Re: Apple II video problem?

[Polymorph <polymorph69@hotmail.com>]

On Aug 3, 5:49 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> MdntTrain wrote:
> > On Aug 1, 6:34 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
> >>Not laughing, but wondering whether the horizontal hold control
> >>(inside the case) could have made the two cases much more similar...
>
> > I can still try that.  Right now, I have HHold adjusted perfectly
> > centered between the two points of going crazy (losing sync?).  Moving
> > it one way does cause, at one point, the left shift video to suddenly
> > shift more towards the center.. but it was near enough to the "going
> > crazy" spot that I didn't feel secure leaving it there and opted for
> > the middle.   I did not try plugging in the Rev 7 board at that spot
> > to see what happened either.
>
> > What are you thinking?
>
> I'm thinking you have it correctly adjusted at the midpoint.  ;-)
>
> Some monitors have horizontal phase lock loops that respond to
> the average (middle) timing of the horizontal sync pulse, while
> others (digital?) will respond more to the leading edge.  This
> could make the difference in horizontal phase, since the leading-
> edge-to-start-of-window timing is apparently nearly constant across
> models.
>
> -michael
>
> NadaNet file server for Apple II computers!
> Home page:  http://members.aol.com/MJMahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."- Hide quoted text -
>
> - Show quoted text -

I have a different, but similar (I think) problem with one of my IIgs
monitors. It displays a reasonable image, however the whole thing is
on a slight lean. That is, one top corner of the display is slightly
higher than the other (can't remember which right now - I'm at work).

I tried messing with the centering rings inside the case, but gave up
as I couldn't seem to remedy the problem. By turning the centering
rings, I could change the "tiltedness" somewhat, but at the cost of
image quality (colours became separated and image deteriorated
greatly). So I gave up and returned the image to its original state
(or as close as I could get it). I may have actually made it worse
rather than better, as I am sure the image was a bit sharper before I
twiddled with it (maybe its just me be negative though).

Although I resigned myself to the fact that the image would remain on
a slant (and I have kinda got used to it), can anyone suggest
something else that I could try to realign the image? Could it be the
result of some component(s) approaching their used-by dates? Maybe
some ageing capacitors or something?

thanks,
-p