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Crt and x-ray radiation

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slowcade View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slowcade Quote  Post ReplyReply Direct Link To This Post Topic: Crt and x-ray radiation
    Posted: 19 Feb 2018 at 6:44pm
I have never considered this much before, but a recent YouTube video made me think..
How dangerous can a crt arcade monitor be? Let's say that an operator/technician had disabled all the x-ray protection circuits? Or if you buy a cheap generic China chassis? Or if something goes wrong?
Is there a tiny chance that you get an unhealthy dose of radiation?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Flinnster Quote  Post ReplyReply Direct Link To This Post Posted: 19 Feb 2018 at 7:31pm
Oh well, I'm probably screwed.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote martin8or Quote  Post ReplyReply Direct Link To This Post Posted: 19 Feb 2018 at 8:21pm
As far as I know you need several 10's of kilovolts to produce x-rays which is way above most crt's operating voltages.
There's no danger,it's just an old wives tale mostly. Some electrostatic displays could probably get high enough and the occasional 50's vintage black and white tv (depending on valve configuration in the high voltage section) and possibly some crt based rear projection colour tv's were a high enough voltage but most things you would come across wouldn't produce any x-rays.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArcadeHacker Quote  Post ReplyReply Direct Link To This Post Posted: 19 Feb 2018 at 9:06pm
The impact of electrons at CRT energy levels should produce xrays, the glass in your CRT has lead in it to block those from reaching you. 

I have the equipment to detect and measure xrays and can do an experiment to see how much a CRT leaks out (if anything). I'll do some testing over the weekend and report back. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanH Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 1:18am
Don't worry, unless your head is pressed against the screen for years you'll be fine, just more internet bollocks.
I still have a crt tv, my mams been a user of crt TV's since they were first produced and she 83 now, so I don't think there be much to worry about..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jugemscloud Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 2:08am
this reminds me of a query i got a long time ago just after Fukushima nuclear plant disaster where someone wanted assurances that the games i were selling had been exported before the disaster Ermm

i can just see all us collectors glowing in the dark come our old age and our partners unable to get to sleep due to it, thinking back on how we should have heeded this warning LOL

at least well save money on batteries for torches LOL


Edited by jugemscloud - 20 Feb 2018 at 2:13am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slowcade Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 5:51am

The specific reason why I'm asking is because Arcade Jason mentioned that using a chassis made for a large tube on a smaller tube could lead to some radiation.
And that made me curious, so I googled and found this article:
http://www.electronicrepairguide.com/monitor-high-voltage.html

Warning!!!!

If you come across any Monitor/Television that have the high voltage shutdown problem and you can’t find out the cause then please do not disable the X-ray protection pin at the horizontal/oscillator IC or modify the circuit because it will be very dangerous to USER! If you can’t repair the Monitor just send back to the customer or send it to someone that can do the job. It is wrong (not ethical) to do such a job that put the user in a high risk situation just for the purpose of earning some profit!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Bennett Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 6:45am
https://www.repairfaq.org/samnew/tvfaq/tvaihxray.htm

You'd have to have a double failure (HV regulation and this circuit) for anything to happen.

Probably just a smidge over some (very) safe radiation threshold - can't imagine it'd put an image of your bones onto the wall behind, or do a Dr Spock.

Edited by John Bennett - 20 Feb 2018 at 6:47am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Arch Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 8:35am
CRT radiation is my only chance of getting a decent tan. LOL

But seriously, what AJ says in that video is that there has to be a serious mismatch between chassis and screen for that to occur, say by using a 36" chassis on a 14" screen. Which probably isn't a good idea anyway.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slowcade Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 10:06am
That's probably true. But I was surprised that he said that there is a potential health risk.
Let's say that I purchase a cheap generic Chinese chassis. How do I identify if it includes an x-ray protection circuit?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kidyamlo Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 10:57am
Speaking as a semi-pro hypochondriac (so not wishing to belittle your concerns, because weird sh*t does happen and one's cumulative "lifetime" exposure to radiation is broadly calculable and important to ponder, at least once in a while) you're more likely to develop something nasty by other means. At the age of nine my brother drank a thermometer full of mercury - just to see what would happen, as you do - and he's still walking around at the age of 40. You don't get any more Homer Simpson than that. I guess he still has time to see what might go wrong...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Bennett Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 11:58am
Originally posted by slowcade slowcade wrote:

That's probably true. But I was surprised that he said that there is a potential health risk.
Let's say that I purchase a cheap generic Chinese chassis. How do I identify if it includes an x-ray protection circuit?


The circuit only kicks-in when the HV regulation goes faulty, so you'd presumably see that in the screen brightness going off-the-scale
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brettster Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 12:28pm
Time to fire up the old Radiation King


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Post Options Post Options   Thanks (0) Thanks(0)   Quote slowcade Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 1:17pm
Ok ok, you have convinced me. I'll buy some universal chassis from Taobao.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kidyamlo Quote  Post ReplyReply Direct Link To This Post Posted: 20 Feb 2018 at 1:20pm
Your mileage may vary; caveat emptor, etc...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote IanH Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb 2018 at 11:48pm
I bet you get more way more em radiation from your mobile phone than you would from a crt tube.

Don't worry.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote andrewsm Quote  Post ReplyReply Direct Link To This Post Posted: 22 Feb 2018 at 12:05am
You can generate Xrays with as little as 20Kv which is within the Colour CRT voltage range. If the boost voltage is turned up too much then there is a risk of xrays from the neck of the tube as they bounce back from the electrodes and come though the glass. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArcadeHacker Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 2018 at 4:57pm
As promised I tested if any of my CRTs leak xrays, here's the findings:

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Flinnster Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 2018 at 6:06pm
Loving the science in all this.
So from your findings, a Nanao MS9 on the Astro is actually sucking in background radiation?
Good news for all in Cornwall then Wink

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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArcadeHacker Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 2018 at 6:46pm
Sensors are significantly affected by temperature, those variations are most likely that.
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