power supply for crt

Discussion in 'General Electronics Chat' started by uv147, Dec 24, 2015.

  1. uv147

    Thread Starter New Member

    Dec 24, 2015
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    hi
    i am quite new to the topic and this is my first project
    i want to buy a crt from a tektronix oscilloscope, and it's service manual says the the cathode needs a -1900V supply and the anode uses another 14kV, and i also know there is a heater but nothing is stated about it in the manual,
    i need the crt to operate without the rest of the oscilloscope and, but i only need the electron beam to be formed, i don't need the deflection plated as i intend to deflect the beam using an external magnetic field.
    does anybody know how can i generate the required voltage?
    thank you very much
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I would have thought it would be easier to look for 'scope with inputs to the X & Y plates as some older ones do for for displaying Lisajous figures etc..
    Another alternative is find an old small monochrome monitor and take the deflection coils off the neck of the CRT.
    Max.
     
  3. uv147

    Thread Starter New Member

    Dec 24, 2015
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    The point of this project is to use magnetic field to deflect the beam,
    i tried looking for monochrome monitor but they cost too much
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    At one time you could not give Monochrome crt monitors away, they were ending up in the dump or re-cyclers.!.;)
    Max.
     
  5. withoutego

    New Member

    Dec 22, 2015
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    Find one of those old portable TVs where everything but the CRT is solid state. The electronics bin at the dump, attics, barns. It gives you the HV and magnetic deflection coils. You can run your own current source into the pair of coils .... or have fun with permanent magnets. IAW, Get something where all the work of putting a spot electron beam on the phosphor is already taken care of. But those old sets are getting scarce.
     
  6. Lestraveled

    Well-Known Member

    May 19, 2014
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    I say buy a Tektronix model 535 that still works and remove the CRT and the power supply. Two birds, one stone.

    [​IMG]
     
  7. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    This is way, way beyond a first project. Believe me when I tell you that you want to be awfully careful around HV supplies for CRTs. I used to repair televisions back in high school. I learned that lesson one time and it was all that I needed for it to sink in.
     
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  8. crutschow

    Expert

    Mar 14, 2008
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    Yes, getting zapped by a few thousand volts does tend to stay in one's memory. ;)
     
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  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Although being having been around many industrial potentially dangerous procedures and the results of 'Accidents' , it my experience that it is usually the trainee and neophyte that practices extra caution, the long time experienced seem to be come jaded and drop their guard, and these are usually the ones that become harmed.
    Max.
     
  10. sailorjoe

    Member

    Jun 4, 2013
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    But only if you still HAVE a memory afterwards. <grin>
     
  11. SWer

    New Member

    Dec 20, 2015
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  12. withoutego

    New Member

    Dec 22, 2015
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    Yes, treat HV like you would a cobra or table saw, keep your
    attention focused. And I agree, an old O'scope with direct X-Y
    input would do the job without modification and keep the HV
    isolated.

    Everyone wants to be another Tesla, HV is so exciting.
     
  13. #12

    Expert

    Nov 30, 2010
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    Just checking...do you realize that a, "yoke" is a magnetic field generator?
    The yoke is an old word for the coils mounted on the neck of the CRT.
     
  14. ISB123

    Well-Known Member

    May 21, 2014
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    Now you know how PROM feels.:D
     
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  15. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    Now I feel old. Thanks for the Christmas present. :)
     
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  16. DickCappels

    Moderator

    Aug 21, 2008
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    High Voltage Power Supplies
    If you have some money to spend, you can buy laboratory power supplies from those who manufacture them.

    Spellman Hight Voltage Electronics Corporation comes to mind:
    http://www.spellmanhv.com/

    TV Sets/Computer Monitors
    uv147 might not recognize the opportunity
    represented by an old monochrome CRT television or computer monitor chassis. One can remove the deflection coils (yoke) from the CRT and expose the CRT to the magnetic fields you are interested in. In most monitors the deflection yoke must remain in the circuit or appropriate coils substituted because they are necessary for the generation of high voltage and in some cases they affect circuits that wold blank the CRT in the event of circuit failure.

    Old Ball Brothers/Miratel

    Stay away from color tubes -too many beams to worry about plus the internal magnetic shields might interfere with your experiments/observations.

    @#12 The term "yoke" is appropriate since it goes around the CRT's "neck".
     
  17. #12

    Expert

    Nov 30, 2010
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    Eh? Speak up, sonny. My knees are creaking so loudly today that I just got out my old knee pads so I can crawl around in a car and clean the carpeting.:rolleyes:

    :p
     
  18. DickCappels

    Moderator

    Aug 21, 2008
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    10 mg of Piroxicam (Motrin) daily keeps my knees quiet.
     
  19. #12

    Expert

    Nov 30, 2010
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    Better living through chemistry!:p
     
  20. uv147

    Thread Starter New Member

    Dec 24, 2015
    18
    0

    so i can just buy one of the those portable monochrome tvs on ebay, open it up, remove the deflection coils, and use the rest of the tv for my project?
    or are there only specific models in which the coils are removable?
     
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