Olson Technology LCM-500-550-BG - Manual (Page 3)

025-000237 REV B Page 3
3) OFFSET ADJUSTMENT
To adjust the frequency of a selected channel to provide an offset, remove the video input and connect a
counter to the RF output of the LCM-500-550 B/G. Use the offset adjust control (marked OA) behind the
cover plate to set the output frequency to the desired value.
4) VIDEO MODULATION ADJUSTMENT
A) Connect a video source of approximately 1v p-p to the video input connector (75 ohms input Z) on
the rear panel. The video should be of a reasonably bright scene (commercials are usually excellent).
B) Rotate the video modulation control (MOD) slowly clockwise until the video overmodulation light
(O/M) just turns on. The light may blink with differences in average picture level. CAUTION: If the
modulation is set too high, compression or lack of contrast will occur during high intensity scenes.
5) AUDIO MODULATION ADJUSTMENT
A) Connect an audio source of 500mv 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 +40dBmV).
B) Tune the field strength meter to the aural carrier, which is located 5.5MHz 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 B/G is equipped with a 0.25A slo-blo fuse. For continued safety, and to maintain
proper performance of the unit, please replace only with an equivalent fuse.
B) When installing the LCM-500-550 B/G in an equipment rack, it is best to leave an empty rack space
above and below the unit to allow for optimum air circulation.