2 My old ibm at motherboard wont recognise the keyboard
the keyboard has a switch to switch from pc xt to pc at.
the keyboard works on an xt computer.
when connected to the at motherboard and the board is powered up i can tap the caps lock and the caps lock led comes on and off as i tap it, but, when the screen shows keyboard error after booting up i can tap the caps lock and it will not change the condition of the led.
also, as the computer is powering up i can see data on the data pin of the keyboard if i am tapping any key but when the screen says keyboard error no matter which key i hit no data blip appears on the oscilliscope screen.
so it appears the keyboard only outputs data untill the computer has finished its boot.
i am stuck with a screen saying keyboard error, hit f1 to continue.
and if i hit f1 nothing happens.
Hi @whymewhyme ,
What is the model number of the motherboard?
jayeff さんによる
It says octek v 5.1 with ami bios.
peter.drury1952 さんによる
@whymewhyme
@whymewhyme
Can't find anything re the board model.
What is the IBM PC model number if known that the board may have been in?
Have you got another AT keyboard to prove whether the problem is with the keyboard or the motherboard?
Looking at the pinouts for an AT keyboard vs an XT keyboard there is no "reset" wire on pin 3 in an AT so maybe you could check if something is showing on there when it shouldn’t
Here’s a link about BIOS in early PCs which may also help.
jayeff さんによる
No other at keyboard and i didnt think it worked at all even on my xt but the xt needed a link on j3 to recognise the keyboard. And then it worked on the xt.
I put a picture of the motherboard on this site, but i dont know how you find it.
The battery has been leaking, near the din socket for the keyboard. I think that may be the problem as the din socket is eroded. I better change it first. The f1 key works to get me into the xt system.
Another thing, the at says hit delete to enter the setup program, i hit it while the at is powering up and the oscilliscope shows data on the keyboard din plug, but it has no effect on the at. And then as i said when hitting keys after it says keyboard error i see no data on the din plug. .??
peter.drury1952 さんによる
@whymewhyme
Here's how to add images to your question iFixitでの質問に画像を追加する方法.
You would think if the DIN socket was the problem that it would affect the XT operation as well given that the XT requires the reset wire in DIN pin 3 and the AT doesn't need it.
What is the make and model number of the keyboard?
jayeff さんによる
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