Weirdest problem

[Sal M. Onella]

Xray detector???

In a TV??????
What planet are you from?

Some TV's have an overvoltage detector in the HV cage which shuts down the
HV if
it goes so high as to be capable of producing xrays.

Should have been called X-ray Producing Voltage Risk Level Exceeding
Detector, but unfortunately the
"Röntgenstrahl, Spannung Gefahr Waagerecht ausgerichteten Außerordentlichen
Detektor Produzierend"
sticker on the back of the German model blocked all the air holes, so they
had to shorten it.

 

[Albert Manfredi]

Then why not say so? A rectifier isn't a capacitor, and a capacirtor isn't a
rectifier. If you think I'm being pedantic

He was obviously referring to an electrolytic filter capacitor in the
rectifier circuit. It's not "pedantic," as much as "unnecessarily
aggressive."

to worry about the distinctions
between different electronic components, that's nothing to the behaviour of
the circuitry itself. If you wire up the wrong components in the wrong way it
simply won't work.


Yes, sometimes I hate them too.

I never bought this thermal problem theory, at least not the normal sort
of thermal problem. I think that having to wait 48 hours for the thing
to cure itself makes this heating theory questionable indeed. Anything's
possible, I suppose, but to claim this screams of thermal problem is
overstated. If it were a matter of 15 minutes or even one hour, maybe

Seriously, the most common problem with electrolytics is that the electrolyte
dries up and the component goes low in value. the big ones in the power supply
going low like this would probably result in mains hum - light or dark bars
slowly drifting up and down the screen, or audible 50Hz/60Hz hum from the
loudspeaker.

Yeah, that's the most common. Possibly, the thing could short out after
being turned off? And if the power supply has a protection circuit,
rather than a fuse, it could keep this power supply shut down? Maybe the
electrolyte needs 48 hours to ooze back where it belongs? I don't know
how likely this is, but it seems every bit as likely as any "thermal
problem," and frankly, more so.

Bert

 

[Jan Panteltje]

Xray detector???

Some TV's have an overvoltage detector in the HV cage which shuts down the
HV if
it goes so high as to be capable of producing xrays.

Should have been called X-ray Producing Voltage Risk Level Exceeding
Detector, but unfortunately the
"Röntgenstrahl, Spannung Gefahr Waagerecht ausgerichteten Außerordentlichen
Detektor Produzierend"
sticker on the back of the German model blocked all the air holes, so they
had to shorten it.

I happen to read fluently German, but this makes not a lot of sense.
On some TVs Röntgen radiation was possible, especially the old
tubed ones that had a PD100 paralel stabilizer, the glass would become all
colored.
However these were in a metal cage (with safety switch).
From the CRT itself nothing could be measured, I have had some TVs with
defective HV regulator, perhaps going up to above 35kV, you will get ozone,
but I would not worry about radiation in front of the tube.
As for 'horizontally aligned' well, in Germany long time ago (80ties) they had
'Högbild' TV for fun, you had to put the TV on the side.
JP

 

[Andrew VK3BFA]

????????????Xray detector???
In a TV??????
What planet are you from?
JP

Jan,
review your basic physics theory - at more than 25Kv the CRT will
generate X-rays , all TV sets have a monitoring cct to shut them down
if this happens.

Barbara,
quite happy to help you troubleshoot this thing - I am a working TV
technician and this is a bread and butter fault. What is the model,
what is the chassis type - may be able to cross reference it to
Samsung sold here. Are you competent in basic electronics and HV
safety precautions - do you own a soldering iron and a multimeter - I
dont want the responsibilty of you killing yourself if you are a
beginner.

Samsungs of that vintage had poor power supply design problems, fixed
by upgrading via a Samsung kit.

Of more concern is that Samsung have traditionally had poor CRT's
with a short life (they skimped on cathode coating in the RGB guns) -
when it was working, are you quite happy with the quality of the
picture - if the answer is "NO" then bin it and buy a new one.

Seven years from any TV set is a good run, most die at the 3-5 year
mark, depends on number of hours on it.

73 de VK3BFA Andrew

 

[Sal M. Onella]

On a sunny day (Fri, 4 Jun 2004 16:44:17 -0700) it happened "Sal M. Onella"
I happen to read fluently German, but this makes not a lot of sense.
On some TVs Röntgen radiation was possible, especially the old
tubed ones that had a PD100 paralel stabilizer, the glass would become all
colored.
However these were in a metal cage (with safety switch).
From the CRT itself nothing could be measured, I have had some TVs with
defective HV regulator, perhaps going up to above 35kV, you will get ozone,
but I would not worry about radiation in front of the tube.
As for 'horizontally aligned' well, in Germany long time ago (80ties) they had
'Högbild' TV for fun, you had to put the TV on the side.
JP

I'm sorry Jan, but that was an attempt at humor. I was playing off three
things:
1) the guy who didn't like the phrase "X-ray detector"
2) renaming the "X-ray Detector" more completely
3) the complexity of translating long names into another language.

I just made up a very long version of "X-ray Detector" and used an Internet
site to give me the words in German, which I do not speak or read. I
thought
the mention of the sticker blocking all the air holes would surely give
away the joke, but it was not to be.

I believe the "horizontal" reference came to be from the word "level" which
might be translated variously, depending on context.

No joke is funny if you have to explain it. Sorry to all.

 

[Rich Grise]

Entire outside of picture tube may be, and much of it will be,
connected to rectified HV from flyback. If B&W 10-15kV, if
color, at least 22kV and probably closer to 30kV or more when
operating. HV caps likely not fully discharged when beast is off.

It had better not be!

The big red cup and red wire cover up the lead that goes to the
anode. The HV is inside that. The outside of the glass is covered
with a conductive coating that's grounded. The HV cage should
be fully covered; so with the exception of the "mains" line in,
the B+, the neck board, and the deflection, it should be relatively
safe to poke around with it PROVIDED:
No jewelry.
Keep one hand in pocket.
If possible, keep one finger of working hand in contact with
some kind of ground - that way if you get zapped, just the hand
gets it, not the whole body (the current would be about the
same, believe it or not. Inside the skin, human-stuff is a
very good conductor. Ions, you know. ).

Good Luck!
Rich

 

[maxfoo]

The most effective solution can be had for about $119 at most big retail
places. All new parts, no dust, a warranty of sorts, no effort and it
will work.
Now if you are a hobbyist maybe you have an endless cost limit for
learning something new.
I hate to promote the "throw-away society" but maybe you should write a
letter to the factory commending them about how this set lasted 7 years.
Well, maybe not because that would further encourage them.
Seven years out of a 13" Samsung set ain't so bad.

-BM

Next time buy a Sharp 13" TV, I bought one in 1983 and it still works
beautifully...never had a problem!





















Remove "HeadFromButt", before replying by email.

 

[Jan Panteltje]

Jan,
review your basic physics theory - at more than 25Kv the CRT will
generate X-rays , all TV sets have a monitoring cct to shut them down
if this happens.

No they don't.
neither does your CRT monitor (have such a device).
You know nothing about TV electronics it seems.
JP

 

[Jan Panteltje]

It had better not be!

The big red cup and red wire cover up the lead that goes to the
anode. The HV is inside that. The outside of the glass is covered
with a conductive coating that's grounded. The HV cage should
be fully covered; so with the exception of the "mains" line in,
the B+, the neck board, and the deflection, it should be relatively
safe to poke around with it PROVIDED:
No jewelry.
Keep one hand in pocket.
If possible, keep one finger of working hand in contact with
some kind of ground - that way if you get zapped, just the hand
gets it, not the whole body (the current would be about the
same, believe it or not. Inside the skin, human-stuff is a
very good conductor. Ions, you know. ).

Good Luck!
Rich

Yes, but it is tricky, I did discharge large CRTs that way, took them out
(for replacement), and then got zapped while holding them (you should be
VERY steady and not drop it in such a case).
This seems to be because the HV connection sort of charges up again,
maybe some late electrons...
JP

 

[Mat Nieuwenhoven]

On 4 Jun 2004 18:16:33 -0700, Andrew VK3BFA wrote:

Seven years from any TV set is a good run, most die at the 3-5 year
mark, depends on number of hours on it.

3-5 years? I don't think I ever had a failure before 7 years, and the picture
became unusable after 12 or so (especially on Sony). This is with running the
TV only when actually watching, not using it as 'moving wallpaper', so lets
say an average of 4 hours per day. And I know people who's TVs (Philips, 3
subsequent models) lasted longer than 15 years without failure and with long
daily hours. If a TV failed after 3 years the vendor has to fix it, by law
here you can expect a decent life from a product, and 3 years is not decent.

Mat Nieuwenhoven

 

[Fred Bloggs]

Entire outside of picture tube may be, and much of it will be,
connected to rectified HV from flyback. If B&W 10-15kV, if
color, at least 22kV and probably closer to 30kV or more when
operating. HV caps likely not fully discharged when beast is off.

Add that cheap appliances often have AC mains come in w/o
transformer...

1) treat as High Voltage issue:
a) one hand rule (only use one hand at a time, keep other in pocket or behind back)
b) lone worker rule (NEVER work alone on HV, even unenergized circuits)
c) short out HV caps before proceeding and KEEP SHORTED during process

above are specific recommendations above and beyond normal safety rules

N.B., these procedures should be followed even if all you are doing is
taking the cover off and peering into to !@#$%^ thing

Take a lesson from the aviation community:
There are OLD pilots
and there are BOLD pilots
but there are NO OLD, BOLD pilots.

DO NOT TRUST GLOVES to keep you insulated from HV.

Please cite for me any news article of anyone being electrocuted by TV
set- it just doesn't happen. The only hazard I am aware of is drunks
starting fires by throwing liquor bottle through CRT

 

[Jan Panteltje]

On 4 Jun 2004 18:16:33 -0700, Andrew VK3BFA wrote:



3-5 years? I don't think I ever had a failure before 7 years, and the picture
became unusable after 12 or so (especially on Sony). This is with running the
TV only when actually watching, not using it as 'moving wallpaper', so lets
say an average of 4 hours per day. And I know people who's TVs (Philips, 3
subsequent models) lasted longer than 15 years without failure and with long
daily hours. If a TV failed after 3 years the vendor has to fix it, by law
here you can expect a decent life from a product, and 3 years is not decent.

Mat Nieuwenhoven

Confirmed
JP

 

[Joseph Hansen]

(for replacement), and then got zapped while holding them (you should be
VERY steady and not drop it in such a case).
This seems to be because the HV connection sort of charges up again,
maybe some late electrons...
JP

Um, beg to differ with the "charges up again" statement. If you discharged
it and then got zapped, you just didn't do a good job of discharging it...
maybe because of your equipment, or maybe because of your technique. I was
a tv tech for two years, then a monitor repair tech for nine more. I know.

Aside from that, if this person's problem involves going anywhere near that
HV cap... then she needs to discard the tv and buy a new one. The picture
tube is not a user serviceable part. Heck, it's barely a technician
serviceable part.

 

[Jan Panteltje]

Um, beg to differ with the "charges up again" statement. If you discharged
it and then got zapped, you just didn't do a good job of discharging it...

Normally I would shorrt it to ground for say a few seconds.
But if you wait a while there will be charge again.

maybe because of your equipment, or maybe because of your technique. I was
a tv tech for two years, then a monitor repair tech for nine more. I know.

I have more years....
Repaced more tubes then I can remember..

Aside from that, if this person's problem involves going anywhere near that
HV cap... then she needs to discard the tv and buy a new one.

????
We are talking workshop here.

The picture
tube is not a user serviceable part. Heck, it's barely a technician
serviceable part.

Tell my old neighbour!
hehe
he had a horizontal line, some genius told him: 'Its the tube'
so he took it out, got a new one from somewhere, it made no difference,
then knocked on my door, I replaced the 1 cent resistor and it worked again.
So do not assume 'users' do not do things, where I am they strip their car
to the last bolt too, including the engine.
JP

 

[Joseph Hansen]

No they don't.
neither does your CRT monitor (have such a device).
You know nothing about TV electronics it seems.
JP

Um, no they don't what? Generate x-rays? Well, I'd have to disagree with
you on that, Andrew. Jan is right. They can -- if the voltage gets high
enough, which it is kept from doing by a circuit that monitors it and shunts
it to ground if it gets too high. It doesn't generally shut the tv down...
just prevents that voltage from going high enough to cause x-rays. If you
shoot a high energy electron beam (you give it higher energy by increasing
the potential) at a metal target, the metal target will emit x-rays. Basic
x-ray theory. (I was an x-ray machine repairman for the army for a while)
It just takes a higher voltage than is used in an average tv. When you were
a kid, didn't your mother tell you not to sit too close to your tv? That's
because she had heard that a television will emit low end x-rays. Because
back then they didn't build prevention into them. Incidentally, the lower
the energy level of an x-ray the more likely it will be to injure the body.
There were kids who ended up with cancer in their feet at that time, because
they would lay with their feet next to the set and watch hours of tv.

If you can't detect any x-rays now, that's because the circuitry to prevent
them is working properly. Also, you may have been measuring at the front of
the picture tube... but those are made of leaded glass (to stop the x-rays)
so they don't emit much in that direction. The glass of the bell and neck,
however, is not leaded, and also is much thinner. Even with the old sets,
the x-rays were emmited mostly out the back of the set. Now you will often
see a metal shell surrounding the bell of a larger set. That is because the
larger picture tube requires a higher voltage in order to accelerate the
beam properly, and they can emit. So they add the shield to catch any stray
x-rays.

You shouldn't accuse people of not knowing something that you don't know.
It can backfire on you.

 

[Julie]

I have a solid-state TV receiver Samsung model TOD1841 13" color
receiver about 7 or 8 years old.
with remote control. which has functions like alarm, scheduled turn off etc
(irrelevant for the
issue here but just describing the state of the art on it)

I can turn it ON & it works ok until I turn it OFF ( either manually or
with remote ) .
Then I cannot turn it ON for at least what seems like about 48 hours.
Then the same cycle repeats

Has anyone seen this ? So weird ?

Check the main power relay. The contacts can become corroded or fused.

Before servicing TVs, make sure that you take all necessary precautions,
including discharging the CRT and wearing safety goggles.

 

[Julie]

Check the main power relay. The contacts can become corroded or fused.

Before servicing TVs, make sure that you take all necessary precautions,
including discharging the CRT and wearing safety goggles.

Follow-on: before opening up the set, when in the failed state, try repeatedly
& constantly turning on the TV for a couple of minutes. If it does turn on
during that time, then the relay is highly suspect.

 

[Activ8]

I'm sorry Jan, but that was an attempt at humor. I was playing off three
things:
1) the guy who didn't like the phrase "X-ray detector"
2) renaming the "X-ray Detector" more completely
3) the complexity of translating long names into another language.

I just made up a very long version of "X-ray Detector" and used an Internet
site to give me the words in German, which I do not speak or read. I
thought
the mention of the sticker blocking all the air holes would surely give
away the joke, but it was not to be.

I believe the "horizontal" reference came to be from the word "level" which
might be translated variously, depending on context.

No joke is funny if you have to explain it. Sorry to all.

No need to apologize to me. I though it was funny.

 

[Activ8]

Jan,
review your basic physics theory - at more than 25Kv the CRT will
generate X-rays , all TV sets have a monitoring cct to shut them down
if this happens.

Barbara,
quite happy to help you troubleshoot this thing - I am a working TV
technician and this is a bread and butter fault. What is the model,
what is the chassis type - may be able to cross reference it to
Samsung sold here. Are you competent in basic electronics and HV
safety precautions - do you own a soldering iron and a multimeter - I
dont want the responsibilty of you killing yourself if you are a
beginner.

Samsungs of that vintage had poor power supply design problems, fixed
by upgrading via a Samsung kit.

Of more concern is that Samsung have traditionally had poor CRT's
with a short life (they skimped on cathode coating in the RGB guns) -
when it was working, are you quite happy with the quality of the
picture - if the answer is "NO" then bin it and buy a new one.

Seven years from any TV set is a good run, most die at the 3-5 year
mark, depends on number of hours on it.

73 de VK3BFA Andrew

Hah! Now days yes. I just had to replace one that's probably 20 yrs
old or so.

 

[Activ8]

No they don't.
neither does your CRT monitor (have such a device).
You know nothing about TV electronics it seems.
JP

Hey shit for brains. Speak for yourself.