[Resolved] Help with an IBM XT, inputs random characters

kmnov2017

20 May 2019, 23:42

I recently restored an IBM XT.

It worked fine for a 2/3 days, but now the keyboard is inputing characters on its own and completely unresponsive.

I ran HID listen and got the following.

Help!

r80 -00 r00 +00 r00 r80 -00 r80 r00 +00
r80 -00 r00 +00 r00 r80 -00
r80 r00 +00
r80 -00 r00 +00
r00 r80 -00 r00 +00
r80 -00 r80 r00 +00 r00 r80 -00 r80 r00 +00
r80 -00 r00 +00
r00 r08 +24 d24 r88 -24 u24 r80 -00
r80 r00 +00
r80 -00 r00 +00
r00 r80 -00
r80 r00 +00
r00 r80 -00
r80 r00 +00 r80 -00 r00 +00 r80 -00 r00 +00
r80 -00 r00 +00
r00 r80 -00
r80 r00 +00 r80 -00
r00 +00
r00 r80 -00 r80 r00 +00
r00 r80 -00
r80
r00 +00 r00 r80 -00
r00 +00 r80 -00 r80 r00 +00
r00
r80 -00 r00 +00 r80 -00
r00 +00 r80 -00 r00 +00 r80 -00 r00 +00 r80 -00
r00 +00 r80 -00
r80
r00 +00 r00 r80 -00 r80 r00 +00 r00 r80 -00 r08 +24 d24 r88 -24 u24 r00 +00 r80 -00
r00 +00 r80 -00 r00 +00 r80 -00 r80 r00 +00
r80 -00 r00 +00
r80 -00 r00 +00
r00 r80 -00 r00 +00 r80 -00 r80 r00 +00 r80 -00 r00 +00 r00 r80 -00
r00 +00 r80 -00
r80 r00 +00
r00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r00 r80 -00 r80 r00 +00 r00 r80 -00
r00 +00 r80 -00
r80 r00 +00
r00 r80 -00
r80 r00 +00
r00 r80 -00 r80 r00 +00 r80 -00 r00 +00
r00 r80 -00 r00 +00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r80 -00 r00 +00
r00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r80 -00 r00 +00 r80 -00 r00 +00
r80 -00 r00 +00
r80 -00 r00 +00 r00 r80 -00
r00 +00
r80 -00
r80 r00 +00
r80 -00 r00 +00
r80 -00 r00 +00
r00 r80 -00
r80 r00 +00 r80 -00 r00 +00 r00 r80 -00
r00 +00 r80 -00 r00 +00 r80 -00 r00 +00 r80 -00
r80 r00 +00 r80 -00 r00 +00
r00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r00 r80 -00 r00 +00 r80 -00 r00 +00 r80 -00 r00 +00 r80 -00
r80 r00 +00 r00 r80 -00
r80 r00 +00 r00 r80 -00 r80 r00 +00 r80 -00
r00 +00
r00 r80 -00 r00 +00 r80 -00
r00 +00 r80 -00 r80 r00 +00
r00 r80 -00
r80 r00 +00
r00 r80 -00 r00 +00 r80 -00
r80 r00 +00 r80 -00 r00 +00
r80 -00 r00 +00 r80 -00 r00 +00 r00 r80 -00
r00 +00 r80 -00 r00 +00 r80 -00 r00 +00
r80 -00
r80 r00 +00
r00 r80 -00
r00 +00 r80 -00 r80 r00 +00
r00 r80 -00
r80 r00 +00 r80 -00 r00 +00 r00 r80 -00
r80 r00 +00
r00 r80 -00
r80 r00 +00
r00 r80 -00 r80 r00 +00
r80 -00 r00 +00
r80 -00
r00 +00
r00 r80 -00 r80 r00 +00
r80 -00 r00 +00 r00 r80 -00
r00 +00 r80 -00
r00 +00 r80 -00 r00 +00 r80 -00
r80 r00 +00 r80 -00 r00 +00
r80 -00 r00 +00
r80 -00 r00 +00
r00 r80 -00 r80 r00 +00 r80 -00 r00 +00
r00 r80 -00
r00 +00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r00
r80 -00 r80 r00 +00
r00 r80 -00 r80 r00 +00 r80 -00 r00 +00 r80 -00 r00 +00
r00 r80 -00 r80 r00 +00
r00 r80 -00 r80 r00 +00
r80 -00 r00 +00
r80 -00 r00 +00
r00 r80 -00 r80
r00 +00
r00 r80 -00
r80 r00 +00
r80 -00 r00 +00
r00 r80 -00
r80 r00 +00 r00 r80 -00
r80 r00 +00
r80 -00 r00 +00
r00 r80 -00 r80 r00 +00 r00 r80 -00
r80 r00 +00
r80 -00 r00 +00 r00 r80 -00 r80 r00 +00
r80 -00 r00 +00 r00 r80 -00
r00 +00 r80 -00 r80 r00 +00
r80 -00 r00 +00
r80 -00
r00 +00
r80 -00 r00 +00
r80 -00 r00 +00 r80 -00 r00 +00
r80 -00 r00 +00 r00 r80 -00 r80 r00 +00
r00 r80 -00 r00 +00 r80 -00 r00 +00 r80 -00 r80 r00 +00 r80 -00 r00 +00
Last edited by kmnov2017 on 22 May 2019, 09:22, edited 1 time in total.

User avatar
snacksthecat
✶✶✶✶

21 May 2019, 00:47

Make sure the screw(s) that hold the controller board to the plate are not loose. It is most likely a grounding problem on the keyboard.

Sounds like you’re using a skater’s converter. Did you make it yourself? This could be another source.

Spoiler:
By “skater’s” I mean “soarer’s”

kmnov2017

21 May 2019, 01:20

The converter definitely works - I’ve been using it on several other keyboards. The PCB is well grounded.

kmnov2017

22 May 2019, 00:50

Finally I managed to fix it! The culprit was the clock and the data cables kept shorting. Somehow this seems to happen only when the case was closed. Used some electrical insulation tape to fix it. A full restoration post will follow...

User avatar
snacksthecat
✶✶✶✶

22 May 2019, 01:13

Cool, I'm glad you got it working. And thanks for posting the solution too. Now I know a new thing to look for.

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