My 17 inch CRT sometimes gets ...

light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

This d*mn lead seems quite sensitive because slight kinks and bends
in the lead can create this effect. So can gently moving the plug as
it goes into the video card. Why can't they design a better lead
than this? It is already the most inflexible lead on my whole
system!

MY QUESTION IS ... is this lead usually as sensitive as this or is it
related to the design of my particular monitor and PC interface.

Can I do anything to improve the situation? I have lowered the
screen refresh rate a bit but that doesn't seem to have help.

Is there a "magic bullet" like something to clip onto the leqad or
some screening.

Changing the lead means some tricky messing around inside the monitor
to terminate the leads it in the screened cage sitting on the cathode
parts of the CRT itself.

Any ideas?

Jon


[Please don't say buy a secondhand 17inch monitor for next to nothing
because cleaning it and dusting out its internals to sharpen up the
image and all that stuff takes time, and so does fetching a checking
over monitors which turn out to be crap.]

Jon D wrote:

My 17 inch CRT sometimes gets ...

light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

They can fail.

This d*mn lead seems quite sensitive because slight
kinks and bends in the lead can create this effect.

You only get that if its got a break in the wire or at the connector.

So can gently moving the plug as it goes into the video card.

Likely thats where the problem is.

Why can't they design a better lead than this?

They can, you dont see that with most CRTs.

It is already the most inflexible lead on my whole system!

Because its got the most wires in it.

MY QUESTION IS ... is this lead usually as sensitive as this

Nope, most CRTs dont behave like that.

or is it related to the design of my particular monitor and PC interface.

Not the design, the actual implementation of the cable/connector.

Can I do anything to improve the situation?

Yes, replace the cable and connector if you dont get that
effect with a different CRT. If you do, its the video card.

I have lowered the screen refresh rate
a bit but that doesn't seem to have help.

Yeah, wont make any difference.

Is there a "magic bullet" like something to
clip onto the leqad or some screening.

The problem is a physical break in the cable/connector.

Changing the lead means some tricky messing around
inside the monitor to terminate the leads it in the screened
cage sitting on the cathode parts of the CRT itself.

Yeah, tho you can find that the break is actually in
the connector itself, or even just a broken pin there.

Any ideas?

Replace it with a 19" CRT.

[Please don't say buy a secondhand 17inch monitor for next
to nothing because cleaning it and dusting out its internals to
sharpen up the image and all that stuff takes time, and so does
fetching a checking over monitors which turn out to be crap.]

Then buy a new one.

[Please don't say buy a secondhand 17inch monitor for next
to nothing because cleaning it and dusting out its internals to
sharpen up the image and all that stuff takes time, and so does
fetching a checking over monitors which turn out to be crap.]

Then buy a new one.

Or don't do anything at all..

You probably have corroded solder connections
where that pc board hooks to the input cable.
Very common in old crts. Sounds like you also
have a flyback going bad. Time for new monitor.

johns

johns ha escrito:

You probably have corroded solder connections
where that pc board hooks to the input cable.
Very common in old crts. Sounds like you also
have a flyback going bad. Time for new monitor.

johns

Please explain how a bad flyback can cause the fault described by the
original poster.

Please explain how a bad flyback can cause the fault described by the
original poster.

Picture size .. blooming .. is caused by high
voltage changing. Generally when the solder
joints start going, it occurs across all the power
handling connections, and at the flyback. Also,
the electrolytics tend to crap out and lose their
capacitance .. even to dead shorts. I've been
into lots of crts where all I did was touch up
solder connections and replace electrolytics
.... and the thing ran fine. Of course that did not
fix the gassy crt which starts the picture to
blur. TRUTH: I've had people come in and say
"just make it work. I'll pay the cost. I like my
crt". So, I clean it ... resolder a bunch of
points .. replace horizontal output transistor
.... replace flyback ... run tube through phosphor
restore and degauss ... set flyback focus ..
dark level ... remove and test all the big
electrolytics, and replace a bunch of them
.... replace the the transistor amps and current
limit resistors on the crt board ... put it back
together and clean the case and screen to
nearly new ... and charge the lady 3 hours
labor at $65 per hour plus parts .. and hope
to heaven that the 90 day warranty holds :-)

johns

Jon D wrote:

My 17 inch CRT sometimes gets ...

light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

This d*mn lead seems quite sensitive because slight kinks and bends
in the lead can create this effect. So can gently moving the plug as
it goes into the video card. Why can't they design a better lead
than this? It is already the most inflexible lead on my whole
system!

MY QUESTION IS ... is this lead usually as sensitive as this or is it
related to the design of my particular monitor and PC interface.

Can I do anything to improve the situation? I have lowered the
screen refresh rate a bit but that doesn't seem to have help.

Is there a "magic bullet" like something to clip onto the leqad or
some screening.

Changing the lead means some tricky messing around inside the monitor
to terminate the leads it in the screened cage sitting on the cathode
parts of the CRT itself.

Any ideas?

Jon

Sounds like a flyback problem, but it might just be a poor connection
on the sync pulse line. Prodding should lead you to see where its most
sensitive, and thus where the probelm is. Typically its cable ends or
connectors.

The good news is this fault is likely non-fatal. Having retrace lines
scattered over the screen doesnt exactly make it look better, but it
means you can wait to see if it goes bad, and if it does find a monitor
then.


NT

johns wrote:

Please explain how a bad flyback can cause
the fault described by the original poster.

Picture size .. blooming .. is caused by high voltage changing.

Yes, but you havent established that the real reason
for the picture size changing is because the monitor
is getting confused by the obvious glitches on the
cable into changing the screen mode etc.

Generally when the solder joints start going,
it occurs across all the power handling connections,

Oh bull****. You only get bad joints where large components are
soldered onto the pcb and they start to fail due to thermal cycling.

and at the flyback.

Utterly mangled all over again. Flybacks fail quite differently.

Also, the electrolytics tend to crap out and
lose their capacitance .. even to dead shorts.

No evidence of that in the symptoms the OP mentioned.

I've been into lots of crts where all I did was
touch up solder connections and replace
electrolytics ... and the thing ran fine.

Sure, but that doesnt appear to be the OP's problem
given that its so sensitive to the video cable.

Of course that did not fix the gassy
crt which starts the picture to blur.

TRUTH: I've had people come in and say
"just make it work. I'll pay the cost. I like my
crt". So, I clean it ... resolder a bunch of
points .. replace horizontal output transistor
... replace flyback ... run tube through phosphor
restore and degauss ... set flyback focus ..
dark level ... remove and test all the big
electrolytics, and replace a bunch of them
... replace the the transistor amps and current
limit resistors on the crt board ... put it back
together and clean the case and screen to
nearly new ... and charge the lady 3 hours
labor at $65 per hour plus parts .. and hope
to heaven that the 90 day warranty holds :-)

Irrelevant to what the OP's symptoms indicate.

wrote:
Jon D wrote:

My 17 inch CRT sometimes gets ...

light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

This d*mn lead seems quite sensitive because slight kinks and bends
in the lead can create this effect. So can gently moving the plug as
it goes into the video card. Why can't they design a better lead
than this? It is already the most inflexible lead on my whole
system!

MY QUESTION IS ... is this lead usually as sensitive as this or is it
related to the design of my particular monitor and PC interface.

Can I do anything to improve the situation? I have lowered the
screen refresh rate a bit but that doesn't seem to have help.

Is there a "magic bullet" like something to clip onto the leqad or
some screening.

Changing the lead means some tricky messing around inside the monitor
to terminate the leads it in the screened cage sitting on the cathode
parts of the CRT itself.

Any ideas?

Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.

but it might just be a poor connection on the sync pulse line.
Prodding should lead you to see where its most sensitive, and
thus where the probelm is. Typically its cable ends or connectors.

The good news is this fault is likely non-fatal. Having retrace lines
scattered over the screen doesnt exactly make it look better, but it
means you can wait to see if it goes bad, and if it does find a monitor then.

Rod Speed ha escrito:



Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.


That´s exactly what I thought. A bad flyback will not worsen or
improve by "wiggling" the VGA cable of the monitor. In other words, if
the fault dissapears by wiggling the VGA cable, that rules out the
flyback and other components of the monitor.

johns ha escrito:

Please explain how a bad flyback can cause the fault described by the
original poster.

Picture size .. blooming .. is caused by high
voltage changing.

True, but high voltage changes can be caused by a number of other
things, not just the flyback.

Generally when the solder
joints start going, it occurs across all the power
handling connections, and at the flyback.

OK, but that can be solved by simply resoldering the faulty joints. No
need to blame the flyback on that, or to replace it blindly.

Also,
the electrolytics tend to crap out and lose their
capacitance .. even to dead shorts.

Bad electrolytics in the PSU can be the origin of the high voltage
changes.

I've been
into lots of crts where all I did was touch up
solder connections and replace electrolytics
... and the thing ran fine. Of course that did not
fix the gassy crt which starts the picture to
blur. TRUTH: I've had people come in and say
"just make it work. I'll pay the cost. I like my
crt". So, I clean it ... resolder a bunch of
points .. replace horizontal output transistor
... replace flyback ... run tube through phosphor
restore and degauss ... set flyback focus ..
dark level ... remove and test all the big
electrolytics, and replace a bunch of them
... replace the the transistor amps and current
limit resistors on the crt board ...

I don´t understand why do you replace the CRT drivers and the HOT if
they are OK. I can understand that part about replacing aged
electrolytics, redoing any stressed solder joints and restoring the
CRT... but why to replace transistors if they are ok?

Jon D wrote:
My 17 inch CRT sometimes gets ...
light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

This d*mn lead seems quite sensitive because slight kinks and bends
in the lead can create this effect.

I've never seen light-colored lines like that caused by a bad monitor
cable, which usually causes the color to be funny all over the screen
or change abruptly.

Please don't say buy a secondhand 17inch monitor for next to nothing

Buy? They're free.

because cleaning it and dusting out its internals to sharpen up the
image and all that stuff takes time,

How long can cleaning take? Almost every one I've found was very
clean.

How does cleaning the inside make the image sharper? There are 1-2
focus adjustments inside, but it takes just seconds to adjust each one.

lsmartino wrote:
Rod Speed ha escrito:

Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.

That´s exactly what I thought. A bad flyback will not worsen or
improve by "wiggling" the VGA cable of the monitor. In other words,
if the fault dissapears by wiggling the VGA cable, that rules out
the flyback and other components of the monitor.

Wiggling the flyback can disturb the horizontal sync, which in turn
disturbs the HV, which in turn affects the picture size.

--
Chuck F ) )
Available for consulting/temporary embedded and systems.
http://cbfalconer.home.att.net USE maineline address!

because cleaning it and dusting out its internals to sharpen up the
image and all that stuff takes time,

The admission by the OP of being a troll, in plain sight, and nobody
noticed!

wrote:

because cleaning it and dusting out its internals to
sharpen up the image and all that stuff takes time,

The admission by the OP of being a troll, in plain sight, and nobody noticed!

Nothing to notice except you jumping at bogeymen.

Rod Speed wrote:
wrote:
Jon D wrote:

I have tracked this down to the signal lead going from PC to monitor.

Any ideas?

Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.

sorry, I though it was obvious. Wiggling a thick fat cable will wiggle
the main pcb slightly, which may disturb any poor connection anywhere
on the board.


NT

wrote
Rod Speed wrote
wrote
Jon D wrote

I have tracked this down to the signal lead going from PC to monitor.

Any ideas?

Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.

sorry, I though it was obvious.

Never ever could bull**** its way out of a wet paper bag.

Wiggling a thick fat cable will wiggle the main pcb slightly,

Not if you only fiddle with the video card end it doesnt.

which may disturb any poor connection anywhere on the board.

Pity the FBT isnt even on that board.

I don´t understand why do you replace the CRT drivers and the HOT if
they are OK. I can understand that part about replacing aged
electrolytics, redoing any stressed solder joints and restoring the
CRT... but why to replace transistors if they are ok?

Because you are in there. It takes bench time $$$$ just to
open the thing, and so you don't take chances on the HOT,
flyback, power electrolytics, CRT board adjustments .. esp
the driver transistors and current limit resistors. All of those
points "heat cycle" badly, and the solder joints crack. That
causes any movement of the video cable to wiggle those
bad joints and glitch the picture in a million ways. A bench
tech can't spend time diagnosing that stuff. I just shotgun
all the potentially weak areas and run a bench test for about
an hour to watch the video cycle. If it works ... start praying
for 90 days. Otherwise .. MAD BOSS ... mad mad Boss !
Something else .. all those parts run about $30 total on the
bill. Stupid not to replace them. More stupid is to repair the
thing at all, but that is not my option, and some customers
simply believe in maintaining their hardware.

johns

Wiggling the cable wiggles the entire monitor.
What drives me crazy is to pick up the monitor
and carry it back to the test bench, and have it
run perfectly :-)

johns

johns ha escrito:


Because you are in there. It takes bench time $$$$ just to
open the thing, and so you don't take chances on the HOT,
flyback, power electrolytics, CRT board adjustments .. esp
the driver transistors and current limit resistors. All of those
points "heat cycle" badly, and the solder joints crack.

Just resoldering the transistors will suffice. No need to replace them
blindly.


That
causes any movement of the video cable to wiggle those
bad joints and glitch the picture in a million ways. A bench
tech can't spend time diagnosing that stuff. I just shotgun
all the potentially weak areas and run a bench test for about
an hour to watch the video cycle. If it works ... start praying
for 90 days. Otherwise .. MAD BOSS ... mad mad Boss !
Something else .. all those parts run about $30 total on the
bill. Stupid not to replace them. More stupid is to repair the
thing at all, but that is not my option, and some customers
simply believe in maintaining their hardware.


I agree, trying to repair a computer monitor from 1994 is a waste of
money.

CBFalconer ha escrito:

lsmartino wrote:
That´s exactly what I thought. A bad flyback will not worsen or
improve by "wiggling" the VGA cable of the monitor. In other words,
if the fault dissapears by wiggling the VGA cable, that rules out
the flyback and other components of the monitor.

Wiggling the flyback can disturb the horizontal sync, which in turn
disturbs the HV, which in turn affects the picture size.

--
Chuck F ) )
Available for consulting/temporary embedded and systems.
http://cbfalconer.home.att.net USE maineline address!

Please, reread the post. I said "...A bad flyback will not worsen or
improve by "wiggling" the VGA CABLE OF THE MONITOR..." Did you noticed
the "VGA CABLE" part of the sentence?

And the Flyback isn´t even in the same PCB as the VGA cable is. So
there is no way that disturbing the VGA cable will cause any physical
displacement of the flyback.

johns wrote:

Wiggling the cable wiggles the entire monitor.

Wrong again, particularly when you deliberately
restrain the cable and wiggle/flex the video card end.

What drives me crazy is to pick up the monitor and carry
it back to the test bench, and have it run perfectly :-)

That pulls the wire .. which pulls the other end connector
.... which pulls the crt card .. which wiggles the crt ..
which wiggles the main board ... you can't test that
way. It will fool you a million times.

johns

johns wrote
Rod Speed wrote
johns wrote

Wiggling the cable wiggles the entire monitor.

Wrong again, particularly when you deliberately
restrain the cable and wiggle/flex the video card end.

That pulls the wire ..

No it doesnt if you restrain the cable.

which pulls the other end connector

No it doesnt if you restrain the cable.

... which pulls the crt card ..

No it doesnt if you restrain the cable.

which wiggles the crt ..

No it doesnt if you restrain the cable.

which wiggles the main board ...

No it doesnt if you restrain the cable.

you can't test that way.

Corse you can.

It will fool you a million times.

Only those that are very easily fooled and cant
even manage to restrain the cable while flexing
the video card end.

Only those that are very easily fooled and cant
even manage to restrain the cable while flexing
the video card end.


Agreed... Sounds like a bad VGA cable or possibly the connector on the
video card. I don't even know why there is even any debate about this.
Replace the VGA cable first. If the problem still exsists afterwards it is
elsewhere. The guy talking about the flyback is just trying to be a troll
and start a huge arguement over nothing.

Rod Speed wrote:
wrote:

because cleaning it and dusting out its internals to
sharpen up the image and all that stuff takes time,

The admission by the OP of being a troll, in plain sight, and nobody noticed!

Nothing to notice except you jumping at bogeymen.

The following extracted from:-

http://en.wikipedia.org/wiki/Interne...seeking_trolls

Attention-seeking trolls

This class of trolls seeks to incite as many responses as possible and
to absorb a disproportionate share of the collective attention span.

* Messages containing a deliberate flaw or error: "I think 2001: A
Space Odyssey is Roman Polanski's best film." Or "Federico Fellini is
the Greatest Living American Director"

*Asking for help with an implausible task or problem: "How do I season
my Crock Pot? I don't want everything I cook in it to taste the same."

*Intentionally naive questions: "Can I cook pasta in Evian instead of
water?"

*Intentionally posting an outrageous argument, deliberately constructed
around a fundamental but obfuscated flaw or error. Often the poster
will become defensive when the argument is refuted, and may continue
the thread through the use of further flawed arguments; this is
referred to as "feeding" the troll.

Rod Speed wrote:

Never ever could bull**** its way out of a wet paper bag.
Pity the FBT isnt even on that board.

If you dont think wiggling a thick fat video cable can wiggle the
plastic base that the main board sits on, and thus the main board, then
either you havent repaired too many monitors, or youre a moron. Almost
certainly both.

NT

wrote
Rod Speed wrote
wrote
Rod Speed wrote
wrote
Jon D wrote

I have tracked this down to the signal lead going from PC to monitor.

Any ideas?

Sounds like a flyback problem,

Nope, doesnt explain the sensitivity to the video cable.

sorry, I though it was obvious.

Never ever could bull**** its way out of a wet paper bag.

Wiggling a thick fat cable will wiggle the main pcb slightly,

Not if you only fiddle with the video card end it doesnt.

which may disturb any poor connection anywhere on the board.

Pity the FBT isnt even on that board.

If you dont think wiggling a thick fat video cable can wiggle the
plastic base that the main board sits on, and thus the main board,

Never ever could bull**** its way out of a wet paper bag.

then either you havent repaired too many monitors,
or youre a moron. Almost certainly both.

Any 2 year old could leave that for dead.

Get one to help you before posting again, if anyone is
actually stupid enough to let you anywhere near one.

wrote
Rod Speed wrote
wrote

because cleaning it and dusting out its internals to
sharpen up the image and all that stuff takes time,

The admission by the OP of being a troll, in plain sight, and
nobody noticed!

Nothing to notice except you jumping at bogeymen.

The following extracted from:-

http://en.wikipedia.org/wiki/Interne...seeking_trolls

Attention-seeking trolls

This class of trolls seeks to incite as many responses as possible and
to absorb a disproportionate share of the collective attention span.

* Messages containing a deliberate flaw or error: "I think 2001: A
Space Odyssey is Roman Polanski's best film." Or "Federico Fellini is
the Greatest Living American Director"

*Asking for help with an implausible task or problem: "How do I season
my Crock Pot? I don't want everything I cook in it to taste the same."

*Intentionally naive questions: "Can I cook pasta in Evian instead of
water?"

*Intentionally posting an outrageous argument, deliberately
constructed around a fundamental but obfuscated flaw or error. Often
the poster will become defensive when the argument is refuted, and
may continue the thread through the use of further flawed arguments;
this is referred to as "feeding" the troll.

All completely irrelevant to whether what he was doing
had anything what so ever to do with attention seeking.

He may well be just another rather irrational individual.

On 26 Aug 2006 06:24:41 -0700, wrote:

Rod Speed wrote:

Never ever could bull**** its way out of a wet paper bag.
Pity the FBT isnt even on that board.

If you dont think wiggling a thick fat video cable can wiggle the
plastic base that the main board sits on, and thus the main board, then
either you havent repaired too many monitors, or youre a moron. Almost
certainly both.

NT


It depends entirely on how well that cable is fixed
internally. Some certainly would but quite a few wouldn't.
So yes it's possible but not necessary true.

Hi Jon

As electronic equipment gets older, the Electrolytics begin to fail, the ESR
begins to rise.
A failing Electrolytic would cause top fold over.
If you look at a typical vertical drive circuit, Electrolytics near the
circuit B+ to ground would cause top fold over,
While Electrolytics near ground potential to ground would cause bottom
linearity problems.



Jon D wrote in message
...
My 17 inch CRT sometimes gets ...

light-colored horizontal lines
a couple of inches above the bottom of the screen
usually just one or two of these
the picture size too *sometimes* seems to get a tiny bit smaller
when these lines are present.

I have tracked this down to the signal lead going from PC to monitor.

This d*mn lead seems quite sensitive because slight kinks and bends
in the lead can create this effect. So can gently moving the plug as
it goes into the video card. Why can't they design a better lead
than this? It is already the most inflexible lead on my whole
system!

MY QUESTION IS ... is this lead usually as sensitive as this or is it
related to the design of my particular monitor and PC interface.

Can I do anything to improve the situation? I have lowered the
screen refresh rate a bit but that doesn't seem to have help.

Is there a "magic bullet" like something to clip onto the leqad or
some screening.

Changing the lead means some tricky messing around inside the monitor
to terminate the leads it in the screened cage sitting on the cathode
parts of the CRT itself.

Any ideas?

Jon


[Please don't say buy a secondhand 17inch monitor for next to nothing
because cleaning it and dusting out its internals to sharpen up the
image and all that stuff takes time, and so does fetching a checking
over monitors which turn out to be crap.]

Eric wrote:

Hi Jon

As electronic equipment gets older, the Electrolytics begin to fail, the ESR
begins to rise.
A failing Electrolytic would cause top fold over.
If you look at a typical vertical drive circuit, Electrolytics near the
circuit B+ to ground would cause top fold over,
While Electrolytics near ground potential to ground would cause bottom
linearity problems.

a novel explanation.

Lytics are always suspects, but I wouldnt give them too hard a time.
All but one of the lytics on my 1930s radio are still fine.


NT

wrote in message
oups.com...
Eric wrote:

Hi Jon

As electronic equipment gets older, the Electrolytics begin to fail, the
ESR
begins to rise.
A failing Electrolytic would cause top fold over.
If you look at a typical vertical drive circuit, Electrolytics near the
circuit B+ to ground would cause top fold over,
While Electrolytics near ground potential to ground would cause bottom
linearity problems.

a novel explanation.

Lytics are always suspects, but I wouldnt give them too hard a time.
All but one of the lytics on my 1930s radio are still fine.


NT
That may be true, but today's lytics are driven pretty hard, especially in
switchers and vert output sections. It's also based on the quality of the
lytic.
My bench service on home entertainment goods shows an awful lot of dried up
lytics, and bad solder joints. With rohs, I suspect the latter will become
even more problematic.
regards,
tom

On Tue, 05 Sep 2006 13:54:42 +0100, Jon D
wrote:


I am the OP.

Guess you haven't read this thread earlier this year in
sci.electronics.components

http://tinyurl.com/jftyr
"Any value in cleaning inside old monitor?"

Many were skeptical like you. But the most convincing answers came from
those who knew there was a value in doing this and I think they were the
majority.

Nope, they did what most do, made random theories about what
hypothetical advantage there might be, without any real
evidence to support the theories. Let's suppose it did help
a particular monitor, is that then evidence it is going to
help most of them? No.

Further we'd first need to know how old the monitor is (is
it even worthwhile), how much crud accumulation there was,
and a measured deviation from appropriate operational
values. Of course it's not good to let parts overheat, or
conduct along unintended paths... but what remains is
actually having that happen. A monitor so poorly designed
that it can't stand a little bit of dust may not be worth
the effort, and one buried in dust might only be a sign of
the real problem- the room needs better air cleaning
equipment, instead of individually cleaning out every part
over and over again.





EXTRACTS ...

keeping components hotter than they would be if running in
"free air" conditions.

Not only does it have the chance of getting onto circuitry, it also
changes the capacitance of the tube wall, changing the circuit for the
CRT drive elements as well.


The collection of dust, and much of that moistened at
some point makes for a leaky anode supply and feed wire at the very
least. That makes for poor or shifted focus settings, and other
problems that less than your average video afficianado won't notice.

Most folks rarely notice their focus shifting as well. One has to be
video oriented to notice such things.

Just to back the pro cleaning side, when I made my living from servicing
monitors (and before that TVs) every once in a while I'd get one on the
bench with the safety shutdown tripping because of a buildup of crap
around the anode connector or other HV parts, but then I've also had
nearly as many repairs in that people had damaged cleaning the inside
when they didn't know what they were doing!


What good does it do to only provide "extracts" that support
your biased opinion? Here's one you left out:

On 3 Apr 2006, Sam Goldwasser wrote:

If you're obsessive-compulsive and have nothing better to
do, by all
means clean the insides of your CRT equipment. But it's
probably more
likely that something will get messed accidentally, than any
significant
improvement in either performance or life span.


The high voltage area of modern CRT equipment is generally
enclosed and
or sealed with HV grease or adhesive. It's not like old
all-tube-type
TVs where everything collected an inch of dust if you turned
your back.


Yes, dust does collect. And yes in principle that may
affect something
eventually. But if there are no symptoms, leave it alone.

On 05 Sep 2006, kony wrote:

On Tue, 05 Sep 2006 13:54:42 +0100, Jon D
wrote:


I am the OP.

Guess you haven't read this thread earlier this year in
sci.electronics.components

http://tinyurl.com/jftyr
"Any value in cleaning inside old monitor?"

Many were skeptical like you. But the most convincing answers came
from those who knew there was a value in doing this and I think
they were the majority.

Nope, they did what most do, made random theories about what
hypothetical advantage there might be, without any real
evidence to support the theories. Let's suppose it did help
a particular monitor, is that then evidence it is going to
help most of them? No.

Further we'd first need to know how old the monitor is (is
it even worthwhile), how much crud accumulation there was,
and a measured deviation from appropriate operational
values. Of course it's not good to let parts overheat, or
conduct along unintended paths... but what remains is
actually having that happen. A monitor so poorly designed
that it can't stand a little bit of dust may not be worth
the effort, and one buried in dust might only be a sign of
the real problem- the room needs better air cleaning
equipment, instead of individually cleaning out every part
over and over again.



I did what that thread suggested and I got a pleasant surprise in the
improved focus.

Maybe my monitor is ****e.

Maybe my room is ****e.

But that's my monitor and that's my room. And that what I have to
deal with. A good de-dusting works nicely.



EXTRACTS ...

keeping components hotter than they would be if running in
"free air" conditions.

Not only does it have the chance of getting onto circuitry, it also
changes the capacitance of the tube wall, changing the circuit for
the CRT drive elements as well.


The collection of dust, and much of that moistened at
some point makes for a leaky anode supply and feed wire at the very
least. That makes for poor or shifted focus settings, and other
problems that less than your average video afficianado won't
notice.

Most folks rarely notice their focus shifting as well. One has to
be video oriented to notice such things.

Just to back the pro cleaning side, when I made my living from
servicing monitors (and before that TVs) every once in a while I'd
get one on the bench with the safety shutdown tripping because of a
buildup of crap around the anode connector or other HV parts, but
then I've also had nearly as many repairs in that people had
damaged cleaning the inside when they didn't know what they were
doing!


What good does it do to only provide "extracts" that support
your biased opinion? Here's one you left out:


I am glad to see you went to the thread and look through it. Well
done.

OTOH my extracts were for those folks who are sort of 50:50 undecided
about checking that thread out. So I posted a random selection of
extracts to show its relevance in the hope that the 50:50 readers
would go and look.

Hey! I did write, "Many were skeptical".



On 3 Apr 2006, Sam Goldwasser wrote:

If you're obsessive-compulsive and have nothing better to do, by
all means clean the insides of your CRT equipment. But it's
probably more likely that something will get messed accidentally,
than any significant improvement in either performance or life
span.

The high voltage area of modern CRT equipment is generally enclosed
and or sealed with HV grease or adhesive. It's not like old
all-tube-type TVs where everything collected an inch of dust if you
turned your back.

Yes, dust does collect. And yes in principle that may
affect something eventually. But if there are no symptoms, leave
it alone.