From: cs4w+@andrew.cmu.edu (Charles William Swiger)
Newsgroups: comp.sys.next.hardware
Subject: Re: Third party servicing place for fixing 17" mono monitor
Date: 6 Oct 92 07:15:16 GMT
Article-I.D.: andrew.AeoOq4m00WB0MdE1IW
Distribution: na
Organization: Senior, Chemistry, Carnegie Mellon, Pittsburgh, PA

If you feel brave, you can probably perform the necessary adjustments yourself.

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I have adjusted several monitors with no problems, but make sure you
know what you are doing before opening anything.  I expressly disclaim
responsibility for any ill results that may occur.

In order to adjust NeXT's MegaPixel display (called 'the monitor'
hereafter), you'll need (a) the NeXTtool (or an Allen wrench), (b) a
plastic adjustment tool (preferred) or a thin bladed screwdriver, and
possibly (c) a Phillips-head screwdriver.

(NB: A similar procedure will work for color monitors, but you should
either know what you're doing or you'll probably be better off letting a
pro deal with it.)

Turn off the computer.  Disconnect all cables to the monitor.  Look at
the back of the monitor.  There will be 4 screws there; use the NeXTtool
(or Allen wrench) to remove them.  Remove the plastic back of the
monitor and put it out of your way.

Reconnect the cables and turn the computer back on.  As the machine
powers up, examine the back of the monitor.  You'll see a metallic box
(usually silver, though some are black) surrounding the monitor's
vitals.  This protects you against the dangerous voltages inside, and
also insulates the monitor from electromagnetic noise.  On the back of
this box are several holes for performing adjustments.  There are two
focus controls (labelled 'focus' and 'dynamic focus'), a brightness
control (labelled 'brightness' or possibly 'black level') and several
other that adjust various things like screen size and position.

Depending on the exact placement of the controls on the circuit board of
your specific monitor, some of these controls may be difficult (or
impossible) to adjust from the back.  If this is the case, I will
describe what's necessary below.  Otherwise, adjust the appropriate
controls using either an adjustment tool or a screwdriver.  Be warned
that a screwdriver probably will cause some interesting video effects
when it enters the case.  Ignore this the best you can, or find a
plastic adjustment tool, which is what you *really* should be using
anyway.  Using a flashlight will help you see into the hole so that you
can align the business end of the tool correctly.

Focus and position controls are fairly obvious.  Adjust them slowly
until you're happy with the results.  Don't muck with anything you don't
need to; the factory settings are usally pretty decent.

To correctly adjust the brightness, follow this procedure: Turn the
brightness of the monitor all the way down using the keyboard.  Adjust
the brightness control on the back of the monitor until a barely
noticeable picture forms.  Then turn the brightness down a little so
this picture disappears completely.  Check that you can get adequete
brightness by using the keyboard to brighten the screen.  If the display
isn't bright enough, adjust the brightness control on the rear of the
monitor high enough so that the monitor display is adequate.  Note that
you won't be able to dim the screen completely from the keyboard...sorry.

Once you're finished, shut down the computer, take off the cables,
reattach the back of the monitor, and reconnect the cables.  You're done.

If the control you need to adjust proves to be difficult, you may need
to enter the metal case.  This happened on one monitor's focus control
and another's brightness.

WARNING:  THE VOLTAGES INSIDE THE MONITOR'S CASE ARE VERY DANGEROUS,
EVEN WHEN THE MONITOR IS OFF.  BE VERY CAREFUL, OR YOU CAN SERIOUSLY
INJURE OR EVEN KILL YOURSELF.  Do not perform the next instructions
unless you are confident that you know what you are doing.

You'll have to power off the computer again, and disconnect the cables.

Looking at the monitor from the back, notice a section of metallic
shielding on the right side of the metal box that extends to the picture
tube.  This is where the flyback tranformer is connected.  It shields a
wire that is charged to about 25,000 V.  DO NOT TOUCH THIS WIRE, IT CAN
SHOCK YOU THROUGH ITS INSULATION.  Being very careful of this, remove
the metal case by unscrewing the Philip's head screws that hold the case
on.  Don't touch the screws that hold the picture tube into the front of
the monitor's case.

Once you've gotten the metal box off, reconnect the cables.  Figure out
what control you're going to adjust, and make sure that you can do so
without touching anything else inside.  Again, *watch out* for the wire
that connects to the picture tube on the right side.

Power up the computer.  I recommend that you use only one hand to make
the adjustment, and that your other hand be placed in your pocket (or
similar equivalent, if you're wearing clothes lacking pockets).  This
precaution reduces the chances that you'll make a short circuit between
one hand, your heart, and the other hand-- a good idea.  Perform the
necessary adjustment(s), being very careful not to touch anything
inside.  Then shut down and reassemble the monitor, following the
directions given above.

Hopefully, these instructions will prove useful.  Once again, please be
very careful...I don't want your death and/or injury on my conscience
(or a lawsuit, for that matter, either :-)

Later,

-Chuck

+---------------------------------------------+ 
|  Charles William Swiger -- CMU sucks rocks  | "The television screen is the
|   AMS & normal mail: cs4w+@andrew.cmu.edu   | retina of the mind's eye."
|    NeXTmail: <temporarily out of order>     |           
+---------------------------------------------+            --Videodrome
Newsgroups: comp.sys.next.hardware