IBM XT 5160 Keyboard issues

Fred Cisin cisin at
Sat Dec 17 23:59:51 CST 2016

On Sun, 18 Dec 2016, Devin wrote:
> I was happy to find a IBM XT for a good price at the scrapyard today in very 
> nice condition. It is missing the hard drive, but i have plenty of those, the 
> controller was still inside.

If it is the real IBM (Xebec) hard disk controller, then it is strapped 
for 10M.
Near the center are 8 solder pads.  If you want, you can solder a 4 
position DIPswitch to them, or just solder jumper wires as needed.  It 
supports two drives, two jumpers per drive.  All open is 10M. (306 
cylinders, 4 heads).  IIRC, without modification other than those jumpers, 
it supports 5M, 10M, 16M, and 26M?
Other configurations of drives can be accomplished by changing the ROM, or 
in software.

> I had a little issue getting video working at first, i do not have a 9 
> pin cga monitor laying around, thankfully i found a 16 bit isa card that 
> also works in an 8 bit slot.

If it is a CGA card, then it also has an RCA jack and a 4 pin berg for 
composite video, along with DE9 for CGA monitor.
If it is MDP, then it has DE9 for video and a DB25 for printer.
Pay close attention, they do NOT have the same frequency!

> The machine starts up and runs its memory test, however it gives a 301 error. 
> System halts and says press f1 to continue, but no luck, keyboard is 
> unresponsive. I have tried about 10 different keyboards on the machine, 
> including some model M keyboards with a ps2 adapter with no luck.

XT (5160, as well as 5150) keyboards are NOT interchangeable with AT 
(5170) style keyboards.  An AT keyboard will not work on an XT nor 
vice-versa.  For a brief time, there existed some keyboards with an XT/AT 
switch on the under side.
Any keyboard with a PS2 adapter would be an AT keyboard.  The XT keyboards 
never had any connectors other than the 5 pin DIN.

> Am i doing something stupid here or am i looking at the possibility of 
> something being wrong with the machine?

You are right that a 301 error is keyboard.
You need to find an PC/XT keyboard; an AT keyboard will NOT work.
(Not even 10 of them :-(  )

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