Olson Technology LCM-500-550 - Manual (Page 5)

025-000181 REV C Page 5
5) AUDIO MODULATION ADJUSTMENT
A) Connect an audio source of 300mv p-p (minimum) to the input connector (10K ohms input Z) on the
rear panel.
B) Rotate the audio modulation (MOD) control slowly clockwise until the audio overmodulation light (O/
M) just begins to blink. CAUTION: Overmodulation can result in severe distortion in some TV sets.
Set this control at peak program levels.
6) RF OUTPUT AND AURAL CARRIER LEVEL ADJUSTMENT
A) Using a field strength meter or spectrum analyzer, set the video carrier to the desired level with the RF
output “level” adjust pot (typically +55dBmV).
B) Tune the field strength meter to the aural carrier, which is located 4.5MHz above the video carrier.
C) Adjust the aural carrier level control (A/V) to the desired level, typically 15dB below the video carrier.
CAUTION: Reducing the visual/aural carrier ratio to less than 15dB can result in high out-of-band
spurious signals in adjacent channels.
7) MISCELLANEOUS
A) The LCM-500-550 is BTSC stereo compatible. It is shipped in the “mono” mode. To defeat the pre-
emphasis, in order to use a composite baseband BTSC input signal, move the internal jumper plug
from W-6 “PRE” to W-6 “BY”. This plug is located on the right side of P.C. board.
B) When installing this unit in an equipment rack, it is best to leave an empty rack space above and below
this unit to allow for optimum air circulation.
C) The LCM-500-550 is equipped with a 0.5A slo-blo fuse. For continued safety, and to maintain
proper performance of the unit, please replace only with an equivalent fuse.