Re: Monitor Question

[Rubywand <rubywand@swbell.net>]

D. Lee writes ...
> 
> Hi,
> 
>         After nearly 14 years of service, my trusty Monitor III connected
> to my Apple IIe is beginning to show signs of wear and tear.
> 
>         The monitor brightness level has been dimming quite a bit lately
> and at times (like right now while I am typing), the stuff displayed on
> the monitor is noticeably flickering.
> 
>         Some questions about the monitor:
> 
> 1.  Is there anything I can do, short of purchasing a new monitor??
>

     Lots of things can cause flicker. A "dirty" control could be slipping 
between a correct setting (e.g. some moderate resistance value) and 'open' 
(e.g. a very high R). It could, even, have developed weak spots and burns 
in the resistance element. Good suspects include the Brightness, 
"Intensity", and "Contrast" controls. If flicker relates, partly, to size 
changes, suspects are "Vertical Lin", "Vertical Size", ..., and "Horizontal 
Hold", ... . Squirting some Control Cleaner into the control-- i.e. into 
the potentiometer or switch-- and turning the control back and forth may 
improve contact and eliminate the flicker.

     Another cause of flicker is arcing from a high-voltage line or the HV 
module to some metal brace or other point inside the monitor. This is, 
usually, related to the build-up of dust and gunk. (You may be able to hear 
popping inside the monitor which coincides with flicker.)  Removing the 
case and giving things a good cleaning plus coating metal surfaces anywhere 
near a HV area with anti-arcing dope may help.

NOTE: Removing the case is kind of hazardous. Work on a non-conducting 
table cleared of obstructions. Any time you remove the case be sure to Wear 
Goggles. The monitor should have been OFF and unplugged for a day-- even 
so, there is always a shock hazard. Avoid bonking, banging, or stressing 
the CRT's neck. Keep heavy tools away from the CRT. In short, if you have 
not cleaned a monitor before, you may want to get it done by someone with 
some experience while you watch.
         

 
> 2.  Is it "dangerous" to be using a monitor that is flickering a lot?.
> I'm afraid it'll hurt my eyes in some way.
>

     There is some concern about radiation. I do not know whether or not 
there is any added radiation hazard connected with abrupt intensity 
changes. Otherwise, flicker may be associated with headaches and, for some 
persons, may trigger siezures.

     14 years is a pretty decent service life. If you do not get the 
problem fixed fairly soon, scrap the monitor.


Rubywand