With the keyboard taken apart and connected to the computer, use a screwdriver to short the contacts for a key. Even with bad contacts, you should get a response. If you get no response, then you have a break in the keyboard circuit, or a bad interface chip. If you do get a response, then the rubber contact on the bottom of the key may need cleaning. Sometimes this contact shrinks with age. In this case, when you press the key, it may not go down far enough to make contact. This can usuallly be fixed by putting something the rubber contact and the plastic part of the key. On Wed, 9 Sep 2015, Terry Raymond wrote: > Well even pressing on the key hard wont work so theres some wear somewhere. > > I really used this Vic a lot and typed in a lot of programs etc back in the > early 1990's > so it had lots of use. > > Terry Raymond > > On Wednesday, September 9, 2015, William Levak <wlevak@sdf.org> wrote: > >> >> Do you see actual signs of wear? Sometimes corrosion on the surface >> prevents a good contact. Before applying anything to the contacts, try >> cleaning them with a non-abrasive pencil eraser. If that does not work, try >> lightly polishing them with 1500 grit sandpaper. >> >> >> On Tue, 8 Sep 2015, Terry Raymond wrote: >> >> I think my two keyboards the contacts on the KB PCB are worn I heard years >>> ago there is a compound that can be applied to the contact to build it up >>> to repair it. >>> Terry Raymond >>> >>> On Monday, September 7, 2015, Gerrit Heitsch <gerrit@laosinh.s.bawue.de> >>> wrote: >>> >>> On 09/07/2015 06:29 PM, William Levak wrote: >>>> >>>> On Mon, 7 Sep 2015, Giacomo wrote: >>>>> >>>>> Or take some time to clean it: >>>>> >>>>>> http://www.oldcomputr.com/cleaning-the-keyboard-of-a-vic-20/ >>>>>> You have to desolder the shift lock contacts under the keyboard, then >>>>>> it's >>>>>> just a matter of unscrewing a couple of dozen of small screws. Remove >>>>>> all >>>>>> the dirt then gently clean the contacts with isopropyl alcohol. >>>>>> >>>>>> >>>>> >>>>> 91 per cent isopropyl is preferable, since it takes the water with it >>>>> when it evaporates. >>>>> >>>>> >>>> Be careful if you find you have one of those keyboards that have the >>>> black >>>> coating on the contacts on the PCB. It's a bad idea to remove that >>>> coating. >>>> >>>> Gerrit >>>> >>>> >>>> >>>> Message was sent through the cbm-hackers mailing list >>>> >>>> >>> >>> -- >>> Sent from Gmail Mobile >>> >>> >> wlevak@sdf.lonestar.org >> SDF Public Access UNIX System - http://sdf.lonestar.org >> >> Message was sent through the cbm-hackers mailing list >> > > > -- > Sent from Gmail Mobile > wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2015-09-15 04:00:07
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