\chapter{Video Monitor Adjustments (VAXstation 2000)}
\setcounter{page}{1}


\section{Introduction}

This chapter describes how to adjust the VR260 monochrome monitor for
its best picture. Alignment and adjustments for MicroVAX 2000's terminals
are not covered in this guide. See the terminal's pocket service guide for
all alignments to MicroVAX 2000's terminals.

\section{VR260 Monochrome Monitor}

Adjustments to the monitor are made with its cover removed. If the monitor's 
cover is not already removed, remove it (\para{3.12.1}) and then
reconnect the power cable and the video cable to the monitor.

FoUow the procedures in order. The success of one adjustment may depend
on the accuracy of preceding checks and adjustments with the exception of
the focus and G2 adjustments.

When the procedure teils you to display a test pattern, enter console mode
(\para{2.2.2}), attach a loopback connector (p/n 29-24795) to the 25-pin
communication port, and then type the appropriate test command listed in
\tabref{4-1}. \tabref{4-1} lists the base video alignment patterns and the test
commands that invoke them.

\begin{tbl}{Base Video Alignment Test Commands}{c l c}
\textbf{Test Command} & \textbf{Test Pattern} & \textbf{Loopback Required} \\
\hline
60	&	Circle cross-hatch		&	X \\
61	&	Screen of all E's		&	\\
62	&	White screen pattern	&	\\
\end{tbl}
\newpage
You will need the followine tools to adjust the VR260 monitor.

\begin{itemize}
\item	Alignment tool (p/n 29-24746-00)
\item	Metric measuring tape (p/n 29-25342)
\end{itemize}

\subsection{Preparations}
\begin{enumerate}
\item	Switch on power to the VR260 monitor and the system.

\item	Set the brightness and contrast controls to their maximum positions (\figref{4-1}).

\item	Wait 30 seconds for the monitor to warm up, then adjust the brightness
		to extinguish the raster.

\item	Adjust the contrast for normal viewing level.
\end{enumerate}

Refer to \figref{4-2} for the adjustment locations on the VR260 monitor.

\newpage

\fig{MA-7567-83}{Brightness and Contrast Controls}
\newpage

\fig{MA-0116-87}{VR260 Infernal Adjustment Locations}
\subsection{Horizontal and Vertical Linearity and Focus
Adjustments}
\begin{enumerate}
\item	Display the circle cross-hatch pattern (TEST 60). If the customer is having 
		problems with text, display the all E's pattern (TEST 61) for a 
		reference check.

\newpage

\item	Adjust the horizontal linearity (UN) (use the hex trimpot) for horizontal
		uniformity of the squares across the display. The display should contain
		32 horizontal squares and fill the screen. Refer to \figref{4-3}.

\fig{MA-0117-87}{Circle Cross-Hatch Display}

\item	Adjust the vertical linearity (VL) (use the flat-bladed trimpot) for vertical
		uniformity of the squares up and down the screen. The display should
		contain 27 vertical squares and fill the screen.

\item	Adjust the focus (use a long handled flat-blade screwdriver) for the best
		vertical/horizontal line sharpness. Check an intersection of the crosshatch 
		pattern that is at least three squares in from any one of the four corners.
\end{enumerate}
\newpage
\subsection{Width, Height, and Centering Adjustments}

\begin{enumerate}
\item	Display the white screen display (TEST 62).

\item	Adjust the brightness so the raster is visible.

\item	Adjust the contrast for normal viewing level.

\item	Adjust horizontal centering (H CENT) (use the flat-blade screwdriver)
		until the raster is centered.

\item	Adjust the horizontal phase (HP) so the video is centered in the raster.

\item	Adjust the brightness to extinguish the raster.

\item	Measure the width of the display with the tape measure as shown in
		\figref{4-4}. The display should have a 334 mm width. Adjust width (use
		the hex trimpot) until the display measures 334 mm across.

\caution{Avoid scratching the screen surface with the metal clip of the tape.
		 Start the measurement at 10 cm (100 mm) as shown below.}

\fig{MA-0756-85}{Width and Height Measurements}
\newpage
\item	Adjust the vertical height (VH) and the vertical centering (VC) so that
		the display touches the top and bottoni edges of the screen at the same
		time.

\item	Measure the height of the display with the tape measure. The display
		should have a 282 mm height. Adjust the vertical height (VH) until the
		display measures 282 mm top to bottom.

\end{enumerate}

\subsection{Rechecklng the Display}

\begin{enumerate}
\item	Display the circle cross-hatch pattern (TEST 60).

\item	Check the vertical and horizontal linearity of the Squares. Readjust if
		needed (\para{4.2.2}, steps 2 and 3).

\item	Check the vertical and horizontal centering, the height, and the width
		of the display. Readjust if needed (\para{4.2.3}).
\end{enumerate}

\subsection{Adjusting Minimum Raster}
\begin{enumerate}
\item	Set the brightness to maximum and the contrast to minimum. A raster
		should be faintly visible.

\item	If no raster is visible, adjust G2 (use a flat-blade screwdriver) until a
		raster is faintly visible.

\item	Adjust the brightness and contrast for normal viewing.
\end{enumerate}

\subsection{Reassembling the VR260 Monitor}

\begin{enumerate}
\item	Switch the System power switch and the monitor power switch off.

\warning{Wait at least 30 seconds after you turn off power to unplug the
		 power cord. Static electricity dissipates for 30 seconds after power is tumed off.}

\item	Disconnect the power cord and the video cable from the monitor.

\item	Reverse the procedure in \para{3.12.1}.
\end{enumerate}
