Browse Prior Art Database

Factory Override of Operator Brightness Control for CRT Visual Display Terminals

IP.com Disclosure Number: IPCOM000101720D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Santitoro, RT: AUTHOR [+2]

Abstract

Disclosed is a circuit for automatically overriding the operator brightness control of a CRT visual display terminal (VDT) during the manufacturing set-up process.

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Factory Override of Operator Brightness Control for CRT Visual Display Terminals

       Disclosed is a circuit for automatically overriding the
operator brightness control of a CRT visual display terminal (VDT)
during the manufacturing set-up process.

      The typical manufacturing set-up process for a CRT VDT demands
that during certain parts of the process the operator brightness
control knob be adjusted to a known state.  By controlling this
adjustment electronically, a manual check of the adjustment in an
otherwise automatic procedure can be eliminated.  This results in a
greater process throughput and increases the level of quality by
eliminating the potential for errors due to human intervention.

      Using the disclosed circuit, the operator brightness control
can be forced to a fully on position (maximum brightness) or a fully
off position (minimum brightness). The other allowed condition
disables the circuit for normal brightness operation (see the table).
This is the state that the circuit remains in after manufacture.

      With reference to the figure, R1, R2 and R3 comprise the
operator brightness control of the terminal.  R4 and R5 provide
terminating resistance for the transistor bases.  R6 provides short
circuit protection during the switching transition and also in the
event that the not-allowed state is unintentionally invoked.