Viewsonic PS775 Question

[JH]

I found this Viewsonic PS775 monitor in the to-be-recycled pile at the
office. All the new monitors are LCDs and the old ones are not
necessarily bad when they get rid of them so I thought I would check
it out as a upgrade to a older (early 90s vintage) PC I use
occasionally for CAD work at home. I hooked it up to my fairly new
laptop and it worked although there was a distortion in the screen
about 1-2" down from the top. Like a mild horizontal tear. Got the
same results with my newer desktop that I have a LCD monitor on
normally. OK, figured that was why it was in the pile. Just for the
heck of it I hooked it up to this older PC and it seems perfectly
fine. Why could this be? Different scan freq? Just wondering. It
sure is a improvement over the 13" (I think) monitor on that old PC,
especially for doing CAD work. Why did/does it have this problem in
the first place, bad yoke or some caps someplace?

 

[Haywire1]

I think you're on the right track. My guess would be bad caps someplace
that affects the unit's ability to lock onto certain scan rate(s). Without
a schematic, try an ESR meter, (unplugged, of course) and concentrate around
the vertical deflection area, probing particularly the electrolytics on the
board in areas of high heat (board darkened, browned, etc.) - beg or borrow
one, as buying one for just this unit wouldn't be economical unless you
intend to repair many of these ;-)


"JH" <jhopman@phoeintl.com> wrote in message
news:1adc16b2-89d2-4baa-aa8e-4b77050568f7@m44g2000hsc.googlegroups.com...

I found this Viewsonic PS775 monitor in the to-be-recycled pile at the
office. All the new monitors are LCDs and the old ones are not
necessarily bad when they get rid of them so I thought I would check
it out as a upgrade to a older (early 90s vintage) PC I use
occasionally for CAD work at home. I hooked it up to my fairly new
laptop and it worked although there was a distortion in the screen
about 1-2" down from the top. Like a mild horizontal tear. Got the
same results with my newer desktop that I have a LCD monitor on
normally. OK, figured that was why it was in the pile. Just for the
heck of it I hooked it up to this older PC and it seems perfectly
fine. Why could this be? Different scan freq? Just wondering. It
sure is a improvement over the 13" (I think) monitor on that old PC,
especially for doing CAD work. Why did/does it have this problem in
the first place, bad yoke or some caps someplace?