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Thread: crt rejuvenation.

  1. #1
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    Default crt rejuvenation.

    Its been a long time since I done this, years, many years.
    Does anyone have any good links or info on rejuvenating a old CRT monitors. I have a few that need it.

    Thanks.
    I have dyslexia, I have alot of trouble putting my thoughts into words and spelling/grammar is something I struggle with.
    You may need to read my posts twice to understand what I said.

  2. #2
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    I do believe I have been told that by the 80's, single gun CRT's and their cathode chemistry were not really the type that respond well to rejuvinations compared to the older designs. People have mentioned about doing it before on Trinitrons and NeXT mono monitors found either it didn't do anything or the rejuvination was relatively short lived.
    Really I had a tube I didn't really care for and a rejuvinator that can handle lower voltage heaters (like the 2.6v philco tubes) I'd be willing to give it a try but you would need the spec for the tube, because once that heater pops, that's all folks.
    = Excellent space heater

  3. #3

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    Typically you crank the voltage up on to filament to about 2X to 2.5X and put a high negative voltage on the girds relative to the cathode. You let that cook for some time. If the filament burns out, no loss as it was bad anyway. If you do it too long, it can boil off too much of the filaments coating, also a loss.
    Dwight

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    Quote Originally Posted by Dwight Elvey View Post
    Typically you crank the voltage up on to filament to about 2X to 2.5X and put a high negative voltage on the girds relative to the cathode. You let that cook for some time. If the filament burns out, no loss as it was bad anyway. If you do it too long, it can boil off too much of the filaments coating, also a loss.
    Dwight
    So what is achieved if this is "successful"?

  5. #5
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    You can (temporarily) boost the emissivity of the cathode. A good indication is to leave the thing powered on for most of a day--if the image brightens a bit at the end, you might do with rejuvenation.

    The other class of rejuvenation is clearing of shorts between elements caused by bits of the cathode flaking off and causing problems. Those can sometimes be cleared by zapping the shorted elements with a charged capacitor.

  6. #6
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  7. #7
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    Oddly, I have a crt rejuvenator - not had cause to use it so far though. About a year ago I was walking past the TV repair shop in Burnley. I saw a 'thing' that caught my eye on a shelf inside. I have an eye for old test equipment. Went inside and had a look - I had seen rejuvenators on youtube so I knew what it was. The guy wanted 20 for it - just getting rid of old test kit, not much use in the LCD era!


    WP_20190329_22_59_56_Pro_LI.jpg

    A bit wasted on me, I have 4 vintage computers, two of which have CRTs one mono and one color!

    WP_20190329_23_06_29_Pro_LI.jpgWP_20190329_23_06_56_Pro_LI.jpg

  8. #8

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    Quote Originally Posted by VERAULT View Post
    So what is achieved if this is "successful"?
    The picture will be brighter if it works.
    Dwight

  9. #9
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    Quote Originally Posted by alan8086 View Post
    Oddly, I have a crt rejuvenator - not had cause to use it so far though. About a year ago I was walking past the TV repair shop in Burnley. I saw a 'thing' that caught my eye on a shelf inside. I have an eye for old test equipment. Went inside and had a look - I had seen rejuvenators on youtube so I knew what it was. The guy wanted 20 for it - just getting rid of old test kit, not much use in the LCD era!


    WP_20190329_22_59_56_Pro_LI.jpg

    A bit wasted on me, I have 4 vintage computers, two of which have CRTs one mono and one color!

    WP_20190329_23_06_29_Pro_LI.jpgWP_20190329_23_06_56_Pro_LI.jpg
    B&K tools are quite well known for their quality. They were about as good as the later electronic Sencore units. They are really nice tools if you regularly work with older TV's.
    = Excellent space heater

  10. #10
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    As a kid I was forever pulling tvs out of skips etc and trying to fix them. I got so I could usually diagnose the issue to a functional location of the chassis if not the actual part. I'd have been blown away to find this rejuvenator back then!

    Quote Originally Posted by NeXT View Post
    B&K tools are quite well known for their quality. They were about as good as the later electronic Sencore units. They are really nice tools if you regularly work with older TV's.

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