Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!samsung!munnari.oz.au!goanna!dnl
From: dnl@goanna.cs.rmit.oz.au (David "IGOR" Latter)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Portrait Display problem
Summary: magnetised screen?
Message-ID: <3979@goanna.cs.rmit.oz.au>
Date: 15 Oct 90 06:57:53 GMT
References: <1990Oct9.210021.24473@Neon.Stanford.EDU> <269@sc2a.unige.ch>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 39


 >>I have an Apple Portrait Display (fancy name for A4/full page). The
 >>general display quality is good, but there is a downward slope at the
 > .
 > .
 >>anyone know what the problem is and how to fix it?
 >>--
 >>* horizontal lines come out looking like this:
 >>    _______
 >>   /
 >> /
 >>/


> > problem.  I also have a Portrait display and noticed a wicked squeal.
> > 

> At our institute, we have one Apple A4 monitor who makes this (upper left
> corner):   :
>             :
>              :
>              :
------------

Has anyone tried to de-magnetise the screen ???
I know that you normally only de-gause on colour tube (I normally service tv's)
however, I have seen the metal mounts on terminals become magnetised which
produces effects as described above.....notably only at the corners where
the metal mounts are....
See if you can find someone with a de-gausing wand.

If it was a tv with a loud "squeal" or ringing...(at line scan rate)
I normally identify the offending ferrite core (eht transformer,switch mode
transformer etc) by pressing on the ferrite with a plastic rod. The noise
stops when you get the right one....To fix it, use some spray poly-urethane
and spray the ferrite.... This when dry locks the ferrite to the windings
and the transformer mounts.