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Anybody know why an XT does this?

J

jonnymacuser

Experienced Member
Joined
Aug 4, 2011
Messages
70
Location
california
Booted up an XT 5160 with a "640 KB OK" status, then the system goes to this:

xtboot.jpg





Totally unresponsive via the keyboard, only more and more ===== signs appear with keystrokes.


Anybody recognize this problem?
 
Known working keyboard?

If not have you tried unplugging the keyboard after its powered up?

If that doesn't stop it my best guess would be the keyboard controller chip.

-Matt
 
I think thats the length of the keyboard buffer ... If you have a correctly working machine in basic and you type random characters without hitting enter you'll get about that far before the system freezes. The special ascii character on your screen is I assume a coincidence. I am guessing the computer itself is ok.

To prove you have a bad keyboard.. Boot up the system with the keybd attached and then unplug it immediately after rom post. If you time it correctly you'll boot into basic without the chars appearing or you'll stop the full spread.

what do pc/xt class replacement keybds cost? try cleaning the keybd.
 
Need more info. Is your concern surrounding the bootup, or the keyboard?

If bootup: Has this machine ever booted correctly before? If so, did it boot to an internal hard drive or into the ROM BASIC? Can it currently boot from a floppy disk?

If keyboard: Does this behavior persist with a different keyboard?
 
If one leaves the keyboard unplugged during a boot, won't a 5160 simply post an error and then continue anyway?

Very easy way to see if it's the keyboard.
 
The black foam in the keyboard goes dusty and causes such problems. Take it apart (two screws, don't worry it won't fly apart in a million directions), take out the main guts of it then blow out right between the keys with a can of compressed air. be careful not to make it too cold (which might encourage condensation to form). Reasssemble and should be good :)
 
This was a Keyboard issue!

Its amazing how spot on the help was -- thank you hexsane, billdeg, deathshadow, Trixter, Chuck(G), lutiana, and pearce_jj!


This particular 5160 had been sitting for a long time -- although reportedly working before being stored -- but yet sitting for quite some time (possibly 10 or more years).


Opened up & cleaned the dust and decaying foam out of the the Model F.


ibmmodelf.jpg

modelfscrew.jpg

ibmmodelf2.jpg

modelfconn.jpg



Then booted up into Basic with the display reading:

The IBM Personal Computer Basic
Version C1.10 Copyright IBM Corp 1981
62940 Bytes free
Ok
_


And then a upon a second boot-up got the hard drive spinning & roaring to life and booted into some version of DOS with the command promt at C:/>_



..
 
jonnymacuser said:
Then booted up into Basic with the display reading:

The IBM Personal Computer Basic
Version C1.10 Copyright IBM Corp 1981
62940 Bytes free
Ok
_


And then a upon a second boot-up got the hard drive spinning & roaring to life and booted into some version of DOS with the command promt at C:/>_

..
Click to expand...
Well done!
I see the Basic version there, but I don't think that supported a HDD, so you probably have DOS 2.0 or later. Type "ver" to see. Also the prompt you are seeing is just the default. Since version 2.0 there has been an internal (built into command.com) command to make it whatever you like best. For example have it show the time, or some message, version, ansi colours, or whatever. The "ver" command is also internal (to ver 2.0 and later) and you can type "ver /r" for more details.

BTW: doesn't that keyboard feel GREAT to type on? :)
 
Glad it's sorted. Expect further problems though, usually cured (in my experience) by tapping it upside-down and then blowing out the dust again. Maybe one day I'll pull one right apart and see what's going on inside.
 
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