PCM-2 Manual.pdf - Voss Associates

Section 15
Traffic Light Board
General Description
The Traffic Light Board consists of six series LED lights (3 red and 3 green) and
six limiting resistor pairs which are controlled by the PCM-2 Front Panel Board.
Switch to ground at Pin 4 on 11 turns on the 3 green lights and switch to ground
at Pin 5 on 11 turns on the 3 red lights. Two Traffic Light PCBA's are mounted
in the ceiling of the PCM-2 behind the two coincident obround cutout sets in the
ceiling trim at the front and left sides of the unit. The red lights are illuminated
whenever the instrument is in its Test Mode or is experiencing a failure in its
Operational Mode (i.e. out of gas, high background fail, sensitivity fail, etc.) and,
thereby, serve as a visual prompt that the unit is not ready for measurement. The
green lights are, conversely, illuminated whenever the unit is ready for
measurement.
Traffic Light Board Parts List
The following table lists the electronic items incorporated in the Traffic Light
Board and should contain any part necessary for normal repair. Unless otherwise
specified, callouts of manufacturers or manufacturers' part numbers are to be
considered typical examples only and not restrictions against using equivalent
parts with the same operating characteristics. When ordering parts from Eberline,
specify model number, serial number, reference designator, value, Eberline part
number, or a word description if the part has no reference designation. Eberline
will automatically substitute equivalent parts when one called out by the
manufacturers' part number is not available,
PCM2.MANI REV AI Arril 1 qq