Free: broken but possibly fixable sync-on-green monitor

[Scott Stevens]

On Mon, 2 May 2005 18:55:08 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:

> > I have a Viewsonic PT813 21" CRT monitor, a very high-end
> > professional model that I was told used to cost $1800 new (1997),
> > has both DE15 and BNC inputs and supports both PeeCee video and sync
> > on green.  Unfortunately it is malfunctioning - the picture is
> > smudged to the point of being totally unreadable.  It seems like
> > some component in its circuitry went bad - I don't think it's the
> > CRT - so it's probably fixable.
> 
> A word of warning to anyone who gets this... I had an Apple Mac+ that
> had a smeared display -- shaddows to the right of objects on the
> screen. Now, the Mac+ video circuit is pretty simple, but
> none-the-less I spent quite a time going through it, unable to find
> the fault.
> 
> The reason I couldn't find a fault in the video amplifier was that
> there wasn't one. It was the CRT. Low emission, I think. 
> 

The CRT on a Mac Plus is probably one of the easiest video tubes to
replace.  It's nice and small, and it's not many screws to get a Plus
apart enough to swap it.  I'm not sure that (used) replacement CRTs are
as plentiful as they were five years ago when I replaced one, though. 
There used to be Apple-oriented 'scrap' shops where you could get a
pulled tube for ten dollars.