Olson Technology LCD-550x1 User Manual

LCD-550

LOW COST AGILE

TELEVISION DEMODULATOR

INSTRUCTION MANUAL

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025-000345 REV B 8/21/01

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CAUTION!

USE CARE WHEN CHANGING CHANNELS OR MAKING ADJUSTMENTS TO THE

LCD-550 MODULES

These units are very small and they use smaller (and more delicate) components than are normally found in larger
equipment.

The DIP switch levers can be damaged by excessive force. Use a small pointed object to gently move the switch
levers to the required positions.

The rotating controls can be pushed-in and broken if too much force is applied against them. When adjusting these
controls, use caution and an alignment tool in good condition that is a good fit to the control slot.

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INTRODUCTION

The LCD-550 is a small low cost demodulator for use in cable and off-air applications. It is designed to mount
in Olson T echnology’ s LCM-550-RKA rack mountable chassis. The demodulator is shipped as a single LCD-550
and occupies 3 slots in the LCM-550 RKA chassis.

The LCD-550 can be made into a dual demodulator assembly by removing the front panel and guide pin on the
second LCD-550 and installing on top of the first demodulator .

The units have a front panel switch that switches between NTSC broadcast channels and a user defined CA TV
tuning mode. The user can select from 6 NTSC channel plans and frequency tuning.

The units have a single RCA type audio output connector. The type of signal at this connector is selected from
3 types by internal jumpers. The user can choose normal audio, multiplex audio, or subcarrier . RF Input and V ideo

Output connectors are “F” type. See Figure 2 for connector location.

The demods have an LED that indicates low input levels. This LED also flashes with invalid tuning settings.
(LED is labeled “NO VIDEO” on some early models)

INST ALLATION

Units are shipped in the Olson T ech CATV tuning mode with normal audio output. If other settings are
required, go to page 4 for instructions.

Slide the unit into the rack shelf, making sure that the notch on the rear of the unit engages the tab on the shelf.
Install and tighten the front thumb screw .

Connect the Audio and V ideo Output cables and the RF Input cable. Note that the combiner on the rear of
some LCM-550 rack shelves is for outputs, not inputs. It is recommended that units be added with the rack assembly
powered down, but they can be added hot as long as the long ground pin makes contact first. Connect the power
cable(s).

Set the tuning switches to the desired channel. If the unit is driving an LCM-550 with normal audio, no
internal adjustments will be required. See Figure 1 for front panel controls.

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FRONT PANEL CONTROLS

Front panel controls should be adjusted only with plastic alignment tools. Damage may result if metal tools
are used. Refer to the following figure for the location of the front panel controls.

Figure 1

The LOW RF LED turns on with low or missing RF input. It also flashes on invalid tuning or mode settings. All outputs
are squelched with low RF or invalid tuning.

The VIDEO ON dipswitch turns all outputs on and off.

The CA TV -BCST dipswitch changes the tuning mode. In the CA TV position the tuning mode is set by the tuning mode
switch on the top of the demod. The BCST mode tunes NTSC broadcast VHF/UHF channels. This mode is invalid
for all P AL units.

The channel select switches tune the RF input frequency . The set point of these switches is indicated by a small
triangular notch that is perpendicular to the adjustment slot. When tuning by frequency , these switches are the
frequency in MHz, with the .25MHz steps set by the tuning mode switch.

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