SUMMARY: focus adjustment on Sun/Hitachi 19" monitor

From: Martin Achilli (
Date: Wed Nov 30 1994 - 04:34:58 CST

Here is my summary after having performed the adjustment.

Unfortunately it isn't just Focus that needs adjusting in my case, although there was a slight improvement. I also adjusted Sub-brightness which is the trimmer next to Focus.
The purpose of Sub-brightness (don't flame me if I am wrong) is to adjust the threshold for the black areas. It basically sets the threshold for the border areas, the signal there should give you black. If you try the adjustment you will understand what I mean.

Now the image is brighter, and a problem with the color balance is more noticeable :-(
Does anyone have the past summary which described how to fix this ? I thought I had it but can't find it. I remember there is a WWW node with all the past summaries in Australia, can someone tell me the home page please.
Below are the replies I received, there are many screws to loosen, but the operation is quite simple and it took me about 10 mins. The important thing to do is to let the monitor warm up before doing adjustments, and to check all areas of the screen (centre and corners) for uniformity of focus.

Thanks to all those who replied:

>From!valdes Mon Nov 28 21:19:05 1994
From: John Valdes <>
Subject: Re: Q:focus adustment on 19" Sun/Hitachi monitor
Date: Mon, 28 Nov 1994 14:16:48 -0600 (CST)
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There's a focus adjustment, but you have to open the casing to get at
it. It's not all that complicated, although there are a lot of screws.
First, power off the monitor (keep the system up), unplug the power and
video cables, remove the plastic cover, and then remove the steel mesh
that's on the top of the cage surrounding the tube (there are a couple of
screws on the back that need to be loosened/removed to do this). After
removing the mesh, you should see the high-voltage transformer (there's a
thick cable that runs from the transformer to the tube). On the
transformer, there is a knob labeled 'focus' which is the knob you want
to adjust. With the case open, plug the video and power cables back in,
and turn on monitor. After letting it warm up for 10-15 min, degauss the
monitor by pressing the degauss button on the back, and then adjust the
focus. To help with this adjustment, I find it useful to bring up an xterm
or commandtool on the screen, resize it to the full size of the monitor,
and fill it with 'E's (using a text editor).

Once the focus is set to your liking, you can power the monitor off,
disconnect the cables and reassemble the monitor.

Note that you should be very careful when doing this adjustment, as
there are high voltages inside the monitor. As long as you're careful,
you shouldn't have an problems.

John Valdes
>From!dcase Mon Nov 28 19:45:09 1994
Date: Mon, 28 Nov 1994 09:57:28 -0800 (PST)
From: David Case <>
To: Martin Achilli <>
Subject: Re: Q:focus adustment on 19" Sun/Hitachi monitor
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  I've opened a bunch of them up and there are lots of color/contrast
controls but, I was unable to find any focus adjustment. If it exsists I
would imagine you would have to remove the whole case. Let me know what
you find as I have a few of them in need of adjustment as well.

                                Thank You,
                                David Case

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* Phone = (408)479-0759 *

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