# Computer won't post with my favorite keyboard plugged in.

M

#### mike

Jan 1, 1970
0
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

P

#### petrus bitbyter

Jan 1, 1970
0
mike said:
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2 socket.
Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

Maybe your new machine does not provide the power required by the old
workhorse?

As for the keycodes and the protocol, AFAIK they did not change.

petrus bitbyter

J

#### JW

Jan 1, 1970
0
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

If you can't get it to work in the PS/2 port, you could try a PS/2 to USB
luck with this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812120897

G

#### Geoffrey S. Mendelson

Jan 1, 1970
0
petrus said:
As for the keycodes and the protocol, AFAIK they did not change.

The protocol changed from the original PC (and XT) to the PC/AT. Since then
the protocol has not changed. The keycodes have had new ones added for various
functions such as sleep, email, etc, but the regular a-z, 0-9, F1-12, etc have
not changed since the introduction of the PC/AT.

At one point the connector changed, with the wiring being to different

USB keyboards use the same data, it's now encapsulated in USB data
streams.

Geoff.

W

#### William Sommerwerck

Jan 1, 1970
0
An XT/AT keyboard would have the older "DINnish" plug -- not a PS/2 plug. To
the best of my knowledge, they are not compatible. (But I could be wrong,
now.)

Why not replace it with a Unicomp "buckling spring" keyboard? That's what I
use.

G

#### Geoffrey S. Mendelson

Jan 1, 1970
0
JW said:
If you can't get it to work in the PS/2 port, you could try a PS/2 to USB
luck with this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812120897
Good idea to get a good one. I have many that were $2 each from China bought via eBay. They all worked (although not on MacOS) but seem to burn out after about a month. Windows recognized them with no trouble, some BIOSes did not recognize them at all, there was no keyboard support until the computer finished booting. An Office Depot brand one, which cost$10, worked fine in all of those
situations the cheap ones did not.

Geoff.

B

#### Bob F

Jan 1, 1970
0
William said:
An XT/AT keyboard would have the older "DINnish" plug -- not a PS/2
plug. To the best of my knowledge, they are not compatible. (But I
could be wrong, now.)

Why not replace it with a Unicomp "buckling spring" keyboard? That's
what I use.

I have a couple adapters that worked fine.

M

#### mike

Jan 1, 1970
0
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

Thanks, guys for the input.
I really don't want to buy yet another keyboard.
If I can find one like this with the function keys down the side
and the qwerty centered in the frame, it's likely to cost a fortune.

I'm sure I could get used to this new keyboard...I just don't want to
My fingers know how to drive this one.

with stuff that needed to be done before the system boots.

This old keyboard has worked with many different PS/2 sockets over the
years.

Measuring the power consumption is on the todo list.

I'd understand if it didn't work due to insufficient power.
But it won't let the computer even POST.

I'll have to make an adapter I can probe.

I've also got several USB keyboards with built-in touchpads.
They work well for a while, then just stop. Replugging the USB
brings 'em back. I'd like to figger out what's wrong with them too.
My workbench doesn't have any place to work a mouse.

M

#### Mark Storkamp

Jan 1, 1970
0
mike <[email protected]> said:
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

I've got one though on what your trouble might be:

Way back sometime in the late 80s, early 90s I wrote the code for a few
keyboard controllers used in clone PCs. Even though IBM had published a
spec. on the timing that keyboards were supposed to meet, many of them
didn't even come close. But they all worked with early PC hardware
because all they were using was a hardware shift register that was
tolerant of a lot of variation. When we used a micro processor (6502
based and 8047(?)) I had to build in a test to try to identify aspects
of the signal timing during POST and adapt to whatever keyboard was
plugged in. I doubt they go through all that trouble anymore.

You may get lucky and find a particular ps/2 to usb adapter that will
work.

If you're real ambitious you could program a PIC or Arduino or something
to do the translation for you.

I still have an old favorite keyboard from that era. But at this point,
if it ever gave me problems, I think I would just finally toss it.

W

#### William Sommerwerck

Jan 1, 1970
0
My experience has been that, when I get involved restoring or repairing a
favorite thing, it's not long afterward that "something happens" that makes me
want to get rid of it or replace it.

Obviously, individual reactions vary. But I warn the OP that this could
happen, and his effort to adapt the fave keyboard could turn out to be a waste
of time.

G

#### Geoffrey S. Mendelson

Jan 1, 1970
0
William said:
An XT/AT keyboard would have the older "DINnish" plug -- not a PS/2 plug. To
the best of my knowledge, they are not compatible. (But I could be wrong,
now.)

They are exactly the same electrically, I have adaptors that connect
PS/2 keyboards to AT style sockets and others that connect AT style keyboards
to PS/2 sockets.

The codes are the same, so you can buy a device that connects a PS/2
keyboard to a USB port. If you have the right adaptor, you can connect
an AT keyboard to it.

Geoff.

S

#### Sjouke Burry

Jan 1, 1970
0
I have a XT/AT keyboard that I've used for 20 years with many machines.
Works extremely well and the layout is what I want.

Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

Swapped keyboards and it works fine. But the keyboard sucks.
I've got a bunch of keyboards and they all suck. Keys stick,
keys in different locations. My old keyboard works just great.

Any ideas on what I might try to get my old keyboard to work?

Is there an xt/at switch at the bottom of the keyboard?
If so try both positions.

P

#### petrus bitbyter

Jan 1, 1970
0
John Robertson said:
Opps! Pin 2, not Pin 3 is reset! (edited above to match)

John ;-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

That "Opps" is the reason that breaking a pin would be my very last option.
It should not be that difficult to interrupt the reset line on a place and
in a way it can be restored if necessary. Very unlikely? You just proved the
opposite

I too still have an XT/AT-keyboard that works fine so far. It can be
switched between XT and AT. Differences are way to large for a simple
solution. So the switch instructs the old 8048 to use completely different
main program. But the HMOS version of the old 8048 is more powerhungry then
the newer CMOS version. Still newer processors has all of the elctronics
stuffed inside (except for the LEDs) and requires way less power.

petrus bitbyter

M

#### Michael Black

Jan 1, 1970
0
That "Opps" is the reason that breaking a pin would be my very last option.
It should not be that difficult to interrupt the reset line on a place and
in a way it can be restored if necessary. Very unlikely? You just proved the
opposite
That's simple then. Grab a female connector that matches the keyboard,
grab a male connector that matches the computer, and wire them up, leaving
off the reset line.

Or most keyboards, the cable plugs into a connector inside. So it's easy
to cut the wire there. Indeed, at one point I needed a small connector
keyboard and didn't have a suitable one, so I was going to take a cable I
did have that had the small connector and use it rather than the
keyboard's original cable.

If the keyboard really is drawing too much current, then clearly something
in the computer is between the +5v line and where the keyboard plugs in.
So bypassing that whatever would fix it, if this is the problem.

Michael

L

#### [email protected]

Jan 1, 1970
0
I have a XT/AT keyboard that I've used for 20 years with many machines.
Just upgraded to a HP Pavilion a6200n.
The thing won't post with my favorite keyboard plugged in the PS/2
socket. Just sits there with a black screen.

I've had only one motherboard do that, but I don't remember which
one or which keyboard. Every other motherboard I tried that was
incompatible caused a "keyboard error press F1 to continue" error
message.

Even if your XT/AT keyboard is designed to automatically select
XT or AT mode, it may have a jumper inside to set the default
mode, or its circuit board may be laid out for a manual XT/AT
mode selector switch that was needed by an older version of the
firmware. Sometimes you can select the default by soldering a
wire between the copper pad meant for the center terminal of the
missing switch and one of its other copper pads. Doing that made
a couple of my keyboards compatible with certain motherboards, yet
the auto-select still worked, but with other keyboards it didn't help
at all. If you feel that installing such a wire could short and damage
something, use a 200-300 ohm resistor instead.

Places like GeekHack.org and kbdbabel.com have lots of information
about keyboards, including some schematics at the latter.

L

#### [email protected]

Jan 1, 1970
0
I forgot to mention: another thing that might help is changing the value
of any power-on reset capacitor, especially if your keyboard works
when you hit the hardware reset button on your computer.

P

#### petrus bitbyter

Jan 1, 1970
0
Michael Black said:
That's simple then. Grab a female connector that matches the keyboard,
grab a male connector that matches the computer, and wire them up, leaving
off the reset line.

Or most keyboards, the cable plugs into a connector inside. So it's easy
to cut the wire there. Indeed, at one point I needed a small connector
keyboard and didn't have a suitable one, so I was going to take a cable I
did have that had the small connector and use it rather than the
keyboard's original cable.

If the keyboard really is drawing too much current, then clearly something
in the computer is between the +5v line and where the keyboard plugs in.
So bypassing that whatever would fix it, if this is the problem.

Michael

If you modify that brandnew machine you will loose all guarantee.

First thing to do is making a breakout cable and measuring the power and
reset lines using a voltage meter. Especially looking for differences
between the old and the new keyboard. Clock and data lines are important as
well but a voltage meter may not do. An o'scope will... If only you have
one.

There's one much more complex possibility for the cause of the problem:
Noise from the keyboard. Some of that older keyboards are a little bit noisy
and maybe the new machines inputs are to sensible. Fighting this problem
requires some filtering which in turn requires experience and experiments.
There's no general prescription for it.

One thing can be tried easily however: Some ferrite clamp(s) on the keyboard
cable. If the keyboard is radiating noise *and* if that noise is picked up
by the cable *and* if the computers input(s) cannot handle it *then* you
have a good chance to fix the problem with it. Conducted noise cannot be
fought this way.

petrus bitbyter

W

#### William Sommerwerck

Jan 1, 1970
0
"dave" wrote in message
...in the USA. A computer is considered "open architecture" and can be
modified by the end user without voiding a warranty. "Reasonable"
modifications attendant to the "open architecture" modus operandi are
permissible.

Adding or changing cards or peripherals? Yes. Altering the wiring? I doubt it.

M

#### Michael Black

Jan 1, 1970
0
Not in the USA. A computer is considered "open architecture" and can be
modified by the end user without voiding a warranty. "Reasonable"
modifications attendant to the "open architecture" modus operandi are
permissible.
The last "new" computer I bought was in 1989, so when I saw "new" I was
thinking it was actually a used computer new to the poster.

No, bypassing whatever current limiting there might be between the +5v
line and the keyboard is likely going to cause issues with warranty. Of
course, that only matters if you need the warranty, ie the computer fails
and you want to send it back.

Michael

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