Prev: LCD Monitor problem - pixel over saturated in pictures where colors change
Next: Help identifying some crystals
From: David Nebenzahl on 27 Feb 2010 23:25
Well, I tried cleaning the dust out of my Dell-branded Trinitron tube.
In so doing I seem to have knocked the convergence out of whack, even
though I was really careful vacuuming around the CRT.

There's an on-screen convergence control, but even with it cranked all
the way over (to 100/100 for the horizontal control, 76 for the
vertical), there are still highly visible "ghosts" on screen.

Are there any other convergence controls I could adjust to get it
closer, like pots on one of the boards? Or how about trying to tweak the
deflection coils a tiny bit?

This monitor is on its last legs, so I'm not going to be investing a lot
(in terms of time, and $0 in money) in it. I'd just like to know if I
can get a few more weeks or months of use out of it.

Pity, really: when it worked well, this was an outstanding monitor.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
From: Michael Shell on 28 Feb 2010 00:48
On Sat, 27 Feb 2010 20:25:26 -0800
David Nebenzahl <nobody(a)but.us.chickens> wrote:

> Well, I tried cleaning the dust out of my Dell-branded Trinitron tube.
> In so doing I seem to have knocked the convergence out of whack, even
> though I was really careful vacuuming around the CRT.
>
> There's an on-screen convergence control, but even with it cranked all
> the way over (to 100/100 for the horizontal control, 76 for the
> vertical), there are still highly visible "ghosts" on screen.


Try demagnetizing it first, especially if your monitor has a built-in
degaussing button. The next step is to degauss with an external
demagnitizer. There are TV degaussing coils for this (check Ebay), but
you might be able to make do with something like a bulk tape eraser
if you already have one.

Color convergence problems will show up as red, blue or green outlines
and/or duplicate images - like when the colors don't align on newspaper
comic sections. If the ghosts you see are not in different colors,
then it is not a convergence problem. The focus control is often very
easy to unintentionally turn although a misadjusted focus control
generally causes blurriness rather than ghosts.


Cheers,

Mike Shell


From: David Nebenzahl on 28 Feb 2010 01:32
On 2/27/2010 9:48 PM Michael Shell spake thus:

> On Sat, 27 Feb 2010 20:25:26 -0800
> David Nebenzahl <nobody(a)but.us.chickens> wrote:
>
>> Well, I tried cleaning the dust out of my Dell-branded Trinitron tube.
>> In so doing I seem to have knocked the convergence out of whack, even
>> though I was really careful vacuuming around the CRT.
>>
>> There's an on-screen convergence control, but even with it cranked all
>> the way over (to 100/100 for the horizontal control, 76 for the
>> vertical), there are still highly visible "ghosts" on screen.
>
> Try demagnetizing it first, especially if your monitor has a built-in
> degaussing button. The next step is to degauss with an external
> demagnitizer. There are TV degaussing coils for this (check Ebay), but
> you might be able to make do with something like a bulk tape eraser
> if you already have one.

No bulk eraser, but I do have a couple of tape head demagnetizers;
wonder if they'd do any good. But the monitor has a built-in degausser
anyhow.

> Color convergence problems will show up as red, blue or green outlines
> and/or duplicate images - like when the colors don't align on newspaper
> comic sections. If the ghosts you see are not in different colors,
> then it is not a convergence problem. The focus control is often very
> easy to unintentionally turn although a misadjusted focus control
> generally causes blurriness rather than ghosts.

It's definitely a convergence problem. I can see the colors shifting
when I adjust the on-screen convergence control, but not far enough to
eliminate the ghosts (which are definitely in different colors). The
focus is fine.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
From: William Sommerwerck on 28 Feb 2010 06:41
> There's an on-screen convergence control, but even with it
> cranked all the way over (to 100/100 for the horizontal control,
> 76 for the vertical), there are still highly visible "ghosts" on screen.

My ViewSonic with a Diamondtron CRT also has two on-screen convergence
controls. However, I suspect they're for tweaking. There are almost
certianly other convergence controls within the monitor. You probably kocked
one loose (so to speak) during cleaing.


From: Mark Zacharias on 28 Feb 2010 08:55
"David Nebenzahl" <nobody(a)but.us.chickens> wrote in message
news:4b8a0cd8$0$2363$822641b3(a)news.adtechcomputers.com...
> On 2/27/2010 9:48 PM Michael Shell spake thus:
>
>> On Sat, 27 Feb 2010 20:25:26 -0800
>> David Nebenzahl <nobody(a)but.us.chickens> wrote:
>>
>>> Well, I tried cleaning the dust out of my Dell-branded Trinitron tube.
>>> In so doing I seem to have knocked the convergence out of whack, even
>>> though I was really careful vacuuming around the CRT.
>>>
>>> There's an on-screen convergence control, but even with it cranked all
>>> the way over (to 100/100 for the horizontal control, 76 for the
>>> vertical), there are still highly visible "ghosts" on screen.
>>
>> Try demagnetizing it first, especially if your monitor has a built-in
>> degaussing button. The next step is to degauss with an external
>> demagnitizer. There are TV degaussing coils for this (check Ebay), but
>> you might be able to make do with something like a bulk tape eraser
>> if you already have one.
>
> No bulk eraser, but I do have a couple of tape head demagnetizers; wonder
> if they'd do any good. But the monitor has a built-in degausser anyhow.
>
>> Color convergence problems will show up as red, blue or green outlines
>> and/or duplicate images - like when the colors don't align on newspaper
>> comic sections. If the ghosts you see are not in different colors,
>> then it is not a convergence problem. The focus control is often very
>> easy to unintentionally turn although a misadjusted focus control
>> generally causes blurriness rather than ghosts.
>
> It's definitely a convergence problem. I can see the colors shifting when
> I adjust the on-screen convergence control, but not far enough to
> eliminate the ghosts (which are definitely in different colors). The focus
> is fine.
>
>
> --
> You were wrong, and I'm man enough to admit it.
>
> - a Usenet "apology"


If it does relate to degaussing, the built-in coil, while not strong enough
to fix it on one or two tries, might get the job done over the course of
time, which is to say, a certain number of degauss cycles. Sony CRT's can be
damaged by conventional hand held coils, though in practice I've not seen
this happen. I think that particular caution only applied to their larger
CRT's.

Mark Z.

 |  Next  |  Last
Pages: 1 2 3
Prev: LCD Monitor problem - pixel over saturated in pictures where colors change
Next: Help identifying some crystals