Viewsonic monitor problem

[Tim]

Greetings,

I have g771 viewsonic monitor. It has been working fine until
just recently. When I cleaned the screen, it looks like it
still has dust on it. I have snooped about the web and in the
newsgroups trying to figure out what is going on.

The G771 is a 17" flat screen monitor from 1998. It appears
to have a flat glass screen treated with an anti-glare
substance in front of the crt face. When I use the monitor's
controls to change the view area size, I end up with a white
border around the 'dusty' area. Peering into the corners and
thru the screen with a flashlight, it appears that there is a
gap between the screen and crt face of perhaps as much as 1/4
of an inch; and that the crt face has dust on it. Perhaps the
seal between the screen and the crt face has deteriorated.

I am wondering if it possible to fix this situation. I can
not find a service manual which addresses the way the tube and
screen are joined. I had read somewhere that the two are
sealed and can be held in place by a steel band, which band is
not supposed to be fiddled with.

I would appreciate any thoughts folk might have. The monitor
works just fine, and with new nvidia drivers for the video
card seems to have regained any lost sharpness, etc.

Thanks in advance.

Be well,

Tim

Old system: <s&g>
Gigabyte G7xe
Duron 1000mhz
500 meg memory
GeForce4 MX 4000
Silicon Image pci ide controller
5 Western Digital hard drives

 

[GT]

Greetings,

I have g771 viewsonic monitor. It has been working fine until
just recently. When I cleaned the screen, it looks like it
still has dust on it. I have snooped about the web and in the
newsgroups trying to figure out what is going on.

The G771 is a 17" flat screen monitor from 1998. It appears
to have a flat glass screen treated with an anti-glare
substance in front of the crt face. When I use the monitor's
controls to change the view area size, I end up with a white
border around the 'dusty' area. Peering into the corners and
thru the screen with a flashlight, it appears that there is a
gap between the screen and crt face of perhaps as much as 1/4
of an inch; and that the crt face has dust on it. Perhaps the
seal between the screen and the crt face has deteriorated.

I am wondering if it possible to fix this situation. I can
not find a service manual which addresses the way the tube and
screen are joined. I had read somewhere that the two are
sealed and can be held in place by a steel band, which band is
not supposed to be fiddled with.

I would appreciate any thoughts folk might have. The monitor
works just fine, and with new nvidia drivers for the video
card seems to have regained any lost sharpness, etc.

2 things: If you take the monitor apart, leave it to rest for a while before
going near it. A very high voltage builds up on there and it takes a while
to dissipate. If you touch the wrong part, you will blow yourself out of the
building!

Secondly, you have confused me with your last statement - "The monitor works
just fine... ... with new nvidia drivers for the video card seems to have
regained any lost sharpness". If this is true, then what problem remains?

 

[kony]

I am wondering if it possible to fix this situation. I can
not find a service manual which addresses the way the tube and
screen are joined. I had read somewhere that the two are
sealed and can be held in place by a steel band, which band is
not supposed to be fiddled with.

Yes it's often a band holding it in, and it isn't supposed
to be fiddled with because you aren't supposed to take apart
a monitor... but if there really is dust between the tube
face and an outer glass sheet then that is what would be
necessary to do.

However, I think you should consider that this monitor is
now 10 years old and ready to be replaced instead of a lot
of work for a monitor ready to die of old age.

 

[Tim]

2 things: If you take the monitor apart, leave it to rest
for a while before going near it. A very high voltage
builds up on there and it takes a while to dissipate. If
you touch the wrong part, you will blow yourself out of the
building!

Secondly, you have confused me with your last statement -
"The monitor works just fine... ... with new nvidia drivers
for the video card seems to have regained any lost
sharpness". If this is true, then what problem remains?

Greetings GT,

Believe me that I do not want to fiddle with the innards! I was
just hoping someone would know if there was a simple seal
between the screen and the crt tube which could be
fixed/replaced after cleaning the crt tube surface. For as it
is now, there is what appears to be a dust layer between the
screen and the crt tube which gives a very light grayish-
brownish caste to everything.

Thanks for the reply.

Be well,

Tim

 

[Tim]

Yes it's often a band holding it in, and it isn't supposed
to be fiddled with because you aren't supposed to take
apart a monitor... but if there really is dust between the
tube face and an outer glass sheet then that is what would
be necessary to do.

However, I think you should consider that this monitor is
now 10 years old and ready to be replaced instead of a lot
of work for a monitor ready to die of old age.

Greetings,

I do agree with you in general. The beast is going to be ten
in 6 months. Just hoping to defer the dollar outlay for a bit
.... <s&g>.

Is there any risk that the steel band has become loose - hence
the infiltration - and that the case is actually
holding/reinforcing the tube? Not too excited about pulling
the front of the case off if this were to be the case.

Thanks for the reply.

Be well,

Tim

 

[kony]

Believe me that I do not want to fiddle with the innards! I was
just hoping someone would know if there was a simple seal
between the screen and the crt tube which could be
fixed/replaced after cleaning the crt tube surface. For as it
is now, there is what appears to be a dust layer between the
screen and the crt tube which gives a very light grayish-
brownish caste to everything.

I would suspect there is nothing sealing the two and that is
why dust eventually got in... but to know for sure you'd
have to start taking it apart. I caution you to first
Google for a safe method of discharging the tube, it will
hold a high voltage charge for awhile, though I don't know
how many days.

I suppose it could instead be that there was a seal like
foam and it just deteriorated over the years and this "dust"
you see is actually particles off the seal.

 

[kony]

kony <[email protected]> wrote on 11 Jan 2008

I do agree with you in general. The beast is going to be ten
in 6 months. Just hoping to defer the dollar outlay for a bit
... <s&g>.

Is there any risk that the steel band has become loose - hence
the infiltration - and that the case is actually
holding/reinforcing the tube? Not too excited about pulling
the front of the case off if this were to be the case.

I doubt the band became loose, but I can't say it even has
one for certain nor if it did, that this is the cause.
You'd just have to open it and see for yourself.

The case front frame does hold the tube in a *normal* design
(I can't swear 100% of them are like this but offhand I
can't think of any other way it'd be done). The tube needs
no reinforcement but does need the rear board pulled off
carefully so as to not damage it, and the whole think
sitting on the tube/case front so it's sticking straight up
in the air. I'm only giving a brief overview, this is
really beyond the scope of a usenet post, you'd be taking
the whole tube out, cleaning and reassembling later - it is
not a 15 minute job. If there is no seal there is every
reason to think it will get dusty again. If there is a seal
it has degraded to not perform the function and it is not
likely the band holding the tube on just needs tightened or
anything like that, it would more likely be that the seal
has dry rotted over time and needs replaced but I have no
idea if it is a part easily sourced or at a reasonable
price.

I do think it is time to retire this monitor.

 

[Strobe]

Greetings,

I do agree with you in general. The beast is going to be ten
in 6 months. Just hoping to defer the dollar outlay for a bit
... <s&g>.

Is there any risk that the steel band has become loose - hence
the infiltration - and that the case is actually
holding/reinforcing the tube? Not too excited about pulling
the front of the case off if this were to be the case.

Tim, be aware that there are TWO dangers when working with big CRTs.
There is, of course, the residual charge from the EHT, which can take hours to
drop to a safe level.

There is also the mechanical energy stored in the almost-perfect vacuum inside,
which is significant with large tubes.
There is nearly 15 pounds of pressure per square inch on the face of the tube.
A big CRT has a lot of square inches - do the math yourself!
IF the glass breaks, some bits of it could fly around.

Always be very careful when a big tube is out of its case.
When I need to work on the inside of a monitor, I rest it face down on the
cushion of an easy chair to avoid damage to the face plate when I remove
the case, because a scratch in the glass would weaken it and increase the
risk of an implosion.
If you must put it on a bench, always put some thick, smooth cushioning under
the glass.

I wouldn't even touch that tension band around the screen...

 

[Tim]

Tim, be aware that there are TWO dangers when working with
big CRTs. There is, of course, the residual charge from the
EHT, which can take hours to drop to a safe level.

There is also the mechanical energy stored in the
almost-perfect vacuum inside, which is significant with
large tubes. There is nearly 15 pounds of pressure per
square inch on the face of the tube. A big CRT has a lot of
square inches - do the math yourself! IF the glass breaks,
some bits of it could fly around.

Always be very careful when a big tube is out of its case.
When I need to work on the inside of a monitor, I rest it
face down on the cushion of an easy chair to avoid damage
to the face plate when I remove the case, because a scratch
in the glass would weaken it and increase the risk of an
implosion. If you must put it on a bench, always put some
thick, smooth cushioning under the glass.

I wouldn't even touch that tension band around the
screen...

Greetings,

Yeah ... <s&g> ... I've about convinced myself to pop for a
new monitor. What you've mentioned had well occurred to me.
Was just hoping someone had already tried a fix. ...

Now the question is: Has anyone any experience with AOC crt
displays?

 

[kony]

Greetings,

Yeah ... <s&g> ... I've about convinced myself to pop for a
new monitor. What you've mentioned had well occurred to me.
Was just hoping someone had already tried a fix. ...

Now the question is: Has anyone any experience with AOC crt
displays?

I would not buy a CRT monitor today (but maybe that's just
me, I find LCD the tech is what I had been waiting for, for
so long. I formerly always used Sony Trinitron or
Mitsubishi Diamondtron monitors for my last 3 (over a dozen
years prior to my first LCD)).

As for the tube being fragile, perhaps this is correct but I
never found it a problem. I try to be green (and cheap),
savenging and cannibalizing monitors for various parts
before I throw them (monitors) away and have not had any
problems removing the tension mounting band around the tube
(when present, other times it is not a band just rubber with
a steel clip in each corner) and don't see how one could
easily scratch a tube onto the point of breaking - but I had
the tube resting downward and had an alternate goal, not
reusing the whole monitor.

So basically I'm saying that in my opinion what you propose
can be done ok, given adequate caution, and depending on the
unknown aspect of a gasket material between tube and outer
viewing panel, but is very laborious and being considered
for a monitor already old enough that it's days are
numbered.

 

[Tim]

I would not buy a CRT monitor today (but maybe that's just
me, I find LCD the tech is what I had been waiting for, for
so long. I formerly always used Sony Trinitron or
Mitsubishi Diamondtron monitors for my last 3 (over a dozen
years prior to my first LCD)).

As for the tube being fragile, perhaps this is correct but I
never found it a problem. I try to be green (and cheap),
savenging and cannibalizing monitors for various parts
before I throw them (monitors) away and have not had any
problems removing the tension mounting band around the tube
(when present, other times it is not a band just rubber with
a steel clip in each corner) and don't see how one could
easily scratch a tube onto the point of breaking - but I had
the tube resting downward and had an alternate goal, not
reusing the whole monitor.

So basically I'm saying that in my opinion what you propose
can be done ok, given adequate caution, and depending on the
unknown aspect of a gasket material between tube and outer
viewing panel, but is very laborious and being considered
for a monitor already old enough that it's days are
numbered.

Greetings kony,

Thanks for the comments. I'm not considering discarding the
viewsonic. But, it's time is perhaps near the end.

I haven't researched this, but since you brought it up ... <s&g>
.... how do I evaluate lcds when comparing them to a crt? I run
the viewsonic (16in viewable) at 1152 x 864, 75 Hz refresh rate.
It has a .27mm dot pitch. This gives me adequate room for
overlapping windows, a good print size for me, and adequate
detail to do some graphics/photographic work. I plugged in a
15in lcd and found it's maximum/optimum resolution of 1024 x 768
to be thoroughly unacceptable on all counts, even after fiddling
with the various win xp desktop/scheme parameters.

I do have to research this as the viewsonic screen had a
distinctive green cast to it now.

Be well,

Tim

 

[kony]

I haven't researched this, but since you brought it up ... <s&g>
... how do I evaluate lcds when comparing them to a crt?

You dont' necessarily, instead buying what seems to fit your
present and future needs regardless of past use - because
applications and needs change over time.

I run
the viewsonic (16in viewable) at 1152 x 864, 75 Hz refresh rate.
It has a .27mm dot pitch. This gives me adequate room for
overlapping windows, a good print size for me, and adequate
detail to do some graphics/photographic work. I plugged in a
15in lcd and found it's maximum/optimum resolution of 1024 x 768
to be thoroughly unacceptable on all counts, even after fiddling
with the various win xp desktop/scheme parameters.

I do have to research this as the viewsonic screen had a
distinctive green cast to it now.

As for text, LCDs generally allow use of a little smaller
pixel pitch or further distance than a CRT would. I'd think
a 19" or 22" would be a starting point but only you can
decide of a widescreen monitor is what you want... they're
certainly more common today but there are still fair choices
in 19" 5:4 ratio in the market.

Graphics work may make a VA or IPS screen more suitable
because of better contrast and viewing angle. They cost a
bit more and are rarer in 22" size, you might go to some
stores and also look at the tradeoffs made with a 20.n"
screen as they're more often *VA or IPS instead of TN
panels. Budget has a lot to do with choices, after getting
an idea of the physical size and dot pitch you find
acceptible then online reviews can help in finding better
color and contrast among those size(s).

Something else worth considering is that you will probably
get used to whatever monitor you choose so long as it
doesn't have some particularly bad problem, will be able to
adapt and use it fine even if it doesn't look the same
side-by-side with what you were used to.

 

[Tim]

You dont' necessarily, instead buying what seems to fit
your present and future needs regardless of past use -
because applications and needs change over time.




As for text, LCDs generally allow use of a little smaller
pixel pitch or further distance than a CRT would. I'd
think a 19" or 22" would be a starting point but only you
can decide of a widescreen monitor is what you want...
they're certainly more common today but there are still
fair choices in 19" 5:4 ratio in the market.

Graphics work may make a VA or IPS screen more suitable
because of better contrast and viewing angle. They cost a
bit more and are rarer in 22" size, you might go to some
stores and also look at the tradeoffs made with a 20.n"
screen as they're more often *VA or IPS instead of TN
panels. Budget has a lot to do with choices, after getting
an idea of the physical size and dot pitch you find
acceptible then online reviews can help in finding better
color and contrast among those size(s).

Something else worth considering is that you will probably
get used to whatever monitor you choose so long as it
doesn't have some particularly bad problem, will be able to
adapt and use it fine even if it doesn't look the same
side-by-side with what you were used to.

Greetings,

Good points all. I will do some snooping, getting a better
understanding of the lcd vernacular. <g>

Had a power outage here. And I was outside working. So the
beast sat idle for nearly six hours. When I powered up the
system, the monitor power light was on but there was a black
screen. Turning the monitor power on and off brought it back
to life ... but with a distinctive green cast ... . After
being on for about 40 minutes the greenish-ness has faded
leaving the brownish gray. So I'd guess there's more the dust
on the tube! LOL! <g>

Thanks for the conversation. I'm probably 'off the air' for
awhile now for the rest of the day. Then, I'll go out and
look at all these 'new fangled' contraptions. <g>

Be well,

Tim

 

[larry moe 'n curly]

Yeah ... <s&g> ... I've about convinced myself to pop for a
new monitor. What you've mentioned had well occurred to me.
Was just hoping someone had already tried a fix. ...

Now the question is: Has anyone any experience with AOC crt
displays?

AOC is also sold as Envision, and my Envision EN-710 and EN-775 both
work fine after several years

If you need a new CRT monitor, try dumpsters or Craig's List because
lots of people are tossing them for LCDs, so the CRTs tend to be in
good condition. I've found them so plentiful that I no longer bother
with anything smaller than 19".

 

[larry moe 'n curly]

Is there any risk that the steel band has become loose - hence
the infiltration - and that the case is actually
holding/reinforcing the tube? Not too excited about pulling
the front of the case off if this were to be the case.

It's very unlikely that the steel band has loosened because it seems
to be welded together, and if it did loosen, I'm pretty sure that the
picture tube would fall inside and maybe implode/explode.

As far as I can see from this diagram for an AOC/Envision EN-775 or
EN-760 monitor, there's no separate outer flat cover for the screen:

http://farm3.static.flickr.com/2136/2193645267_64f5d9b08f_o.gif

 

[kony]

AOC is also sold as Envision, and my Envision EN-710 and EN-775 both
work fine after several years

What's an Envision EN-710 like? I was curious because I
have an Envision something-or-other 19" still, but looking
through one section of my rebate archives I only see a
listing for an EN-710e that I bought from Staples for $30
AR, but I can't remember it at all which must mean I had
bought it to be bundled with some system I sold, or that I'd
given it away to a relative.

The 19" Envision I still have is hardly impressive, it was
blurry compared to the Trinitron monitors I normally used a
the time and it's flat tube meant it had a curved tube
sitting behind a flat piece of glass - the difference
between it and a real flat tube was obvious, and yet I
didn't mind so much because it too had a large rebate
attached to the purchase price, plus it wasn't my primary
monitor.

If you need a new CRT monitor, try dumpsters or Craig's List because
lots of people are tossing them for LCDs, so the CRTs tend to be in
good condition. I've found them so plentiful that I no longer bother
with anything smaller than 19".

Speaking of which, I need to throw away a lot of old CRT
monitors, though most of them have dimmed over the years to
the point where they're hardly usable. IMO, a lot of people
aren't dumping monitors just to move to a CRT, they're doing
it because the monitor isn't very usable anymore. Maybe I
am only thinking of the DIY crowd, instead of those who buy
a new Dell that came with a bundled LCD for not so much
addt'l in price.

 

[kony]

It's very unlikely that the steel band has loosened because it seems
to be welded together, and if it did loosen, I'm pretty sure that the
picture tube would fall inside and maybe implode/explode.

As far as I can see from this diagram for an AOC/Envision EN-775 or
EN-760 monitor, there's no separate outer flat cover for the screen:

http://farm3.static.flickr.com/2136/2193645267_64f5d9b08f_o.gif

I agree the band wouldn't be loose, otherwise there would be
a clear gap between the outer glass and the plastic.

However my 19" Envision clearly does have an outer flat
glass panel that is not part of the CRT tube itself. I was
very disappointed when I first saw it was designed this way
yet advertised as a flat screen, but for the after-rebate
price plus the hassle of returning it, I accepted it for
secondary system use. I used it so seldom that today it
still works fine, eventually I'll replace it with an LCD
while it still works because I couldn't find anything
positive about it, and yet for the AR price it still serves
it's purpose well, affordably as just something to turn on
attached to a KVM for several systems in the basement.

For a short while I had a new 22" LCD I'd bought next to
it... there just isn't any comparison, that 19" Envision is
like living in the stone age and looking through glasses
with grease smeared on them.

Maybe I'm just biased, when I read of someone touting the
virtues of CRTs, and myself always using Trinitrons and even
then finding even the worst LCDs superior, I can't help but
think that faster response time and greater contrast mean
nothing if the pixels don't even show up as intended instead
of being blurred.

Granted, this is a VERY subjective thing, but I wish CRTs
had never existed, that we'd started out using LCDs and
they'd just advanced over the years.

 

[larry moe 'n curly]

On Mon, 14 Jan 2008 19:32:36 -0800 (PST), "larry moe 'n


What's an Envision EN-710 like? I was curious because I
have an Envision something-or-other 19" still, but looking
through one section of my rebate archives I only see a
listing for an EN-710e that I bought from Staples for $30
AR, but I can't remember it at all which must mean I had
bought it to be bundled with some system I sold, or that I'd
given it away to a relative.

Sorry, I meant EN-710e. Here's the service manual Envision e-mailed
me when I asked for the EN-710e manual:

http://rapidshare.com/files/84407134/D760T-SERVICE.doc.html

That service manual explains how to access the hidden adjustments,
like vertical linearity and color balance, and it also gives detailed
repair information, but for some reason the schematics were left out.

The 19" Envision I still have is hardly impressive, it was
blurry compared to the Trinitron monitors I normally used a
the time and it's flat tube meant it had a curved tube
sitting behind a flat piece of glass - the difference
between it and a real flat tube was obvious, and yet I
didn't mind so much because it too had a large rebate
attached to the purchase price, plus it wasn't my primary
monitor.

My EN-775 looks sharp, but my EN-710e was fuzzy at 1024x768 if the
refresh rate was above 60 Hz.

Speaking of which, I need to throw away a lot of old CRT
monitors, though most of them have dimmed over the years to
the point where they're hardly usable.

Even after the Screen control on the flyback or the sub-brightness
control was turned up?

IMO, a lot of people
aren't dumping monitors just to move to a CRT, they're doing
it because the monitor isn't very usable anymore. Maybe I
am only thinking of the DIY crowd, instead of those who buy
a new Dell that came with a bundled LCD for not so much
addt'l in price.

Out of around 15 monitors I've taken from the trash, most worked fine,
four I couldn't repair with my limited skills (or limited money), and
the rest needed only tweaking, resoldering, or some new capacitors.

 

[larry moe 'n curly]

For a short while I had a new 22" LCD I'd bought next to
it... there just isn't any comparison, that 19" Envision is
like living in the stone age and looking through glasses
with grease smeared on them.

Maybe I'm just biased, when I read of someone touting the
virtues of CRTs, and myself always using Trinitrons and even
then finding even the worst LCDs superior, I can't help but
think that faster response time and greater contrast mean
nothing if the pixels don't even show up as intended instead
of being blurred.

I guess that's the advantage of LCDs drawing their pixels practically
right at the screen instead of from a foot behind, as CRTs do. OTOH
some CRT monitors come from the factory with only so-so convergence at
the edges, and the focus there can be improved by tweaking the dynamic
adjustments and gluing additional magnets to the CRT or yoke.

 

[Rookie]

Now the question is: Has anyone any experience with AOC crt
displays?

They used to sell for cheap here. Some of the worse monitors I have ever
seen. The image was really blurry.