Hey /diy/, I've got a caseless 5 inch CRT. Do I need to worry about the tube itself building up a dangerous charge, or is the flyback the only dangerous part?
pic isn't mine
Neither.... i have dismantled tons of crt and nevur got a shocks
>>932046
No, right, but what I want to do is use it.
I know I have to protect the flyback transformer to avoid death/housefires. But what about the rest?
Whatever charge there is/was in the tube, it came when the thing was powered up last time. Short the graphite coating to the anode contact if you're worried.
>>932141
I see no problem, It's just like handling one of those +220 V capacitors, nothing to worry about.
>>932141
what's wrong with that? i used to adjust the picture with the case off and unit on.
>>932043
The CRT itself does not hold a charge, the flyback's internal capacitor does. The only way you'll manage a housefire with that would be to have a spark gap between the primary and ground of the flyback looped directly on each side of something flammable, ie, you want it to light something on fire. If you use it like it's supposed to be, everything will be fine. If you want to touch it but you're not sure if it's safe, use one hand only.
>>932161
>The CRT itself does not hold a charge
Yes it does, the aquadag coating forms a capacitor with the glass as the insulator.
>>932161
ty anon
>>932523
No, don't thank him, he's wrong, and you're a fucking idiot for coming to 4CHAN of all fucking places, instead of running a damn google search. I should have let you cop a few kilovolts off the tube as a lesson, but I'm not a cunt like >>932161 is.
https://www.youtube.com/watch?v=-jbnFuVWTdk
The internet. Use it faggot.
>>932525
This is a video of a man reaching under the anode cap while running the CRT though. Do you actually know what you're talking about?
>>932527
Nah, he's charging it up, switching it off, sparking it, then charging it up again.
The electrons fly from the gun to the screen because of the potential difference; they couldn't do that if the screen wasn't a capacitor.
That said, it is just static. It's more dangerous than a fieldmouse, but less dangerous than a chainsaw.
>>932527
OP's question.
>Do I need to worry about the tube itself building up a dangerous charge, or is the flyback the only dangerous part?
This >>932161 faggots response.
> The CRT itself does not hold a charge
This >>932525 guys response.
> The CRT does in fact hold a charge, here's a video of how to discharge it.
You are an illiterate faggot who cannot follow a conversation, and does not know enough about electronics to recognise what this video demonstrates. Please leave this board and never return.
>>932531
OP here
Is the charge built up by the tube dangerous to me if I don't reach under the anode cap?
thanks for all the help btw guys, /g/ was useless.
>>932537
It shouldn't be. The anode cap and its connection back to the flyback transformer are well insulated, so there is very little risk of copping a shock through the cap or the flyback insulation. Personally, unless I need to pull the circuit board out of the unit for bench testing (reads; need to disconnect the anode cap) I won't bother discharging the tube. The danger is always in the back of my mind, complacency can be a killer, but yeah, it's not something you need to do everytime you want to do work.
If you are in any way concerned, the discharge video >>932525 posted is a quick and easy way to give yourself piece of mind. I would also recommend you go have a read up on how the high voltage section of a TV works, and the role aquadag plays in CRT voltage management. Arm yourself with the knowledge to work safely and confidently around HV devices like these, You'll get more done and more importantly, you won't get fucked over because some psychopathic fleshwaste on 4chan thinks it's fun to kill by proxy.
To be clear, you're looking to run this CRT without an enclosure (or maybe put it in your own custom enclosure), correct?
>>932554
>To be clear, you're looking to run this CRT without an enclosure (or maybe put it in your own custom enclosure), correct?
Yes, that's right. I was expecting to have to put the flyback transformer in some sort of enclosure, but the tube itself I'd like to leave exposed.
I'm reading about aquadag now, thanks for pointing me.
>>932537
Am I right in saying that if it's not connected to anything, and it builds up a charge (which it can do), there's no reason to expect the exposed grounding posts should be at ground potential?
Whenever I've had to store these things, I've fashioned an anode-cap clip out of a bulldog clip handle and a wire, and used that to short it to the grounding posts.
I own a Vectrex and these use a similar part.
The tube ITSELF is a big capacitor, charged by the flyback transformer and can hold around 10kV
>>932646
>The tube ITSELF is a big capacitor
Right, but the outside of it is only one terminal, right? You can only shock yourself by touching the flyback at the same time, or by reaching under the anode cap.
Correct?
>>934137
The graphite-coated outside is the other terminal.
>>934138
The graphite coated outside is a terminal. Where is the other?
>>934139
Nah, I just can't read.
The anode contact is the other. So, the tube alone is a capacitor and it doesn't need to be connected to anything else to zap you.
>>934143
Are you sure m8?
>>934153
Yes.
>>934164
That's a video of me touching the tube while the thing is running, please don't shitpost.
Doesn't matter. Remember, amps kill you, not voltage.
>>934345
This post has literally nothing to do with the thread at all.
>>934232
Yeah, the graphite coating alone, which is normally grounded and also the other terminal of the capacitor formed by the CRT. The other terminal is the anode contact.
What's so difficult to understand?
>>934536
Are you ESL? Your sentences literally don't make sense.
>>934536
>Yeah, the graphite coating alone, which is normally grounded and also the other terminal of the capacitor formed by the CRT.
Hiroyuki?
Sweet jesus, someone just tell him how to discharge it instead of debating on if or if not it'll have charge. Ground a long flat screwdriver using wire to something you know is grounded. Use the flat screw driver to to pop off the suction cup of the fly. Touch the opening that the fly attaches to and the metal clips on the fly cup itself. You won't have to worry about anything after that. And YES tubes will collect static over time and recharge. Discharge the tube and fly if you ever worry about shocks. I've known many a tech that have gotten slammed into a wall from bad shock reactions
>>934592
That was a cheap shot, and they absolutely do.
>Yeah, [you were touching] the graphite coating alone, which is normally grounded [;] [the graphite coating is] also the other terminal of the capacitor formed by the CRT.
Personally I'd be a bit wary of doing that, because CRTs often have strange ideas about what potential the chassis should be at, and touching the "ground" on a CRT while it's on can be way more dangerous than getting a boo-boo off the HV, but whatevs.
>>934599
learn to read
>>934606
Pretend I'm trying to kill myself. With one hand on the graphite where to I put my other hand?
Unacceptable answers: flyback, under the anode cap
>>934609
I've got some TVs where (assuming you can't levitate) that one hand would be quite sufficient.
That's why you use an isolation transformer.
>>934617
Please, mate, humor me and answer the question.
>>934621
I wish either one of you would talk to me about the specifics this particular TV. I touch the ADAG no issue- is there another place (ON THE OUTSIDE) I might accidentally touch and die/start a fire?
