=<>=<>=››               KEYBOARD FIX›› This article has been taken from Z*MAG› Atari on-line newsletter. It is a good› article   on  fixing  keyboards,  even› though it can't  solve  all  problems.› File    was    transferred   by   Mike› Blenkiron,   and   tidied   by    Dean› Garraghty  and  reprinted  by  THE OL'› HACKERS, A.U.G., Inc.››           ----------------------›› This   is  probably  one  of  my  last› original articles from me for a while,› but  I  will  try to bring you some of› the  best  fixes,  modifications,  and› other projects of other authors in the› coming  months.    In   this   article› however,  I  will try to give a little› help on fixing one of the more  common› breakdowns,  the  keyboard.   I'm sure› quite a few of you have an   Atari  in› the  closet  with  a keyboard that has› gone belly-up in one way or  another. › You  would like to put that machine to› use again, or would like  to  sell  it› for  the  best  price  as  a   working› computer, so let's dig right in.›› The 400's membrane keyboard was a joke› from the git-go.   The  only  solution› there  is  replacement,  and  a lot of› people replaced them with  third party› keyboards.   Since  there were so many› manufacturers, I can't even  begin  to› cover them all here.›› With  the 800's, as well as the 800XL,› there were more  than  one  design  of› keyboards,  by far the most durable of› which was the  full  stroke,  contact-› switch type.  Stackpole was one of the› major manufacturers  here.  While  I'm› not  sure  about  what  percentage  of› 800's  used this type, not many of the› 800XL's   had  them.   If  you  should› happen to have an 800 or 800XL with  a› Stackpole  keyboard,  then  you should› have very little if any problems  with› it.   If  you  lose  function of a key› here, a nice bath with  a  good  tuner› cleaner  will  take  care  of even the› nastiest keys.  If that doesn't  work,› then the keyswitch can be replaced.›› The  other  was  the  printed  circuit› contact  sheet, where conductive paint› traces were silkscreened onto  plastic› sheets.   My  800  is  one  of  these,› manufactured  by Mitsumi, and a lot of› the 800XL's were made by Chelco.  Here› you  must  exercise  a   little   more› caution.   DO NOT use any solvent type› cleaner or you will  wash  the  traces› right off.  The only thing you can use› here is a  little  water  and  a  soft› cloth.  Even alcohol will discolor the› traces and raise the resistance.  If a› trace  is  broken,  a  little  dab  of› conductive  paint,  available  at  any› electronic  supply  store, will fix it› up nicely.  If the key  still  doesn't› work,  try  giving  the  spring   that› presses  against that contact a little› stretch.  Be careful here,  as  it  is› easy  to  go  too far and have the key› stick on all the time. Remember, it is› easier  to stretch a spring than it is› to shorten it, (cutting it is "NOT" an› acceptable  alternative!!).   If   the› problem  is  a key sticking on all the› time, try it with the pressure  spring› removed.   If it stops repeating, then› shorten   the   pressure   spring   by› squeezing    it   down   with   gentle› pressure.  If it  still  sticks,  then› take the separator sheet (the one with› all the holes in it), and add a  piece› of  scotch tape over the corresponding› hole, and cut out the  tape  where  it› covers  the  hole.   Don't use masking› tape or anything like that, as  it  is› too  thick.  You should never use more› than two layers  of  scotch  tape  for› this  type  of  repair.   If  it still› sticks after  two,  then  replace  the› keyboard  or  use  the  computer   for› parts.   There are quite a few 800XL's› floating around that can be had for  a› more-than-reasonable  price,  and  you› should  be  able  to  find  one with a› working keyboard.›› The 130XE was a radical departure from› the  others,  in  that it used only a › single   sheet   of  plastic,  with  a› contact on the bottom of the keyshafts› bridging  two  contacts on the sheet. › Here if cleaning  doesn't  help,  save› yourself  a  lot  of  aggravation  and› replace the keyboard.›› If  you've found everything to be fine› and dandy with  the  keyboard  itself,› but you don't have function of a group› of keys, check  the  ribbon  connector› where  the  keyboard  connects  to the› computer.    There   may   be   a  bad› connection.  On the 800 this shouldn't› happen,  as  this  is  a full plastic-› bodied   18-pin   connector.   On  the› 800XL,   the   ribbon   is  merely  an› extension of the  silk-screened  sheet› that  slips  into  a  connector on the› main board. If part of the  conductive› paint  has been scrapped away, you can› reach fresh trace by trimming down the› ribbon a little.  If you find yourself› having to go too far, then replace the› keyboard.›› Sometimes  the  problem is on the main› board itself.  The keyboard is read by› two  4051  decoders  and  fed into the› POKEY  chip.   Try  swapping  out  the› chips, one at a time,  and  eventually› the keyboard should come back to life. › If not, then there is a  more  serious› problem  that  requires   professional› attention.›› Hopefully,  I  have  given  you enough› information here to enable you  to  do› some  of your own keyboard repairs and› save a little money.››                *=end=*›