Toughbook CF-30 CCFL Backlight Failure

Discussion in 'Panasonic' started by Mark Wickens, Sep 20, 2016.

  1. Mark Wickens

    Mark Wickens Notebook Enthusiast

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    Would I need to be ordering 4 tubes in total?
     
  2. Shawn

    Shawn Crackpot Search Ninja and Options Whore

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    No just 2 tubes per lcd panel.

    I would recommend picking up a used lcd panel and swap the panels.
    This gets your CF 30 up and running and allows you take your time to swap out the tubes on your panel. Then you can swap in your rebuilt panel once it is done.
     
  3. CWB32

    CWB32 Need parts for my flying saucer.

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    the electrolytic caps like to "fade away" simply because of age and is the nature of the beast .
    the "beast" is filtering/decoupling (aka : provide a low impedance path) the garbage and hash from the switchmode supply ... this is hard on electrolytics .
    there are various grades of electrolytics ...
    currently (i'll take the pun) there are two major families : 85C and 105C .
    the 105C types are designed for more abusive *environments* (physical and electrical)
    the 85C types are used in more "relaxed" situations (think : inside a stereo , tape deck , etc .)
    a switchmode supply will beat the snot out of a 85C electrolytic by virtue of hitting it with square waves (well , pretty much square waves) ... so much so that they will fail (catastrophically at times) in short order .
    just ask anyone who has replaced a 105C cap with a "plain jane" ... when timed juuust right it is a good trick for new year eve at midnight .
    (yours truly has had a fair sized one grenade about a foot from his face)
    in power supplies , when used as a coupler or filter there is an appreciable amount of current required from them ... this requires robust internal construction as well as low inductance and low ESR (equivalent series resistance) .
    back in my formative years (read *girl chasing*) ESR was known as "power factor" ... a little google-foo will expand these two items and hopefully allow more sense to be made from my ramblings .
    while switchmode supplies are much more efficient than their linear/shunt regulator brethren ... they are a different breed of cat and require more appreciation of what a square wave is , the effect with inductance and a few other things that one does not normally consider in fine detail with 50/60Hz AC or DC circuitry .

    just like other electronic components , there are *cheapo* and *good* types ... panasonic and nichicon are two good types .
    taking the lcd apart is a bit time consuming and keeping things clean is of great importance ... you will see every speck of dust that you miss .

    as shawn mentioned , there are two lamps used in the '30 lcd ... if you can thread a needle , this should present no real issues .
    don't forget to keep track of those "spacer rings" ... they are almost invisible and will get stirred into the surroundings quickly .
     
    Last edited: Sep 26, 2016
  4. Mark Wickens

    Mark Wickens Notebook Enthusiast

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    Greetings from the Lake District, NW England!

    Not been on here for ages but I can report that after over two years of sitting in bits I finally managed to muster the courage to replace the LCD panel backlight tubes on my CF-30 with ones that I had bought from a company in Poland.

    It was an awful job and it didn't help that somehow I decided to do it with a hangover :( I did manage to put a scratch on the LCD itself (errant screw) and it took forever to convince myself that the bottom of the panel housing which is like a sprung clip was in the correct place (actually, I'm still not convinced, but it isn't coming out again!)

    However... having said all that it did go back together and does work and I've been using it out in the field again which is great. Still have a lot of affection for it! I do amateur radio and it is great for digital modes such as FT8.
    Bizarrely after two years the battery was still at full charge and apart from a slew of Windows 10 updates it works a charm with both Win10 and Ubuntu.

    So just to say thank you for those who offered advice last time I asked.

    Regards, Mark. M0NOM
     
    Last edited by a moderator: Sep 1, 2019
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  5. Shawn

    Shawn Crackpot Search Ninja and Options Whore

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    thanks for the update and success story.
     
  6. toughasnails

    toughasnails Toughbook Moderator Moderator

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    I just reopened the original thread and moved your new thread to it. Thanks for the update.
     
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