View Full Version : Keyboard Confusion

July 30th, 2006, 01:06 PM
I wonder if anyone can shed light onto my latest keyboard problem :rolleyes:

My IBM XT has an original full-sized 102-key keyboard, it's identical to a Model M, except it is missing the LED panel as XT keyboards did not have support for them. Not long after I had the XT, it kept showing "xx 301" errors on bootup, but the keyboard worked properly. After a couple of days, it just shows "301" and I cannot use the keys. However! I can use the keyboard on my 486. The late XT 102-key keyboards autosensed between AT/XT standards.

Today I managed to get an identical keyboard! It was missing the SDL cable, but no problem as I have the one from the original keyboard.

It still gives the 301 error on the XT and I cannot type, exactly as the original had shown.

I tried this keyboard on my 5150, but also 301 error. I know only the later XT BIOS from 1986 supported 101/102 key keyboards, but I was wondering if it would work on an earlier machine, but just have some usless keys (like F11 and F12).

Anyway, to the point.

How can I tell if the keyboard is kaput, or if the XT motherboard somehow has a fried keyboard interface?

The confusing point is that the keyboard works perfectly on my 486!!! Otherwise I would suspect a faulty SDL cable.

Oh, it is confusing :mad:

July 30th, 2006, 02:35 PM
Just a thought, but what would happen if you plugged an AT keyboard into an XT and tried to use it? Would it damage the computer? I am wondering if my autosensing keyboard might have been stuck in AT mode by mistake.

July 30th, 2006, 05:10 PM
Don't put a true AT keyboard on an XT. At best it will confuse it. The differences between scan set 1 (PC and XT) and scan set 2 keyboards has been discussed here before many times.

If the keyboard works on your 486 and it is a Model M without the keyboard LEDs, then it is probably fine. (The ones without the LEDs were definitely designed for PCs and XTs.) Especially since another keyboard behaves the same way.

Find a real PC or XT keyboard, or one with a switch so that you can be sure. Then try that.

I'll be you have a problem on the motherboard, not the keyboard.

July 30th, 2006, 11:17 PM
I haven't tried to put keyboard in AT mode to XT, but when I putted keyboard in XT mode to AT computer was beeping and leds were flashing.

You don't have real problem, getting keyboard working in XT mode is very easy.
Many keyboards till early '90 had switch hidden somewhere, maybe your 286 or 386 have such keyboard?

Problem is, if keyboard killed keyboard chips in both machines...

I could send you one suitable for XT's and PC's, but shipping would be expensive.
As I remember Terry send you a keyboard, did it arrived?

July 31st, 2006, 12:34 AM
Unfortunately the only keyboard I have is this 102-key XT. My 286 has a special Epson keyboard that doesn't fit in the XT so I cannot try it.

The keyboard Terry Yager sent me has not arrived yet, but I think it should do soon as it was a just over a month ago he sent it. I will try it when it arrives!

Has anyone ever tried a 101/102 key IBM keyboard on a 5150?

Is it possible to kill keyboard interface with AT keyboard?

July 31st, 2006, 01:32 AM
I haven't tried 102 keys keyboard on 5150, but on XT from '85.
You won't be able to use F11 and F12 keys, that 5150 can't handle.

mbburtman wrote:

The 5150 and the first 5160s used the 83 key keyboard, which speaks 'scan code set 1'.

I don't know what he mean by firs XTs, I think that these with 256Kb mainboard.

If keyboard is broken, then it can damage keyboard chip.
But I think that the keyboard is just bad.

July 31st, 2006, 01:51 AM
I think you are right, I just tried the "new" 102-key keyboard on my 486 and it does not work. As it does not work on 5150, XT or 486, I think I have faulty SDL cable! Or, the "new" keyboard is broken. On 5150, it "bleeps" every time a key is pressed, but no letters appear.

First XT is with 256kB mainboard. Second XT is 640kB mainboard, also had support for 101/102 key keyboards and 720kB floppy drive :)

July 31st, 2006, 05:48 AM

Wrong. You can use almost all of the keys on a Model M that was designed for an XT. The duplicate extra keys will use the same scan codes as the existing keys. At worst case only the new keys (F11 and F12) will not work.

When I said first XTs I was referring to, well, the first XTs. Those came with the standard 83 key keyboard used on the PC. On later XTs you had the option for the extended keyboard, which was a Model M.

Please, use google or something like that for the basics on how PC keyboards work. It's all out there.

July 31st, 2006, 06:04 AM
Okay, I wrote it in wrong way, sorry.

July 31st, 2006, 06:45 AM
It's not a scolding, but other people may refer back to these forums for advice on their keyboard problems and I don't want to perpetuate any misinformation. We need to be pretty accurate here, and cleanup after ourselves if we goof.