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Sep 2, 2009. 2:07 AMDjFluorescent
says:
this worked great for me. but then i ended up breaking it doing some experimenting.... oopz.
Sep 2, 2009. 7:49 AMThe 4th Doctor (author)
says:
same thing happened to me but i made another one lulz
Sep 2, 2009. 1:19 PMDjFluorescent
says:
i saw some ppl on you tube that did this with a crt (computer) monitor. i'm going to try that since i have run out of breakable TVs... :)
Sep 2, 2009. 9:06 PMDjFluorescent
says:
it worked with a comp moniter. only you can only get a virtical line.... horizontal didn't work.
Aug 6, 2009. 1:25 PMmark28
says:
i`like to built a osciloscope to prove electronics parts in my car o diferents sensors can i do that with this project?
Aug 1, 2009. 1:00 PMtimbob
says:
Thanks for this instructable! mine basically works now :D. Only, the horizontal line is really short. Is that the part where i have to mess with V-hold or H-hold or something? that part wasn't really clear for me.. Also, i can't seem to find either of those things on the tv.. Could it be on the circuit board somewhere? what do i look for?
Aug 1, 2009. 3:29 PMThe 4th Doctor (author)
says:
that happened with my new one take a look at my new instructable (and vote for it =D) try hooking vertical back up to the vertical coil and put the music into the horizontal coil and tilt your tv to the side.
Jun 22, 2009. 1:07 AMcharlieb000
says:
i disconnected a coil and the beam went off ! i know i need to control both coils so is there a way around that? it is a small 12v TV (B&W)
Jun 22, 2009. 1:45 AMThe 4th Doctor (author)
says:
hmm there may be no way around that try reconnecting the set you cut and see that its still functioning then cut the other set to see if the beam could stay on with the other set cut and you may be able to get it working i finally attempted to make another one of these with a 1994 color tv and it seems that the tv has to be moderately old and must have a knob for v-hold unless you want use the circular format, soon i will get alot more data on what tv's and displays can be used and put it up
Jun 29, 2009. 2:59 AMcharlieb000
says:
hi, i have done a more permanent modification, and i have found: 1: the light turning off when i played with the coil, well it didnt go off it went dim. and when i switch from TV to scope there is a bright stripe before it goes dim, maybe the brightness of the dot is dependant on the draw of the coil... 2:when i said that it lacks resolution, what is really happening is that the electron beam is flashing on and off on mine and now i have put sound into my coil i can see plainly that my waves are dotted.what can i do to the beam to keep it on (and as bright as before) 3: according to wiki, there is lead in the glass to reduce the xrays, more rays in color tvs (higher voltages). cb.
Jun 29, 2009. 9:34 PMThe 4th Doctor (author)
says:
thats odd how much is it dimming and is it just staying dim try H-hold I remember that dimming and brightening the beam also different channels changed it a bit the brightest was channel 1 which this tv had for some reason I think it was for testing or something
Jun 30, 2009. 12:45 AMcharlieb000
says:
i think it has something to do with the lower current draw causing a voltage change because when i have the tuner on a chanel it goes to white noise when i flick the switch to change the coil over. v hold may work too i kno it will go brighter when the beam slows (Another mod).
Jul 30, 2009. 4:15 AMCybot Rules
says:
hmm, if it Dependant on whats being drawn from the circuit could finding the resistance of the coil and putting a resistor of that rating or similar work?
Jul 30, 2009. 7:40 PMcharlieb000
says:
i did a little research on crt screen and there is two anode grids, one for focus one for accelerating. i suspect that the focus is now out so if i add some components in i could refocus it when i change the switch to scope without wasting some power - the beam is a little fat :) however (i think) the wire for accel is connected to the brightness and the other is connected direct to the transformer (no control on trans - its a 12v) so may need break that. also i might have solved the dotted line problem and that is to simply disconnect the signal that is effecting the flow of electrons to the cathode ray - so disconnecting the capacitor should work...
Jun 22, 2009. 3:47 AMcharlieb000
says:
vhold works but the display is dim and lacks "resolution" (voltage rise lines have some grey areas in them) so i cant see high frequencies
Jun 22, 2009. 3:08 AMcharlieb000
says:
i think i made an error (that test was ages back), it works now (maybe you should do it when its off :P) well it appears i have to have a vertical scope as the knob at the back (vhold) appears to altr the flash rate. well if i get it done it makes a good portable :D id still like to use it as tv so i wont grafitti a grid on it
Jul 22, 2009. 11:45 PMNinquetasar
says:
I tried this today, but when I switched it so it was vertical going into horizontal, I got a small vertical line that barely moved to the sound. Any Idea as to what's going on? Also, how do I adjust the V hold and H hold? Thanks!
Jul 23, 2009. 7:33 PMThe 4th Doctor (author)
says:
try hooking the vertical coil back to the vertical drive and use the horizontal as your source i had to do that with my new one i suppose in some tv's theres a difference between the two coils so the vertical drive only works correctly on the vertical coil there should defiantly be a knob on the outside of the tv for v-hold possibly in a hole for a small screwdriver h-hold may be inside of the tv but shouldent need to be adjusted
Jul 23, 2009. 8:54 PMNinquetasar
says:
Thanks! You're actually helpful the other person who posted something similar just wished me luck. I'll try it! If I adjust the v-hold will I get more than the boring stuff?
Jul 2, 2009. 7:11 PMscgtrp
says:
Just did this with an old 5-inch black and white TV my neighbors gave me. Haven't gotten around to hooking up any audio to it yet, but if I play some static from the airwaves, the line does jump a bit, so I assume I did something right. One question though: any idea how to decrease the brightness of the line? When it's not moving at all it's so bright it's almost blinding, and I have the TV's brightness all the way down. I assume it'd be as easy as a couple of resistors in the right places, but I don't know much about CRTs so I wouldn't know where the "right places" would be. Also, I didn't have to tap into the supply lines, all I did was disconnect the two vertical deflection wires from the board and connect them in parallel with the TV's speaker. Unfortunately the amount of vibration in the line varies with the volume now, but I suppose I could just call that a feature. :-) Looking back I wish I'd done the pulsing from the center style instead, but now I'm out of electrical tape. :-( And, uh, on step 2 are you actually suggesting that I stick my hand inside a powered-on TV with a battery?
Jul 3, 2009. 11:04 PMThe 4th Doctor (author)
says:
well its very odd that just adjusting the brightness wont do the trick on the tv i used that would completely darken the screen easily when you look inside the tv do you see any small knobs you can adjust with a screwdriver they should be labled but you could just try random ones you hooked the vertical coil to the sound output to see that it was working? if you left the horizontal coil connected to the horizontal supply you get a solid line that expands and contracts instead of waveforms which i find the least entertaining personally defiantly like the waveform mode the most but the pulsing from the center mode isent to bad and on step 2 i had already extended the wires for the vertical coil to the outside of the tv which i suppose wasent very illustrated
Jul 4, 2009. 9:01 AMscgtrp
says:
The brightness knob (on the back, not inside) is already all the way down.
You may be (probably are) right about the horizontal line thing, I only tested this with TV static (the TV has a builtin radio, but I stupidly forgot that the TV and radio can't run at the same time while I was building this) and it looked like it was trying to make waveforms, but I could be wrong. I found the configurations page a bit confusing, but reading it again I think I see where I went wrong. Thanks for that.
Now I just have to find a spare audio jack, or a RCA audio cable, to hook it up to a real sound source. That, or work out how to make the radio and TV turn on at the same time.
You may be (probably are) right about the horizontal line thing, I only tested this with TV static (the TV has a builtin radio, but I stupidly forgot that the TV and radio can't run at the same time while I was building this) and it looked like it was trying to make waveforms, but I could be wrong. I found the configurations page a bit confusing, but reading it again I think I see where I went wrong. Thanks for that.
Now I just have to find a spare audio jack, or a RCA audio cable, to hook it up to a real sound source. That, or work out how to make the radio and TV turn on at the same time.
Jul 4, 2009. 9:57 AMscgtrp
says:
Awesome, I see some clear waveforms there after wiring it up the other way. Thanks!
Jun 22, 2009. 1:48 AMThe 4th Doctor (author)
says:
at the moment i dont think so im going to do some testing quite soon and see just what will work for this i think whatever you use must have a knob for v-hold but this is quite unverified
Apr 10, 2009. 1:08 PM12V
says:
DANGER do not let the electron beam point off the screen as there is no phosphor to trap x-rays and may damage the tube! try to keep the beam on the phosphors.
Jun 5, 2009. 9:51 PMDerin
says:
i think x-rays form when electrons get stopped on their path.But,the monitor shuts down if it detects X-rays.
Jun 18, 2009. 6:38 PMwelder guy
says:
HOW HOW HOW????!!!!!!!! does it have a hidden geiger counter!!!!!! how does it detect x-rays!!!!!!!! please reply i'm curius and have a love of radiation and electronics!!!!
Apr 11, 2009. 1:07 AMThe 4th Doctor (author)
says:
I was wondering about that said something about it on the last page i have done it but not too much any details on how much of a hazard it is. am i sterile or will i just form mutants
This is a fun project - I made one a few months ago. Can you please include some sort of schematic or other diagram - it would make it much easier.
May 2, 2009. 8:16 PMThe 4th Doctor (author)
says:
ok i put something up on the 3rd page is that helpful?
I never actually used these instructions, I found them elsewhere. I like how you tried to make a good picture of it all, but it is a bit too confusing. Try using some sort of circuit drawing software.
Apr 11, 2009. 3:43 PMnickk
says:
interesting project but your pics are so blured we can't see anything, maybe u can include some drawing explaining how to connect the horizontal and vertical cables and with what exactly.
Apr 11, 2009. 10:57 PMThe 4th Doctor (author)
says:
yeah never notice how blurry the pics of the wires are when i make another one of these ill take some better pics what about my writing it seems like i go threw some parts too fast to me
To the more passive-electronics-savvy: could you feasibly put together some sort of LRC circuit that would shift the phase of the sound signal, use that to drive one coil and the plain signal to drive the other to get some sort of lissajous-style squiggles? Actually I don't see why connecting the signal to the X and Y coils gives a circle- wouldn't it just be a diagonal line? Or do the coils already have lag because of different inductances or something?
Mar 4, 2009. 7:49 PMThe 4th Doctor (author)
says:
as for the LRC circuit., me personally no but im sure its possible. Ive got no idea how you could shift the phase it could be difficult to do especially with music because it verys so much And I suppose you would just get a dot in one of the corners (depending on polarity) with DC into both coils i never did that for some reason but when its music or a frequency its oscillating and brings the electron beam all the way around And when i put a sine wave into both coils it actually gives me an oblong circle since the coils are both oscillating in the same way i suppose
I was thinking of doing exactly this myself, so I appreciate seeing it! L
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