1. Forum
  2. USENET
  3. comp.sys.cbm

  • Re: PET 3032 keyboard problem - is this fixable?

    From GR@gareth_randall@hot_hatespam_mail.com to comp.sys.cbm on Monday, July 14, 2003 09:36:23
    From Newsgroup: comp.sys.cbm

    If none of the key work or noticible patterns of keys dont work it is most >likely I/O chip

    I have found that if I push *very* hard on the contacts - *much*
    harder than you can push by pressing a key on the keyboard - the
    computer registers the appropriate keypress.

    Presumably, if the I/O chip was faulty, the keys simply wouldn't work
    at all, no matter how hard I pushed the contact?

    --- Synchronet 3.18b-Win32 NewsLink 1.113
  • From Peter van Merkerk@merkerk@deadspam.com to comp.sys.cbm on Monday, July 14, 2003 13:47:04
    From Newsgroup: comp.sys.cbm

    I have found that if I push *very* hard on the contacts - *much*
    harder than you can push by pressing a key on the keyboard - the
    computer registers the appropriate keypress.

    Presumably, if the I/O chip was faulty, the keys simply wouldn't work
    at all, no matter how hard I pushed the contact?

    Correct.

    --
    Peter van Merkerk
    peter.van.merkerk(at)dse.nl


    --- Synchronet 3.18b-Win32 NewsLink 1.113
  • From Nicolas Welte@welte_spam@freenet.de to comp.sys.cbm on Monday, July 14, 2003 16:57:55
    From Newsgroup: comp.sys.cbm

    GR wrote:

    If none of the key work or noticible patterns of keys dont work it is most >>likely I/O chip


    I have found that if I push *very* hard on the contacts - *much*
    harder than you can push by pressing a key on the keyboard - the
    computer registers the appropriate keypress.

    Presumably, if the I/O chip was faulty, the keys simply wouldn't work
    at all, no matter how hard I pushed the contact?

    Yes.

    I had some success to improve my PET keyboards response by cleaning the gold contacts with a cleaner made to remove oxides from printed circuit boards. I noticed that the gold layer was not as shiny as on other keyboards, but even after cleaning it did not look better. It seems the gold layer is much
    thinner than on later keyboards. (Maybe first removing the oxide and then replating the gold layer would be better).

    The other part of the contact can also be improved. There are special repair paints for the conductive rubber keys used in remote controls and
    calculators. Should work fine on PET keyboards, too, but I never tried it. That paint is expensive, and I have no idea how long it lasts.

    I could look up the order numbers of the two items, but both are from German suppliers, so they probably won't help you much. But maybe you can find similar items in your country.

    Nicolas

    --
    Email address is valid for replies (requires Re: in the subject) <--
    - See my Commodore hardware projects at http://people.freenet.de/x1541 -
    - Visit the German X1541 Shop at http://sta.c64.org/x1541shop_ger.html -

    --- Synchronet 3.18b-Win32 NewsLink 1.113
  • From GR@gareth_randall@hot_hatespam_mail.com to comp.sys.cbm on Sunday, July 06, 2003 17:04:04
    From Newsgroup: comp.sys.cbm

    I've just been cleaning my PET keyboard to try and get it working
    again - currently, none of the keys work.

    I did all the usual cleaning tricks (it wasn't very dirty at all), put
    it all back together - still nothing.

    So I opened it all up again, removed the rubber contact from the
    underside of one of the keys and pushed it VERY hard against a gold
    contact on the PCB - and it registered a correct keypress.

    Could it be that the problem is with the rubber contacts, and they've
    worn down so much that the normal key travel isn't enough to make
    proper contact? Or do I need to clean the gold contacts on the PCB
    until they're all as shiny as possible? As I said, they're not
    particularly dirty as it is - the centre of each contact is just a bit
    less shiny than the outer part.

    And if it *is* the rubber contacts, is there any hope of a repair? I'm
    guessing you haven't been able to buy replacement contacts for about
    20+ years...

    Any help gratefully appreciated!

    Cheers,

    Gareth
    --- Synchronet 3.18b-Win32 NewsLink 1.113
  • From Paul Foerster@paul.foerster@gmx.net to comp.sys.cbm on Sunday, July 06, 2003 19:18:06
    From Newsgroup: comp.sys.cbm

    Hi Gareth

    As I said, they're not particularly dirty as it is - the centre of
    each contact is just a bit less shiny than the outer part.

    ... there are no replacements for the rubber pads that I know of. AFAIR
    these pads should have a resistance of 70 to 100 Ohm or so. As for the contacts: Make sure they look shiny as when they were new. Even a very
    thin film of dirt can make contacts impossible.
    --
    cul8er,

    Paul
    paul.foerster@gmx.net

    --- Synchronet 3.18b-Win32 NewsLink 1.113
  • From Circus@circus-spam@hotmail.com to comp.sys.cbm on Friday, July 11, 2003 10:45:57
    From Newsgroup: comp.sys.cbm

    If none of the key work or noticible patterns of keys dont work it is most likely I/O chip the keyboard plugs into, proably a 6522 or 6532? It should
    be east to figure out wich chip because the keybord plug on the 8032 motherboard will go straight or almost straight to it.

    Circus

    "Paul Foerster" <paul.foerster@gmx.net> wrote in message news:be9lkb$2kdd7$1@ID-3726.news.dfncis.de...
    Hi Gareth

    As I said, they're not particularly dirty as it is - the centre of
    each contact is just a bit less shiny than the outer part.

    ... there are no replacements for the rubber pads that I know of. AFAIR
    these pads should have a resistance of 70 to 100 Ohm or so. As for the contacts: Make sure they look shiny as when they were new. Even a very
    thin film of dirt can make contacts impossible.
    --
    cul8er,

    Paul
    paul.foerster@gmx.net



    --- Synchronet 3.18b-Win32 NewsLink 1.113