
the POWER light located on the
front panel switch is on.
• Turn the LightMic on and confirm
that the corresponding red IR light,
located on the front panel of the
LES 780iR, lights. When speaking
into the LightMic, the green AF
light will flash/flutter with your
voice volume.
• Confirm that the batteries in the
transmitter are fully charged. When
they are, the red indicator will
glow steadily.
• Confirm that the speaker wires are
in the correct jacks on the back of
the LES 780iR and confirm that the
speaker switch for that speaker
output is in the ON position. Also,
confirm that the volume level for
each connected speaker is set in the
middle position (12 o’clock).
LT-70 LightMic
™
Microphone/Transmitter
[2]
[17]
