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Thread: Pericom terminal restoration

  1. #1
    Join Date
    Nov 2017
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    Default Pericom terminal restoration

    So I bought this non working Pericom terminal which won't power up (shorted smoothing capacitors and burned out bridge rectifier) and also has a pretty 'terminal' case of screen 'cataracts'.

    Have the rectifier and capacitors on order so decided to tackle the screen problem. This is caused by the ageing of the 'glue' that bonds a layer of protective glass to the CRT. It becomes opaque and starts to bubble - usually around the edges.

    IMG_20190601_104748413.jpg

    I have safety goggles and gloves for the job - I don't want the tube shattering and blowing glass to my face or to burn myself on the hot tube.
    The tube had been sitting outside on a hot sunny day and was already hot to touch after an hour.
    After scraping the exposed glue from the outer edge the heat gun was applied working around the edges towards the centre.

    IMG_20190601_104744128.jpg

    As the glue melts, I start to slide in wedges between the glass layers.
    You can see the pattern of glue melting and lifting towards the centre of the CRT.

    IMG_20190601_111043115.jpg

    Eventually it lifts off quite easily leaving behind quite a thick layer of rubbery glue residue that easily scrapes off the tube.

    IMG_20190601_111220021.jpg

    Its all done quite quickly < 30 minutes in my case.

    But I then spent another hour cleaning off the residue from both the CRT and the glass protection layer.

    Looks like new when finished and the protector put back in place.

    IMG_20190601_120154020.jpg

    IMG_20190601_120225224.jpg
    Last edited by zippysticks; June 1st, 2019 at 04:30 AM.

  2. #2

    Default

    I did this with a strange 1970’s wide CRT on an HP terminal. I used a long nichrome wire with wooden dowel handles and 12v from an old PC-AT power supply to cut/burn through the material. I believe that it was “optical grade” RTV, and that the cataract is some kind of mold. This job scared me so much that I built a plywood box/stand to hold/protect the tube.

  3. #3
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    Default

    This tube was held in a bucket wrapped in a towel.
    I had a full face protection mask on just in case the tube went - not as scary to me as discharging the tube. Although quite safe to discharge if done properly its always the anticipation of the spark and the need to check it at least five times if it doesn't spark at all.

  4. #4
    Join Date
    Sep 2006
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    Silicon Valley
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    Default

    Quote Originally Posted by Slob View Post
    I believe that the cataract is some kind of mold.
    It is not mold.

  5. #5
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    Default

    Nice job - well done!
    Torfinn

  6. #6
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    It's been a while.

    Replaced all the filter capacitors and several tantalum capacitors in the power supply and this terminal is now working.

    It's really rather nice.


    IMG_20191005_170508772.jpg

  7. #7
    Join Date
    Mar 2006
    Location
    Salt Lake City, UT, USA
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    368

    Default

    There's not much out there about Pericom terminals. Is yours the MX-4000?

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