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Any advice on testing/powering a CRT from a TV?

I recently salvaged a three color Cathode Ray Tube unit from a big screen TV  (unknown damage) and I've  never worked with them before. I don't know if there is a best way to test them out or what if any special gadgets I might need to do so. My goal is to re-purpose the unit as lighting for my Halloween display. I'm just interested if they can produce light and if I can control the brightness of the light.

framistan6 years ago
Sounds like you have some "small-ish" picture tubes used in a bigscreen projection tv. The problem is EACH tube must be powered by the 20,000 volt source at the ANODE and the negative coating. THEN you must build a driver to place proper voltages on the filiament and various grids/plates etc. (at the neck of the tube)-- to allow full brightness to pass to the front screen. At this point, if you built ALL THAT, you would only have one bright DOT at the center of the screen. Now you must build a circuit that will drive the 4 YOKE coils. This will scan the bright dot VERTICALLY and HORIZONTALLY so the whole screen lights up brightly. If the tube is OLD, it will likely not be fully bright like a new tv. ONE of the 3 will likely be weak. Each tube only puts out ONE COLOR.... red, blue or green. After you build this monsterous circuit, and place it in an appropriate SAFE ENCLOSURE so nobody gets shocked.... then you will realize you could have just bought 3 standard LIGHT BULBS for 50 cents each and accomplished the same task. The absurdity of this project makes me giggle a little.
lemonie6 years ago
What do you mean by "test"?
You need to plug it back into the PCB it was connected to and feed it a signal.

L
Re-design6 years ago
You'll need a high voltage power supply. Maybe 20 kv or so. And other controlling circuits. You might be able to take them out of the "dead" tv.  See this link for more info.  IT's about building a very small O'scope from a small crt but does provide an example of what it takes to provide some control of a crt.  Though this one is very small and low powered compared to what you are planning.  This link shows building one from an old tv.

You need to understand that the CRT that you have is potentially a very dangerous item.

Be very careful.  CRT's can hold a lethal charge for a long time after they've been turned off.  See this link.

CRT's should not be run exposed.  There are too many points of HV.  So unless you want your Halloween display to become a REAL horror you need to shield ALL of the exposed circuitry.

One more and I'll climb off my soap box.  CRT's contain a huge vacuum and even the later "safety glass" crt's will implode and toss chunks of sharp glass in all directions if hit in the wrong location.

Good luck and keep us informed.  If you decide to try something make and instructable out of it.