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rebuilding a computer keyboard

Discussion in 'Electronic Repair' started by Reid Priedhorsky, Jun 8, 2007.

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  1. Hi folks,

    I have a keyboard which I love, and which is beginning to wear out. (It's
    a DataDesk SmartBoard.) I am trying to get a hold of a replacement, but
    the company has been apparently imploding for years -- none of the linked
    distributors have it (except perhaps a company in Canada), the web
    ordering system has been "under construction" since 2001 -- and now phone
    calls are unanswered, with a message saying "... until May 1, we are
    relocating...".

    Anyway, I can't imagine going back to a different keyboard, so I wonder if
    it would be possible to rebuild the one I've got. The symptoms are that
    various keys are no longer reliable, giving zero or many logical
    keypresses for one physical keypress. Different keys are differently
    reliable. Some keys feel a little wonky too, esp. the spacebar.

    I was thinking I might disassemble it, desolder all the keyswitches, and
    replace them with new ones. Is this feasible? If so, is there a better
    source for keyswitches other than another keyboard? Or is there a better
    strategy?

    I'm no electronics expert, but I've managed to successfully build a couple
    of simple battery-powered switching power supplies, including soldering an
    SOIC-package IC.

    Please let me know what questions you have or what additional information
    would be helpful.

    (Alternately, a reliable source to buy one of these suckers would be very
    helpful!)

    Thanks in advance,

    Reid
     
  2. Meat Plow

    Meat Plow Guest

    Typically the switches in a keyboard are a rubber dome (for lack of a
    better word) on the bottom of the key with a conductive pad in the middle
    and a contact area on a pc board for all the keys. Unless you have
    something very unique there are no replaceable switches.
     
  3. N Cook

    N Cook Guest

    Have the keys failed roughly in order of letter/function frequency or did a
    number of them fail about the same time ?
    If discrete keyswitches then you could swap good, rarely used, for bad.
    Anyone ever spilt liquid , even sweat of the brow down under the keys?
     
  4. jakdedert

    jakdedert Guest

    Others might give you better detail on repairing the keyboard; but I'd
    suggest eBay as a source for a replacement....

    jak
     
  5. Rubber dome or other capacitive sensor on modern keyboards with no tactile
    feel. :)

    Actual mechanical switches on my favorite Northgate and clone KBs.

    In the latter case, the individual switches can be unsoldered, popped out,
    and replaced easily. In many cases, they can even be disassembled and
    cleaned.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  6. Marra

    Marra Guest

    You can buy a new keyboard for a few pounds !
    Why are you messing around with this ancient one?
     
  7. Perhaps if you ever had used a KB with good tactile feedback you would
    not be so quick to throw it away.

    I have a pile of modern KBs I'd happily give away.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  8. Meat Plow

    Meat Plow Guest

    Yes I suppose the kind that have the little metal plate on top do indeed
    solder to the board. Where do you get replacements? How good are your eyes?
    Only keyboard I ever fixed was one of those Dvorak jobs for a gal at a non
    profit org that I used to do some work for.
     
  9. jakdedert

    jakdedert Guest

    Hear, hear! I'm a big fan of the old AT style 'clickity-clacks'. I dig
    through every pile of thrift store keyboards, yard sales etc; to pick up
    every one I can find. So far, I've not been 'without', but I dread the
    day when I have to shell out for a new one (I understand they're still
    available).

    I happily eschew the modern special-key functionality available
    (including the now-standard 'Windows' key) in return for a keyboard
    which *feels* like a keyboard.

    jak
     
  10. mc

    mc Guest

  11. Actually, there are two through-hole pins on each switch, which then simply
    pop out. I usually just take switches from locations that are rarely used
    like F12 :), or my parts KB.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  12. Meat Plow

    Meat Plow Guest

    Makes sense until you need F12 :p
     
  13. Usually, they are flakey, not totally dead. So, maybe a bit of a
    stutter. :)

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  14. neon

    neon

    1,325
    0
    Oct 21, 2006
    i did not read all of the advices but new keyboard are not mechanical switches and are not repairable. some company actualy give them away free as rebates. if your keyboard is realy old then you need cleaning. there are cleaners that you can spray to clean contacts but spraying only moves dirt from here to there immersion is the way. good luck
     
  15. The keyswitches are small black cubes around 1/2" on a side, with a little
    plunger on top that the key cap fits onto.

    They can indeed be disassembled and cleaned, but there's a number of very
    tiny parts inside, including a very tiny coil spring, and it's extremely
    difficult to put them back together. (No sign of any rubber domes.) So, I
    think replacement is the only reasonable option.

    It sounds like the strategy is to find one or a few garage sale keyboards
    that seem to have the right kind of switch, and scavenge keyswitches from
    them.

    Question: Are all the switches in a keyboard uniform? In other words,
    should I use a rarely-used keyswitch from the donor keyboard for
    heavily-used keys like Backspace, because they'll be less worn, or should
    I use e.g. the Backspace key from the donor keyboard for Backspace,
    because it's a tougher keyswitch?

    Thanks again,

    Reid
     
  16. Without attempting to sound snarky... in this case, you get what you pay
    for. :)

    This keyboard costs over $100 (£50), and it's worth every penny. Nice
    tactile feel aside, what is really great is the arrangement of keys:
    instead of the rows being staggered, they form a grid -- i.e., the keys
    are where your fingers want to go, not 1/4" off to the side.

    Photos: http://www.datadesktech.com/media_photo_base.html

    Take care,

    Reid
     
  17. In the KBs I'm referring to, the switches are all the same, but some of
    the sttictly mechanical stuff for the spacebar and return keys differ.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  18. Franc Zabkar

    Franc Zabkar Guest

    Be aware that the presence of tactile feedback doesn't necessary imply
    that the key switches are "mechanical". You could still have a
    "membrane" keyboard with a "buckling spring" mechanism to provide the
    "clicky" feel.

    See http://park16.wakwak.com/~ex4/kb/tech_bucklingspring_e.htm

    "IBM 5576-A01,003 and Enhanced 101 model M generate clicking sounds
    when we type. These keyboards actually use 'Membrane switches'. But it
    seems that many people misunderstand that these keyboards use
    so-called 'Mechanical switches', so I decided to let people know the
    truth about 'buckling keyboards'".

    - Franc Zabkar
     
  19. Franc Zabkar

    Franc Zabkar Guest

    Why not use a key which is essentially duplicated, such as one of the
    keys in the numeric keypad?

    - Franc Zabkar
     
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