Yikes! -- Actually that was not the intended tone of my post

PS --- Not being especially au fait with 'IM shorthand' - might I bother you for an expansion of "GF"?

IWHT: everyone knew that stood for Girl Friend.

But to a chav, it could mean: Great Fat..........................

 

IWHT: everyone knew that stood for Girl Friend.

But to a chav, it could mean: Great Fat..........................

Hmmm... I'd a feeling it didn't stand for 'general funds' in this context

Anyway, I won't let my 'lexical foibles' drive me further 'OT' -- @Aleph(0) please elucidate via PM...

 

Has anyone measure flyback transformer how much voltage output and how much current output.
mrel

 

Has anyone measure flyback transformer how much voltage output and how much current output.
mrel

I usually read the specifications off the schematic. If you have no written information, you can only look to the CRT image to see if the transformer is bad. They usually don't fail just a little bit.

You said you know the model number, but without the schematic I can only guess.
When I did this for a living, knowing the number of the CRT would tell me about what to expect.
That was over 40 years ago.

Maybe you could look up the CRT and deduce the expected voltages and currents from its specifications.

 

ERRATA RE: (my) Post #31 ---- Should have read "Should be ok so long as the resistor length ~ 5mm per kV of anticipated maximum EMF" --- as opposed to 400mm/KV!!! --- Methinks I've been downwind of "The Land of the Living Skies Burning Timber" too long...

Post amended!

 

Has anyone measure flyback transformer how much voltage output and how much current output.
mrel

A CTV usually has 24 - 25kV EHT, you can get a rough idea of current by looking at the cathode current specification in the CRT data sheet.

There's also the focus current etc, but that's a small fraction of the total.

Also bear in mind that most CRT TVs derived various supply rails from additional windings on the flyback transformer.

Usually at least the 200V or so for the video amplifiers, and almost always the 6.3V for the CRT heaters - monitors almost always don't use scan derived rails because the various VGA modes all produce different voltages.

 

@mrel monochrome CRTs run 12 to 20 kV, usually increasing voltage with decreasing spot size. Color tubes tend to be in the range of 20 kv to 30 kv (agreeing with ian field).

 

@mrel monochrome CRTs run 12 to 20 kV, usually increasing voltage with decreasing spot size. Color tubes tend to be in the range of 20 kv to 30 kv (agreeing with ian field).

Some of the "portable" mono sets that run off 12V were as low as 6kV - projections sets have separate R,G & B tubes that use somewhere around 30kV.

For a regular 3-colour tube, manufacturers try to keep it down to 24kV if they can because any higher increases X-ray emissions.

In the very early days the EHT was regulated by a dirty great 25kV shunt regulator triode - the whole line output stage was enclosed in a steel funnel to keep the X-rays down to a dull roar.

 

Some of the "portable" mono sets that run off 12V were as low as 6kV - projections sets have separate R,G & B tubes that use somewhere around 30kV.

For a regular 3-colour tube, manufacturers try to keep it down to 24kV if they can because any higher increases X-ray emissions.

In the very early days the EHT was regulated by a dirty great 25kV shunt regulator triode - the whole line output stage was enclosed in a steel funnel to keep the X-rays down to a dull roar.

Ian
I'm curious what happen if television is putting out X-Ray , but looking at television show 8 feet away would x-ray still be harmful or walking by a television that putting out x-ray would that be harmful.
Is there simple test to find out if television is putting out to much x-ray?
mrel

 

Some of the "portable" mono sets that run off 12V were as low as 6kV

Don't forget the Sony 'Watchman' hand-held BW CRT TV featuring an anode EMF of one kV!

http://pbacchiocchi.tripod.com/radios/watchman/crt.html

 

I'm curious what happen if television is putting out X-Ray , but looking at television show 8 feet away would x-ray still be harmful or walking by a television that putting out x-ray would that be harmful.
Is there simple test to find out if television is putting out to much x-ray?
mrel

As a practical matter the dose received from even a badly malfunctioning TV will not significantly exceed that from background sources... Moreover significant OV operation of the EHT supply will rapidly result in circuit/component failure (thus limiting your exposure)...

Of course it is good practice to verify the EHT following servicing as well as address symptoms of EHT supply malfunction (e.g. focus issues and 'blooming') in a timely fashion...

Best regards
HP

 

@mrel, all developed countries require that CRT displays be designed and certified to not generate X-rays in excess of am acceptable limit. The limits are low enough m(0.5 mR/hr in the U.S.) so that people could sit in front of computer monitors all day every day with little increase in risk of harm from ionizing radiation.

 

Ian
I'm curious what happen if television is putting out X-Ray , but looking at television show 8 feet away would x-ray still be harmful or walking by a television that putting out x-ray would that be harmful.
Is there simple test to find out if television is putting out to much x-ray?
mrel

The manufacturers were aware of potential problems, and took steps to minimise them.

Early CTV sets had heavy shielding around the horizontal output stage, and CRTs were made of glass with a high lead content - something that is now (allegedly) causing environmental problems with electronic waste disposal.

I bet if you asked the morons in Brussels where lead came from in the first place - they wouldn't have the faintest clue!

In Britain; they're still finding old Roman lead water channeling, and they never did eliminate all the old lead water pipes back in the 60s.

Getting lead out of petrol was a good idea though - the petrochemical industry annual procurement of lead was in the thousands of tons, all of which ended up as exhaust particulates in the air we breath.