"Meat Plow" wrote in message
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On Tue, 3 Nov 2009 11:20:52 -0000, "Colin Trunt"
wrote:


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On Mon, 2 Nov 2009 15:14:22 -0000, "Colin Trunt"
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On Mon, 2 Nov 2009 11:45:48 -0000, "Colin Trunt"
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On Fri, 30 Oct 2009 01:16:44 -0000, "Colin Trunt"
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On Thu, 29 Oct 2009 17:38:55 -0000, "Colin Trunt"
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On Wed, 28 Oct 2009 21:23:13 -0000, "Colin Trunt"
wrote:


"Meat Plow" wrote in message
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On Wed, 28 Oct 2009 12:39:07 -0000, "Colin Trunt"
wrote:

OK so it was hissing, I see blue arcing on the tube on the
cap,
is also covered in tobacco smoke/dirt. I tried some insulating
tape
at first, which worked for a while but not the next day.
Anyway I cleaned up around the cap a bit untill I did not get
much
arcing
or any arching.
Anyway now when I switch on the picture is blurred, however it
gets
better
and after about 15 minutes it is back to normal or very near
to.

So how do I make it work from cold, ie no blurred picture.
There was also some hissing this morning and some faint
arching
but that seemed to clear up afer a few minutes.

I am thinking cleaning a larger area would help.

I am not sure why the picture eventually sorts it self out
slowly
after switching on.

Is something heating up?


How was the focus when it was hissing? Often the focus
reference
is
part of the anode voltage circuit and could be strained by the
additional current when arcing.


Well generally bad, but when it first started hissing I think it
was
OK
it was just the noise which was annoying.
Only after my various attempts at cleaning where the arcing was
coming
from
did the out of focus stuff start appearing.
There may still have been some arching then but less visable and
more
silent.
What tends to happen is the picture slowly 'unblurs' itself, and
the
hissing
if any goes
away.
I was king of thinking that cleaning an area disturbed the
electrical
charastics of the
tube, unbalancing it, I though maybe if I cleaned all of the
tube
it
might
restore
that balance as it would have an even spread of surface
charastics.
However eventually it does restore focus fully even with an
unevenly
cleaned
tube.

I am thinking maybe the surface 'dries out' or the surface
charges
up
to
restore an
even 'balance'.
It is when it has been switch on after a long period off that it
is
blurred.
If I switch it on an off now it remains unblurred because it has
'warmed
up'.


Incidently I have just started using an old cumputer monitor as
a
second
terminal
and I can hear it hissing!! High humitity is part of the problem
I
think.
The picture looks OK maybe a little blured hard to say, it's not
very
bright
though.


I guess the only action I can take is to clean it throughly. I
mean
I
have
no parts
or a soldering iron etc... so thats about all I can do anyway.

I wil try giving it a good clean when I have the time.

Thanks for your input.


Watch the anode hole on the CRT, it will store high voltage and
will
shock you. Running a bead of silicone rubber around the outside
of
the
cap on the CRT surface can stop arcs if the surface of the CRT
is
carbon etched from arcing.


Not sure if I have any silicone rubber or not, or indeed what it
is
:O)
I might have some plumbers white silicon stuff though.

I was wondering about the cap, as I had lifted it up, I was
wondering
if I meeded to clean under it.

I saw the wires that go to the anode and I thought maybe I had
disturbed
the
position of the anode, but obviously not as that would not
selfright
itself.

The area I didn't clean look black but the clean are alooks pretty
OK.

It's not a mojor problem though, I normally switch it on beforeI
want
to
watch it so by the time I do the picture is perfectly fine.

I was thinking of getting one of those new fangled flat screen
ones too. I could also do with a flatscreen as a second monitor.
When I used the old one I was reminded of how small the screen
is and how big and heavy the monitor itself actually is!!



If your white silicone is 100% silicone that would work too. But
if
it
isn't arcing it doesn't need more cleaning or silicone. The damage
is
done and you probably need a focus divider or whatever on your
particular set provides the focus grid inside the CRT with
voltage.

I think when it I first switch it on it may be arcing and hissing a
little,
it was not like the arcing which I had before I cleaned it (or
cleaned
a smaller area) where you could see a fairly distinctive arc, but
rather more of a sort of 'glow' over the top of part of the tube.
There was an area which was sort of 'illuminated).

Actualy it may have been several 'mini-arcs' certainlty the curve of
the tube would make a straight one impossible, maybe if I clean it
better,
it will help.

Hmmm cleaned it a lot more but it's hard to get at a lot of it.
Still blurred when I switched on, then after a while the picture
started narrowing (going widescreen so to speak!!).
What would cause that?
Anyway I switched it off again and had another go at drying it, put
it back on and it was back to full screen and not as blured, it was
soon back to unblurred, but it had had a bit of a 'warm up' from
earlier.

Picture is good now ie full screen and sharp, I don't think it will
'collapse in' again.
I will see what it is like when it has been off over night to access
what difference it made.


When electronic things get better as they warm it's usually
associated
with tubes or electrolytic capacitors. Since your TV has only one
tube the CRT, it's plausible that it's at fault where focus is
concerned. When you first posted your chief complaint was that it
took
15 minutes to focus but only after you cleaned the anode cap. How
was
it before it started hissing?


There was no noticiable delay, by the time the picture was visable it
was
in focus.

I am not 100% clear about things but I think maybe
that the tape fixed it at first but the next day when I
switched on it hissed, I am not sure if it was also blurred,
my post seems to indicated it was only blurred after cleaning.
However I am not 100% sure of this.



I don't see a decent correlation between events here. Some may be
coincidental. I don't remember the age or brand of TV either. Was
that
ever mentioned?


TV is about 5 years old.
It's a Wharfdale :O)
Disturbingly similar to this one
http://www.unbeatable.co.uk/product/.../28143603.html
Wharfedale CTV2185RF

Comes with years guarantee, which is less that you are
entitled to under the law of the land - lol.

There may be a problem in that if theTV is
'warmed up' doing something to it like cleaninh
may not 'take-effect' blurring wise untill the next day.


Incidently I had this problem befo-

http://groups.google.co.uk/group/sci...pint&lnk=ol &

(im half_pint there).

Incidently the set did eventually go completely, but I
the problem was cured in the meantime, then one
day when, I switched on it just 'went', ie went dead,
no fireworks that I could see, just the normal click when you switch
on then nothing.

It worked for a while before it went, but not that long because
I have had this one for a while, I also got a portable
as a back-up :O).
I also have a USB TV stick I can use.

I will read up on this flyback stuff to see if I can make sense of it,
It might help me understand what is going on.


I am wondering if putting the back back on the TV will help
things?
I won't know untill the TV has been swiched off for a long time.

I guess LCD TV's don't have this problem?

TV is find at the moment, good picture.

I will time the warm up next time it has been off over night.





You should wait a day after you clean it to power it up. Especially if
you use a water based cleaner. And while it's sizzling it probably
will effect the focus.

I actually tried white spirit first (alcohol) but I don't think
it was that good so I used just water next, maybe with some
washing up liquid in it. I know tobacco smoke deposits seem
to be very water soluble.


Water is a good solvent. Some tars won't dissolve in ethyl alcohol but
most will in isopropyl or methyl alcohol. Personally I would have
started with testing a small area using a dab of Acetone on a rag.
If the surface seemed to tolerate that well then I would have wiped
around the anode cap for maybe 50 millimeters then the cap itself
provided it too was silicone rubber as Acetone doesn't react with 100%
silicone rubber readily.


Well...switched on this morning and.... no blurry picture!!!

However it was hissing a bit, I can't see no arcing however it's
hard to see with the back on, the hissing seems to have stopped now.

I thought putting the back on would help, I think the same happened
with my last TV but I can' remember clearly.
It seems to me it is effecting the capacitance in some way or whatever.

I an not sure about all this flyback stuuf and how it works
and why the tube is involved. Is the tube used as a smoothing capacitor?

Regarding solvents I know water works because I have to clean up
smoke deposits else where and I just use water and maybe some detergent.,
with white spirist everything smells of alcohol.


Well I can't remember when reinstalling a TV back sharpened up a focus
problem but I guess I've not seen every little oddity.

Well all the evidence I have seen is that it does!!
It was fine this morning, it hiss a bit but that has dissapeared totally.

I am tempted to take the back off again and see what it is like
when it fires up in the morning, however I don't think I have done
my back any favours lugging it up and down from it's normal resting spot.


I can perhaps see why it would cause a difference to the capacitive
characteristics
of the tube, particularly if the back is covered in smoke deposits.
I have a feeling I had the same with the old set, that is why I mentioned
it before I tried it I think.