discgolfer72 Posted January 2, 2018 Share Posted January 2, 2018 so I have 3 ti-99/4a computers siting here in front of me one beige 2 silver one of the silver ones works great but for some reason keyboard inputs are funky in basic pressing f gives me a capital A pressing r gives me space pressing u is lowercase p a lot of the keys work fine machine launches cart games and plays them fine ( with a joystick) any ideas where should I start also since I'm here the white one just boots to a green screen with beep can use some input on it as well Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted January 2, 2018 Share Posted January 2, 2018 Look at the text on the initial two screens (before you input anything on the keyboard). Is the text sometimes garbled there too? If yes, it may be a bad video RAM chip. If the screens look good, it may be a problem with the keyboard itself (a broken or crossed wire). Quote Link to comment Share on other sites More sharing options...
discgolfer72 Posted January 2, 2018 Author Share Posted January 2, 2018 (edited) nothing out of place that I can notice but I'm new to vintage computers (know arcade and console stuff) https://youtu.be/Mu3eKGbSK3Q Edited January 2, 2018 by discgolfer72 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted January 2, 2018 Share Posted January 2, 2018 Your RAM is good. It looks like the problem is within the keyboard. Were you hitting each key multiple times or was it auto-repeating on you? Also, if you carefully pull one of the key caps off, is there a green box with two sets of metal fingers under it or is there a standard (more modern looking) stalk to plug the key cap into? At this point, it could be translation of the key matrix, bad connections, oxidation, or a broken keyboard wire. Quote Link to comment Share on other sites More sharing options...
discgolfer72 Posted January 2, 2018 Author Share Posted January 2, 2018 (edited) Your RAM is good. It looks like the problem is within the keyboard. Were you hitting each key multiple times or was it auto-repeating on you? Also, if you carefully pull one of the key caps off, is there a green box with two sets of metal fingers under it or is there a standard (more modern looking) stalk to plug the key cap into? At this point, it could be translation of the key matrix, bad connections, oxidation, or a broken keyboard wire. i was pressing several times looks like green stalk with copper contact inside ps thanks Edited January 2, 2018 by discgolfer72 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted January 2, 2018 Share Posted January 2, 2018 That is VERY good. You have one of the better keyboards. On keys that are sticking or not registering, you can clean the copper contacts (carefully). I'd look for a break in the 16-conductor flat cable that connects the keybaord to the motherboard next. . .those get stiff and brittle over time. Quote Link to comment Share on other sites More sharing options...
discgolfer72 Posted January 2, 2018 Author Share Posted January 2, 2018 (edited) That is VERY good. You have one of the better keyboards. On keys that are sticking or not registering, you can clean the copper contacts (carefully). I'd look for a break in the 16-conductor flat cable that connects the keybaord to the motherboard next. . .those get stiff and brittle over time. to late tonight to tear her open guess worst case i swap the motherboard from the silver one with bad kb to the white with bad mb ok got some time swapped the keyboard from the white machine to the one with keyboard problems the problem is still there so its got to be in the motherboard itself im tearing into the white motherboard trying to figure out why its borked right now Edited January 2, 2018 by discgolfer72 1 Quote Link to comment Share on other sites More sharing options...
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