Hello i have a problem with a mod i did to a TV to turn it to an oscillograph, it works but in a couple minutes the screen goes off but the led still is on. Anyone had this problem before? Thanks.
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Iāve modded a TV once to make it into an oscilloscope, but there are various ways to do that. So you need to provide some more info on your approach otherwise there is not much to go on. Is it an analog TV or a flat screen / digital one?
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a CRT TV is old one with tube
you maybe make it with this vid
i did on 2 old crt tv i did as many videos said, except for the amplifier cause i dont have any, but on 1 of the tvs it works good, but the other switches off in a couple minutes, i think im gonna just leave it to recicle components if no one had this problem or knows how to solve itā¦ thanks guys
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One thing I can think of is that the tv switches off because it does not get any signal anymore from its antenna. Some tv-s did that in case someone would fall asleep in front of it.
If that is not if, then you will have to provide us with some more information about the modification you made to the tv. Otherwise it will be difficult to help you.
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Never played with CRTs much, but from memory some have shutdown on fault detection. Possible that your mod is triggering that.
Checked that all the correct grounds are is place? Any suspect caps?
Some photos might help?
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I am currently working on a similar project and facing the same problem. I also used the LMNC video for help. I wonāt control the X and Y coil with jacks but they are connected to the outputs of a Hi-Fi Amp. Looks pretty awesome but the CRT TV is also turining off after 10-20 sec.
@The_Anarchrist could you solve the problem ?
Edit: if the problem is some sort of self-turn-off, is it possible to avoid this somehow ?
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What type and brand of tv is it you are modding? What does the mod entail?
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Iām modding a Philips 28PT4406/01. Basically the CRT is used as an exhibition component. Visitors will be able to touch objects and play music with a Playtron by Playtronica (the so know fruit midi controller). And the CRT should display a ā3Dā waveform. Like in this video:
itās just for looking cool and giving the visitors a feeling of doing something interactive.
As I said the visuals are working and looking good for what they will be used for but the CRT keeps switching off.
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Does it switch off after a set time? Then maybe it āthinksā there is no signal anymore. You could try to feed it an RF signal using an antenna or a VHS-recorder and see what happens.
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the time varies between 10 and 30 secs I guess. I turned it on with the wires in the original place: white noise is showing and the TV is not switching off. So I think it is the āno signalā problem
If you have a signal source such as an antenna or a VCR, or an old home computer, then tune the tv to a valid channel and that might solve the problem.
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Let me get this straight. So without the modification the tv does not switch off, but with the mod, it does?
yes that is correct. I have an old VCR. Will definitely try that tomorrow. Thanks for the help so far !
It appears to me that the mod itself might be causing the tv to be switched off. Can you describe what exactly your mod entails? Do you have a schematic or a picture of a sketch of a schematic you could upload?
The mod is nothing really special. Please excuse the informal schematic. I dont know much about the correct sketching 
basically the two wires of every coil are connected to a speaker outoput of a hifi amp. Thatās it. Mod works and I also can change the size of the waves with the volume knob (like LMNC in his vid)
and that is everything I changed so far at the TVs cabling
In many āoldā transistorized TVs the horizontal deflection coil is part of the switch mode power supply (SMPS). Since you disconnected that, that might cause a problem to the rest of the TVās circutry. Disconnecting the vertical coils most times makes no difference to the rest of the TV. Do you have a spare coil (or a similar one) that you can connect to the tv which can take over the part of the horizontal deflection coil? Just connect that to the tvās pcb and keep its magnetic field away from the tube.
If you donāt have another coil, you might experiment with a mains transformer and use one of its coils. E.g. use the primary one and connect that to the leads the horizontal deflection coils was attached to. Make sure you wrap some isolating tape around the secondary coilās leads. Depending on the mains transformer your mileage may vary.
I already tried various possibilitys of connecting the coils. So I had the vertical coil connected to the pcb and the horizontal one connected to the amp and the other way round. Both variations didnāt fix the problem. The TV keeps switching off. Sorry, I should hav mentioned that in the last reply.