Picture Tube Hazards

[Scott]

I have a TV/DVD/VCR combo. The DVD player started skipping and just
totally went out. I suspect that the lens is dirty but in order to clean
it I have to remove the DVD unit from the TV. There are a couple of
screws right below the picture tube that are going to be hard to reach.
My question is it ok if I touch the bottom of the tube and not get
electrocuted. I know about the hazards of touching the thick wire on top
of the tube but unsure about the tube itself.

-ss

 

[Meat Plow]

I have a TV/DVD/VCR combo. The DVD player started skipping and just
totally went out. I suspect that the lens is dirty but in order to clean
it I have to remove the DVD unit from the TV. There are a couple of
screws right below the picture tube that are going to be hard to reach.
My question is it ok if I touch the bottom of the tube and not get
electrocuted. I know about the hazards of touching the thick wire on top
of the tube but unsure about the tube itself.

-ss

Just don't come close to the area around that "thick wire" and you should
be ok. And watch the other circuitry, avoid using both hands if you can,
make sure the thing isn't plugged in.

 

[JANA]

There are proper procedures to remove the DVD player section. It requires
some disassembly. TV service tech's do this type of work all the time, and
there are no hazards.

You should NOT be messing around in your TV set. Your safest procedure is to
give it out to a service shop that services TV sets, and have them do the
work. This way, it will be responsibly performed, and there will not be any
possible safety issues after assembly, and when you are using the unit.

--

JANA
_____


I have a TV/DVD/VCR combo. The DVD player started skipping and just
totally went out. I suspect that the lens is dirty but in order to clean
it I have to remove the DVD unit from the TV. There are a couple of
screws right below the picture tube that are going to be hard to reach.
My question is it ok if I touch the bottom of the tube and not get
electrocuted. I know about the hazards of touching the thick wire on top
of the tube but unsure about the tube itself.

-ss

 

[Scott]

There are proper procedures to remove the DVD player section. It requires
some disassembly. TV service tech's do this type of work all the time, and
there are no hazards.

You should NOT be messing around in your TV set. Your safest procedure is to
give it out to a service shop that services TV sets, and have them do the
work. This way, it will be responsibly performed, and there will not be any
possible safety issues after assembly, and when you are using the unit.

I know what you mean but then I will have to bring my heavy TV to the
shop (which is even harder since I don't have a truck), possibly wait a
few days in which I won't have a TV and then get charge an arm and a
leg...just to have my lens clean! I think I'll take my chances. That's
what I get for buying a TV/DVD/VCR combo.

 

[Arfa Daily]

I know what you mean but then I will have to bring my heavy TV to the shop
(which is even harder since I don't have a truck), possibly wait a few
days in which I won't have a TV and then get charge an arm and a
leg...just to have my lens clean! I think I'll take my chances. That's
what I get for buying a TV/DVD/VCR combo.

To be honest, you are likely to be wasting your time getting to the lens to
clean it, as this is highly unlikely to be your problem unless a) you live
in a very smoky house, or b) you've recently had some dusty building work
done. Unlike with a CD player, normal household dust tends not to deposit on
the lens of a DVD deck, because of the extremely high rotational speed of
the disc, compared to a CD deck. This causes a layer of air to be dragged
round under the disc at high speed, which tends to keep the lens dust-free.
From years of experience repairing DVD players, it is far more likely that
you have a worn laser ( or possibly, but less likely ) a worn spindle motor.
If the unit plays CDs without skipping, then you can be reasonably sure that
it is a laser issue.

Arfa

 

[Scott]

To be honest, you are likely to be wasting your time getting to the lens to
clean it, as this is highly unlikely to be your problem unless a) you live
in a very smoky house, or b) you've recently had some dusty building work
done. Unlike with a CD player, normal household dust tends not to deposit on
the lens of a DVD deck, because of the extremely high rotational speed of
the disc, compared to a CD deck. This causes a layer of air to be dragged
round under the disc at high speed, which tends to keep the lens dust-free.
From years of experience repairing DVD players, it is far more likely that
you have a worn laser ( or possibly, but less likely ) a worn spindle motor.
If the unit plays CDs without skipping, then you can be reasonably sure that
it is a laser issue.

Arfa

It started skipping when I was playing a CD. It has been exposed to a
lot of smoke from people exhaling towards the TV. I'm prepare for the
worst anyways, just in case the DVD unit is bad I already have the
replacement # from Panasonic($110). So either way I have to pull the
unit out.

-ss

 

[jakdedert]

To be honest, you are likely to be wasting your time getting to the lens to
clean it, as this is highly unlikely to be your problem unless a) you live
in a very smoky house, or b) you've recently had some dusty building work
done. Unlike with a CD player, normal household dust tends not to deposit on
the lens of a DVD deck, because of the extremely high rotational speed of
the disc, compared to a CD deck. This causes a layer of air to be dragged
round under the disc at high speed, which tends to keep the lens dust-free.
From years of experience repairing DVD players, it is far more likely that
you have a worn laser ( or possibly, but less likely ) a worn spindle motor.
If the unit plays CDs without skipping, then you can be reasonably sure that
it is a laser issue.

Maybe they're just living on borrowed time, but I've fixed a number of
them by cleaning the lens. I'd say it was the smokey environment in my
house, but at least a couple of them were second-hand from others.

jak

 

[Arfa Daily]

It started skipping when I was playing a CD. It has been exposed to a lot
of smoke from people exhaling towards the TV. I'm prepare for the worst
anyways, just in case the DVD unit is bad I already have the replacement #
from Panasonic($110). So either way I have to pull the unit out.

-ss

You may be lucky then, and a clean of the lens might restore it - for a
while at least, and assuming that it's not a computer-style IDE type drive.
Cleaning never seems to help with these. Clean the lens with a cotton bud
(Q-Tip) moistened with electronics grade (99.7% + ) isopropyl alcohol.
Polish with a dry cotton bud. Don't be tempted to adjust any pots mounted on
the laser. Mis-adjustment of them is likely to result in rapid destruction
of the laser diode(s).

If the price you have from Pan is for just a laser, rather than a
pre-assembled sub deck, be aware that most Pan DVD players, require
mechanical adjustment of the tilt and skew after the laser is fitted.
Provided that the model in question has the jitter meter software built in,
this is not difficult, if a little fiddly.

Arfa

 

[James Sweet]

I have a TV/DVD/VCR combo. The DVD player started skipping and just totally
went out. I suspect that the lens is dirty but in order to clean it I have
to remove the DVD unit from the TV. There are a couple of screws right
below the picture tube that are going to be hard to reach. My question is
it ok if I touch the bottom of the tube and not get electrocuted. I know
about the hazards of touching the thick wire on top of the tube but unsure
about the tube itself.

-ss

Yeah you'll be fine. Take care not to damage the delicate neck and connector
pins of the picture tube, if you crack the glass and let air in, the tube is
toast.

 

[Scott]

You may be lucky then, and a clean of the lens might restore it - for a
while at least, and assuming that it's not a computer-style IDE type drive.
Cleaning never seems to help with these. Clean the lens with a cotton bud
(Q-Tip) moistened with electronics grade (99.7% + ) isopropyl alcohol.
Polish with a dry cotton bud. Don't be tempted to adjust any pots mounted on
the laser. Mis-adjustment of them is likely to result in rapid destruction
of the laser diode(s).

If the price you have from Pan is for just a laser, rather than a
pre-assembled sub deck, be aware that most Pan DVD players, require
mechanical adjustment of the tilt and skew after the laser is fitted.
Provided that the model in question has the jitter meter software built in,
this is not difficult, if a little fiddly.

Arfa

Thanks for all the info! It has a IDE connector on the back so I'm
assuming it's IDE. Also the price from Panasonic is for the whole unit.

 

[Arfa Daily]

Thanks for all the info! It has a IDE connector on the back so I'm
assuming it's IDE. Also the price from Panasonic is for the whole unit.

Yeah, I kinda suspected that might be the case, which is why I made the
comment. In that case, I think, from experience, that you are unlikely to
recover it with cleaning. As these drives are pretty much totally enclosed,
anything like cigarette smoke has a tendency to condense out on the outside
of the drive, rather than on internal components. I think that in the end,
you will finish up replacing the whole drive, as you felt that you might
have to.

Arfa

 

[Michael Kennedy]

Yeah, I kinda suspected that might be the case, which is why I made the
comment. In that case, I think, from experience, that you are unlikely to
recover it with cleaning. As these drives are pretty much totally
enclosed, anything like cigarette smoke has a tendency to condense out on
the outside of the drive, rather than on internal components. I think that
in the end, you will finish up replacing the whole drive, as you felt that
you might have to.

Arfa

Well if it is IDE could he just purchase a cheap computer DVD drive and put
it in there? I'd try that, but I have no expierence with dvd players that
use IDE drives and don't know if it would work.

Mike

 

[Arfa Daily]

Well if it is IDE could he just purchase a cheap computer DVD drive and
put it in there? I'd try that, but I have no expierence with dvd players
that use IDE drives and don't know if it would work.

Mike

Hi Mike. I only ever tried it once. I can't remember the make, but I seem to
think that it might have be a Sammy or a Tosh. Anyway, whichever, it didn't
work. I remember asking the technical boys at whichever it was, why it
didn't work, and they said it was a software thing. That somehow the
player's operating system could recognise a 'correct' drive. I guess all CD
/ DVD drives have some type of readable model designator and serial number
as part of their own controller's software, so maybe the machine's OS was
programmed to evaluate this, or maybe the drives were even an OEM version
'customed' for recognition in these machines.

On the other hand, some time ago, I did a Yamaha hard disc recorder where
the drive had failed. Looked like a pretty much standard IDE drive. We
contacted Yammy to get a price on a replacement drive, and after the guy
finished laughing at our sharp intake of breath, he told us that to be
honest, we could put any old drive of the same size in it, but preferably
one of the same make as well. So we ordered one off a computer supplies
company for about a fifth the cost, flung it in, and away it went, good as
gold. So the short answer is, I really don't know. I would be a bit
reluctant to say that it's worth a go, for fear of corrupting the machine's
software. There have been many cases where people have tried to make
machines multi-region or region-free, by following either half-arsed
internet instructions, or Honest Harry's Mod Tips page in DVD Hackers'
Weekly, and ended up with unrecoverable corupted software, rendering their
pride and joy useless, and outside of warranty ...

At the end of the day, 110 bucks is not the end of the world, and if I was
the OP, I think that I would feel happiest just dropping in a manufacturer's
official replacement part.

Arfa

 

[JANA]

Another thought. There are Laser cleaning CD kits on the market. It has
little brushes in the disk, and you can simply put a drop of the cleaner on
to the brushes, that comes with it. Follow the instructions.

Most of the time, in these units skipping is a warn laser.

--

JANA
_____

To be honest, you are likely to be wasting your time getting to the lens
to
clean it, as this is highly unlikely to be your problem unless a) you live
in a very smoky house, or b) you've recently had some dusty building work
done. Unlike with a CD player, normal household dust tends not to deposit
on
the lens of a DVD deck, because of the extremely high rotational speed of
the disc, compared to a CD deck. This causes a layer of air to be dragged
round under the disc at high speed, which tends to keep the lens
dust-free.
From years of experience repairing DVD players, it is far more likely that
you have a worn laser ( or possibly, but less likely ) a worn spindle
motor.
If the unit plays CDs without skipping, then you can be reasonably sure
that
it is a laser issue.

Arfa

It started skipping when I was playing a CD. It has been exposed to a
lot of smoke from people exhaling towards the TV. I'm prepare for the
worst anyways, just in case the DVD unit is bad I already have the
replacement # from Panasonic($110). So either way I have to pull the
unit out.

-ss

 

[Scott]

Another thought. There are Laser cleaning CD kits on the market. It has
little brushes in the disk, and you can simply put a drop of the cleaner on
to the brushes, that comes with it. Follow the instructions.

Most of the time, in these units skipping is a warn laser.

I tried that already with no success. I even tried compressed air. Also
the player is only 1.5 years old. I've probably only play around 50
DVD's and a few CD's during that time.

 

[Arfa Daily]

Another thought. There are Laser cleaning CD kits on the market. It has
little brushes in the disk, and you can simply put a drop of the cleaner
on
to the brushes, that comes with it. Follow the instructions.

Most of the time, in these units skipping is a warn laser.

You are brave to recommend these !

IMHO, if you want to do no good at all at best, and actually damage the
laser at worst, use a cleaning disc with little brushes on it ... On several
occasions, I have seen an otherwise good laser wrecked by the brush getting
caught in the lens suspension, and tearing this off with the high rotational
speed of a DVD. As I have said on many occasions, it is rare for DVD lasers
to suffer from dust like CD lasers. Even on CD lasers, the cleaning discs do
little good, as the brush bristles are deflected by the 'wall' around the
lens periphery, which is a typical design shape of a CD laser's lens.

Arfa

 

[Scott]

You are brave to recommend these !

IMHO, if you want to do no good at all at best, and actually damage the
laser at worst, use a cleaning disc with little brushes on it ... On several
occasions, I have seen an otherwise good laser wrecked by the brush getting
caught in the lens suspension, and tearing this off with the high rotational
speed of a DVD.

Don't tell me that But since a laser cleaning CD kit is a 'CD'
wouldn't the DVD player use the rotational speed for a CD?

 

[bz]

Yeah you'll be fine. Take care not to damage the delicate neck and
connector pins of the picture tube, if you crack the glass and let air
in, the tube is toast.

Not to mention the mess that the 15 psi on each square inch of the tube can
make if you 'get lucky' and shatter the tube. Kind of like a grenade going
off. It can throw glass for quite some distance.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap

 

[Arfa Daily]

Don't tell me that But since a laser cleaning CD kit is a 'CD' wouldn't
the DVD player use the rotational speed for a CD?

Well, once it has determined that it *is* a CD, it might, but there are a
couple of qualifiers here. Firstly, most DVD players assume a DVD first, so
spin up to full speed in readiness for that. They only then slow back down
to CD speed, once they've determined that the data streaming off the disc is
CD audio, not DVD video and audio. Secondly, some DVD players run CDs at
full speed also, much like a personal CD player runs the disc at high speed,
when in anti-shock mode ( to keep the bit bucket full ). Thirdly, some
players have a lot of trouble making any sense of a cleaning disc. I don't
know whether this is an issue with the data contained on them, or whether
it's an issue with the brushes whacking the lens on every rotation, and
vibrating it about its correct focus point. Whatever it is anyway, some
players just will not lock their spindle servos on these discs, and they
just run at very high speed, totally out of control. At the end of the day,
the only way to clean a laser lens, is 'properly' - that is by hand,
carefully, with nothing more aggressive than electronics grade IPA. Even
then, any improvement may be only marginal or temporary as, if dust on the
lens was the primary cause of whatever problem was apparent, the chances are
that there is also dust on the critical angle mirror and the face of the
pickup photodiode array, both of which are internal components of the
optical block ( laser ) that you can't get at to clean. And again, DVD
lasers seldom collect dust on their lens, due to the blanket of air dragged
round under the disc, by its high rotational speed.

Arfa

 

[Sam Goldwasser]

Another thought. There are Laser cleaning CD kits on the market. It has
little brushes in the disk, and you can simply put a drop of the cleaner on
to the brushes, that comes with it. Follow the instructions.

Most of the time, in these units skipping is a warn laser.

And those lens cleaning CDs/DVDs may do more harm than good.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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