101 keyboard on an XT

[Anonymous Coward]

My late model IBM 5160-089 came with the IBM model M keyboard, and it works really well. But recently I wanted to upgrade to a clone board since I find the original planar to be a tad too slow to run anything useful. The replacement board is a Juko V30 of some sort. It runs pretty well, but it doesn't seem to like the Model M. I just get a bunch of garbage when I type.

Now, obviously I am aware that XT systems require XT keyboards, but isn't the model M keyboard XT/AT auto-switchable? If so, is it possible to hard wire the model M for XT mode? And if not, is there an adapter I can build or buy to make it work?

 

[Great Hierophant]

The IBM Model M is not switchable. Your late model XT has support for the 101 Keyboard built into its BIOS. The Planar did not change for the keyboard. The only thing that the Model M keyboard cannot do with an XT is to activate the indicator lights. Your clone motherboard's BIOS does not appear to have support for anything other than the original 83-key keyboard. I do not know whether this can be fixed without a (probably non-existent) BIOS upgrade. Maybe a special keyboard driver for DOS exists.

 

[mbbrutman]

The IBM Model M is not switchable.

My experience says otherwise.

Most Model M keyboards are 'Scan Set 2' keyboards, and are designed to work on the AT and clones.

Early Model M keyboards will also work on PCs, XTs, and even a PCjr with a PC keyboard adapter. The Model M electronics are smart enough to figure out what kind of system you are on and adjust accordingly. I have a model M on my PCjr and on my XT at work, neither of which are designed for it. There is a Model M (1390120) designed specifically for those machines - it is missing the indicator lights. But even Model Ms with indicator lights will work.

Later Model Ms (1994+ ?) dropped the ability to work on the 5150/5160.

The Model M does require a lot of power/current to run. It could be that the new Juko motherboard isn't supplying enough power. Another possibility is subtle timing differences. Keyboards run using a serial interface, and although it is pretty robust a small timing problem would make for some interesting results.

 

[dongfeng]

The IBM Model M IS switchable. I have three here, one 1986 model from my XT (no LEDs), one 1986 model from my AT (with LEDs) and one 1992 model. ALL of them work fine on a 5150.

From what I can work out, when IBM dropped the removable cable, they also dropped the XT scancodes.

You will have to use a driver switch to get DOS to recognise the full layout though. I have no idea how to do it for a US keyboard, as mine are all UK layout which require a driver anyway. I use PC-DOS 3.2.

In autoexec.bat I put:

KEYBUK.COM /E

KEYBUK loads the British layout, the /E means 'enhanced'

Works fine on my XT (both motherboard types) and my 5150 (1983).

For those curious about the official IBM Model M for an XT, here is a picture. It was an option on the later machines.

 

[mbbrutman]

You will have to use a driver switch to get DOS to recognise the full layout though.

Only for the 'extra' keys like F11 and F12. The extra arrow keys and editing keys show up the same as the originals, so no extra device drivers are needed. (It also means that a PC can't differentiate between the original keys and the duplicates.)


Mike

 

[evildragon]

My model M is the space saving version that came with my Model 25. My cables "clips" broke off, so I can't move the keyboard or the plug comes out all the time. kinda annoying, and I can't find that connector to crimp on a new one...

 

[Vlad]

Its a SDL to PS/2 cable.

http://www.clickykeyboards.com/index.cfm/fa/categories.main/parentcat/9417

 

[Great Hierophant]

I am very happy to be proved wrong about this.

Maybe the problem is that the motherboard cannot prove to the keyboard that it is an XT and the Model M is throwing out the AT scan codes, with the motherboard knows nothing about.

 

[dongfeng]

Only for the 'extra' keys like F11 and F12. The extra arrow keys and editing keys show up the same as the originals, so no extra device drivers are needed. (It also means that a PC can't differentiate between the original keys and the duplicates.)


Mike

I guess it must be a British layout thing. I can't get the |\ key, the `¬¦ key or the #~ key (in addition to F11 and F12) to work unless I use the enhanced switch. There might be a couple more, but I forget.

 

[Anonymous Coward]

Maybe the problem is that the motherboard cannot prove to the keyboard that it is an XT and the Model M is throwing out the AT scan codes, with the motherboard knows nothing about.

Yes, this is why I am wondering if it is possible to hardwire for XT scancodes. I thought I remember somebody saying they had a model M keyboard with a physical XT/AT switch, but perhaps I am wrong.

Do the model M keyboards consume a lot more power than the model Fs?

 

[Anonymous Coward]

Well, I figured out the problem with this one. It was a nasty combination of a faulty keyboard port and a faulty model M. I was able to get a different model M going by wiggling the connector around in the port. I guess there are some loose solder joints in there.