SUMMARY: Fuzzy monitor

From: Andy Feldt (
Date: Fri Mar 01 1996 - 09:27:48 CST

I originally wrote:

> We have a 19-inch color monitor for a SparcStation 10 which has become less
> clearly focused and is now only marginally usable (yet is critical for one
> group's use). We have attempted to adjust both the horizontal and vertical
> convergence controls (the two controls with three dots and either vertical
> or horizontal parentheses) to no avail. I would have guessed it needed
> de-gaussing, but there is no button to de-gauss! Before we try to scrounge
> up money to bring someone in to repair it (this is a university, so this
> is tough to do!), we thought we'd ask the collective wisdom for help.
> According to the back of the monitor, it is Model GDM-1962B

The short answer is that an internal focus screw must be adjusted and that
it is dangerous for non-trained persons to attempt due to the high voltage
which exists. For a longer summary, see below.

Thanks are due to: (Steve Butterfield)
David Fetrow <> (Perry Hutchison)
Kevin Martinez <>
"Marks, Evan R" <> (David Procter) (Timothy Henrion)
Jay Lessert <>
Mike Coughlin <>

For more details I've appended David Procter's response which covered most
of what everyone recommended.

> Hello Andy,
> Nope, from your description, de-gaussing will not help. That is
> related to uneveness of a colour across the screen. For the record, the
> GDM-1962Bs degauss every time you switch on. You can test this by
> switching the monitor off for a few seconds then on again. A Star
> Trek-like waviness will be apparerent for a few seconds & the monitor
> will be degaussed along with any magnetic media in the vicinity.
> We did not manufacture these beasts here so I'm guessing a bit but
> hopefully you can (read _all_ of this first) :-
> Switch off the monitor.
> Remove the rear cover.
> Identify the High-voltage transformer (has a lead leading to the large
> plastic high-voltage anode cap on the back of the tube).
> There should be some rotatable adjustments on the transformers casing.
> One should be labelled Focus, another Screen.
> Identify a way of accessing the Focus adjustment without touching any other
> part of the monitor.
> Switch on the monitor.
> Display your usual fuzzy picture, then adjust the Focus until you
> (hopefully) have a sharper picture.
> Switch off again and put everything back together.
> NB. There is a risk of electic shock from metallic bits inside the
> monitor. Don't be afraid of looking stupid by covering your arms in
> some insulating material when making the adjustment. Do not work alone.
> Check your site's accident rules. Volunteer someone else.
> IF (big) you have any doubt about this do NOT do it yourself. It's
> only a monitor and it _is_ capable of killing you (as is any mains-powered
> unit with the cover off).
> I won't wish you Good Luck 'cos it's only useful for software debugging.
> David.
> ___________________________________________________________________________
> David Procter Digital Communications Development,
> Sony United Kingdom Ltd.,
> Pencoed Technology Centre,
> Tel: +44 1656 867541/2/0 Pencoed,
> Fax: +44 1656 863914 Mid Glamorgan.
> E-mail: CF35 5HZ. Wales, UK

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