shadowy monitor (CRT): any ideas?

On 2 Jul 2003 13:20:40 -0700
jdgill.RemoveThis@juno.com (John Gill) wrote:

 > I would check the electrolytic capacitors on the CRT neck board.
 > Use an ESR meter to check for high internal resistance.
 > Usually the ones marked 1Uf/50V to 160 volts are the ones that
 > go bad. If you don't have an ESR meter I would just replace
 > all these on the board. They are cheap.

Just a comment, but since we don't know if the OP has any electronics
experience I think it worth mentioning that (1) CRTs are large
high vacuum devices--break one and it goes off like a hand
grenade--be careful how you handle it--a certain amount of fear
is better than carelessness, but healthy respect is best, and (2)
monitors store high voltage for a long time--with it unplugged it's not
likely to kill you outright unless you have_really_ bad luck but it can
knock you silly and you may fall or bang into something when you're
recoiling from it--if you bang into the CRT hard enough then you get to
(1). The high voltage is present on the heavy wire that goes into the
side of the CRT and in the components that it attaches to on the other
end--keep clear of those and you should be fine.

I'm not trying to discourage the guy but better safe than
sorry.

 > Hope this helps...
 > John
 >
 > "Jeremy Price" <Jeremy.Price.RemoveThis@btopenworld.com> wrote in message
 > news:<bduj3d$ono$1@hercules.btinternet.com>...
  > > Something seems to have gone horribly wrong with my CRT monitor,
  > > it's a Mitsubishi 720 that's around 4 years old ( and therefore
  > > out of warranty ).
  > >
  > > Any light or dark area of colour now casts a "shadow" right
  > > across the screen from left to right. So a white page with black
  > > text has grey "smudge" lines across it the same height as the text.
  > > A large black area ( e.g. a web page with a black background )
  > > casts a dark grey shadow right across the screen.
  > >
  > > So any opinions of the following would be really welcome:
  > >
  > > 1: is it the monitor that is a fault ( I assume it is, but
  > > you never know ).
  > >
  > > 2: is it worth fixing? ( or is it time to buy a new monitor? )
  > >
  > > Comment from people who sell new monitors maybe taken with a
  > > pinch of salt!
  > > cheers,
  > > Jeremy
  > >
  > >
  > >
  > > ---
  > > Outgoing mail is certified Virus Free.
  > > Checked by AVG anti-virus system (http://www.grisoft.com).
  > > Version: 6.0.487 / Virus Database: 286 - Release Date: 01/06/03


--
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

Maybe monitor's fault, maybe graphics card fault, or may even be the vga
cable. you can try testing them out.

Jeremy Price wrote:
 > Something seems to have gone horribly wrong with my CRT monitor,
 > it's a Mitsubishi 720 that's around 4 years old ( and therefore
 > out of warranty ).
 >
 > Any light or dark area of colour now casts a "shadow" right
 > across the screen from left to right. So a white page with black
 > text has grey "smudge" lines across it the same height as the text.
 > A large black area ( e.g. a web page with a black background )
 > casts a dark grey shadow right across the screen.
 >
 > So any opinions of the following would be really welcome:
 >
 > 1: is it the monitor that is a fault ( I assume it is, but
 > you never know ).
 >
 > 2: is it worth fixing? ( or is it time to buy a new monitor? )
 >
 > Comment from people who sell new monitors maybe taken with a
 > pinch of salt!
 > cheers,
 > Jeremy
 >
 >
 >
 > ---
 > Outgoing mail is certified Virus Free.
 > Checked by AVG anti-virus system (http://www.grisoft.com).
 > Version: 6.0.487 / Virus Database: 286 - Release Date: 01/06/03
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

 > Just a comment, but since we don't know if the OP has any electronics
 > experience I think it worth mentioning that (1) CRTs are large
 > high vacuum devices--break one and it goes off like a hand
 > grenade--be careful how you handle it--a certain amount of fear
 > is better than carelessness, but healthy respect is best, and (2)
 > monitors store high voltage for a long time--with it unplugged it's not
 > likely to kill you outright unless you have_really_ bad luck but it can
 > knock you silly and you may fall or bang into something when you're
 > recoiling from it--if you bang into the CRT hard enough then you get to
 > (1). The high voltage is present on the heavy wire that goes into the
 > side of the CRT and in the components that it attaches to on the other
 > end--keep clear of those and you should be fine.
 >
 > I'm not trying to discourage the guy but better safe than
 > sorry.
 >
  > > Hope this helps...

Oh, really? You obviously havn't vented your anger on a CRT bottle. They are
incredably resistant to exploding. When is the last time you read about a CRT
explosion--never. I tried to "detonate" one and finally gave up after throwing
into an empty dumpster several times--It just bounced around. I finally managed
to break the end of the neck and all I got was a high pitched squeal as the
vacuum was lost. These things are made of tempered glass with a safety shield
bonded to the face. I've seen demos where bullets were fired into them and
nothing but a small hole surrounded by a star pattern break was the consequence.

Regards,

John<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

"JTM" <j DeleteThis @j.com> wrote in message
news:7hhNa.44836$xg5.14351@twister.austin.rr.com...

  > > I'm not trying to discourage the guy but better safe than
  > > sorry.

 > Oh, really? You obviously havn't vented your anger on a CRT bottle. They
are
 > incredably resistant to exploding.

OK, just to inject a little more reality into this....

The truth about CRTs is somewhere between these two. A CRT
IS extremely resistant to "exploding" and scattering glass, at least from
the front - for obvious reasons, CRT safety standards require that they
NOT spray glass all over if they're hit on the faceplate side. Having
said that, though, it IS a very good idea to be cautious around a "bare"
CRT, for pretty much the same reasons as given in the first response.
They are pretty fragile in the neck/funnel area, and if they break there
they have a nasty habit of winding up with some pretty sharp edges.
Also, they ARE just big vacuum tubes, and the inrush of air when the
tube breaks, depending on just where it does break, can scatter some
glass and other particles around - not a good thing, especially if any
of this winds up getting in your eyes. Finally, even if they don't break,
you need to keep in mind that you are dealing with what's basically a
big glass capacitor, and it can retain a healthy charge long after it's been
disconnected from the high voltage supply. A CRT should ALWAYS
be discharged before being handled or worked on/around. Eye protection
and gloves are also strongly recommended at all times. (Oh, and when
carrying a tube, the first natural inclination is to grab it by the neck.
Don't do that. The SECOND natural inclination is to cradle it, screen-
down, with both hands under the screen and the tube resting against
your chest. That's much better, but if you do that, be really careful
where the anode button (HV connection) is, or make SURE it's discharged.
Ask me how I know this....)

However, we should also note that the original question wasn't about a
bare CRT, but a complete monitor - and in that case, it should also be
remembered that there are OTHER sources of hazardous voltages besides
just the tube (although the CRT and its HV connection are certainly one
of the more obvious). The short form answer is that if you're not familiar
with safe procedures when working around high voltage equipment, you
have no business playing around inside a CRT monitor.

Bob M.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

On Mon, 7 Jul 2003 08:59:53 -0600, "Bob Myers"
<nospamplease.RemoveThis@addressinvalid.com> wrote:

 >Ask me how I know this....)

Ouch

Bob I smashed a CRT once when I was a kid, devilment

It took a massive boulder to make it implode and some big ones
bounced off the front

Very dangerous if you touch the undischarged final anode while
you're carrying one - to your feet <!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

Jeremy Price <Jeremy.Price.TakeThisOut@btopenworld.com> kenjka:
 > Something seems to have gone horribly wrong with my CRT monitor,
 > it's a Mitsubishi 720 that's around 4 years old ( and therefore
 > out of warranty ).

 > Any light or dark area of colour now casts a "shadow" right
 > across the screen from left to right. So a white page with black
 > text has grey "smudge" lines across it the same height as the text.
 > A large black area ( e.g. a web page with a black background )
 > casts a dark grey shadow right across the screen.


1) Replace monitor cable...

2) Monitor has got a 'tired-tube' problem, and it is fixable, but only in
some service shops which have some special apparatus for bringing old tubes
to life... But it won't last long after it... Check the cable...


--
"Brezuljkasts li blatou karu ?" upita Hitler oblaci Bobiu slusu.
"Nisam ja nikog bombardiro !" rece uljea ugnjetava "Ja samo kamionog ljubija zutm !" By runf

Damir Lukic, calypso.TakeThisOut@fly.srk.fer.hr
a member of hr.comp.hardver FAQ-team<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

<calypso.TakeThisOut@fly.srk.fer.hr> wrote in message
news:bf9k8o$cq8c7$9@ID-159462.news.uni-berlin.de...

  > > Any light or dark area of colour now casts a "shadow" right
  > > across the screen from left to right. So a white page with black
  > > text has grey "smudge" lines across it the same height as the text.
  > > A large black area ( e.g. a web page with a black background )
  > > casts a dark grey shadow right across the screen.
 >
 >
 > 1) Replace monitor cable...
 >
 > 2) Monitor has got a 'tired-tube' problem, and it is fixable, but only in
 > some service shops which have some special apparatus for bringing old
tubes
 > to life... But it won't last long after it... Check the cable...
 >

The first is extremely unlikely to be the cause, and the second
nearly impossible. This sounds far more like a problem in
the video amplifier. There's little that could happen to the CRT
itself that would cause this sort of a problem.


Bob M.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

Bob Myers <nospamplease RemoveThis @addressinvalid.com> kenjka:
 > The first is extremely unlikely to be the cause, and the second
 > nearly impossible. This sounds far more like a problem in
 > the video amplifier. There's little that could happen to the CRT
 > itself that would cause this sort of a problem.

Look... It's normal troubleshooting for shadows near the text... But, if he
has got some other kind of shadowing, then it's something else...


--
U zraku se za svaku Novu Godinu izbacen paprikau karu.
By runf

Damir Lukic, calypso RemoveThis @fly.srk.fer.hr
a member of hr.comp.hardver FAQ-team<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

<calypso.RemoveThis@fly.srk.fer.hr> wrote in message
news:bfa34d$cml6f$1@ID-159462.news.uni-berlin.de...
 > Bob Myers <nospamplease.RemoveThis@addressinvalid.com> kenjka:
  > > The first is extremely unlikely to be the cause, and the second
  > > nearly impossible. This sounds far more like a problem in
  > > the video amplifier. There's little that could happen to the CRT
  > > itself that would cause this sort of a problem.
 >
 > Look... It's normal troubleshooting for shadows near the text... But, if
he
 > has got some other kind of shadowing, then it's something else...

You have some reason for thinking that the CRT itself can cause
shadows? Please re-read the original problem description.

Bob M.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas? 

Bob Myers <nospamplease.TakeThisOut@addressinvalid.com> kenjka:
 > You have some reason for thinking that the CRT itself can cause
 > shadows? Please re-read the original problem description.

Like I said - tired tube can be the cause... Also, badly terminated VGA
cable too...

But, it's possibilities... I didn't say that it's for sure... And, maybe I
just didn't understand some terms, since I'm not 100% familiar with
English... OK?

NHF...

--
U sumi se navecer sepav lubenicao jebe. By runf

Damir Lukic, calypso.TakeThisOut@fly.srk.fer.hr
a member of hr.comp.hardver FAQ-team<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: shadowy monitor (CRT): any ideas?