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IBM 5150 keyboard problems

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Ozfer

Experienced Member
Joined
Jan 15, 2014
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82
Location
Connecticut USA
Hey guys I'm still working on my 5150 project and I have made some progress since my lasts posts and now I have a Model F keyboard and a working VGA card connected to a monitor.

Now when I start the computer up it goes into IBM basic and I can't use the keyboard. I have it plugged into the "keyboard" port and the guy I bought it from knows that it works. Also sometimes I see a random character appear on the screen and I'm not sure what causes it. It is probably an issue with the pc but I have no idea what. Any Ideas?

Also sometimes I get parity error 2. It happens randomly and I have no idea why. Sometimes it boots up fine without parity error and sometimes it gets parity error.
 
Ozfer said:
and now I have a Model F keyboard ... and I can't use the keyboard. I have it plugged into the "keyboard" port and the guy I bought it from knows that it works.
Click to expand...
I presume that you are seeing a 301 error on-screen at boot time. Are you?

Per http://deskthority.net/wiki/IBM_Model_F, model F' keyboards cover quite a range of keyboards, and includes one for the IBM AT. So, do you know that yours is one for the PC or XT, and not AT ?

Ozfer said:
It is probably an issue with the pc but I have no idea what. Any Ideas?
Click to expand...
See note 13 at the bottom of http://www.minuszerodegrees.net/5150/misc/5150_post_and_initialisation.htm

Ideally, obtain a second XT-class keyboard, and then quickly prove either the keyboard or motherboard at fault.

Assuming that your keyboard is an XT-class one, and that it is good, something that may (repeat: may) reveal a cracked solder joint on the motherboard's keyboard connector, is to power up the 5150 multiple times, each time holding the keyboard's connector at a slightly different angle.

Ozfer said:
Also sometimes I get parity error 2. It happens randomly and I have no idea why. Sometimes it boots up fine without parity error and sometimes it gets parity error.
Click to expand...
If the motherboard switches in your 5150 are configured properly, then PARITY ERROR 2 results from a RAM parity error on an expansion card that provides RAM. I suggest that the first thing you try is to re-seat all RAM chips on the expansion card/s that is/are providing RAM.
 
Okay it does have a expansion ram card and I will try that. Wow I didn't know those were error codes since it never beeped or anything but it does say this when booting up.

6020 201
301
131

Possible causes:
1. It cant be that its not compatible.
2. Its in the keyboard port.
3. The keyboard is attached.
4. It has been tested working.
5. It has been tested working.
6. It has been tested working.
7. Faulty motherboard - bad solder joint on keyboard connector.
8. Faulty motherboard - faulty keyboard circuitry.

Oh yay now what do I do :/ I don't really just have a second XT keyboard laying around. I will try some things later when I get some time.
 
Yeah, I think Stone is trying to say that if the previous ownder of the keyboard knows that it's a good keyboard, it's unlikely that it was recently tested on a XT machine.
Not many people keep an XT machine around.
 

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If there was a code following the 301 I'd suggest the keyboard might have been damaged in shipping e.g. a plate slipped but there wasn't.
You'll need to test it out on another XT that you know works. (Which I figure you don't have, so that's a bit of a pain).

Edit: looking back, I'd follow what modem7 suggested.
 
It says IBM personal computer and my 5150 says IBM personal computer and they have the same connector but they don't work together ? D: I also bought a ps2 adapter and that didn't seem to work either but I blamed the adapter since it was cheap. It always gets the same error code no matter what I have plugged in or if I don't have anything plugged in.

I thought this IS the pc series this doesn't have a 286 and it is a 5150 shouldn't it work?
 
From your pictures, I recognize that as an XT-class keyboard (Identical to all the ones I've seen, including my own which works on a 5150 and 5160), so it should be compatible with the 5150.

A PS/2 keyboard with an adapter certainly** won't be compatible. The two basic types of PC keyboard are XT and AT. All PS/2 keyboards are AT-compatible as far as I know. I've never encountered a PS/2 keyboard that is XT-compatible.

Some AT keyboards have an XT/AT mode switch, and can be used on either (the connector is the same).

Assuming from the above that your keyboard is in fact 5150-compatible, I'd start looking for either a faulty motherboard keyboard connector, faulty keyboard cable or connector, corroded pins, or similar. Maybe someone can chime in as to whether the 5150 has a keyboard BIOS that could have failed...


**See Stone's comment below... Model M PS/2 keyboards may still support XT/AT autosensing
 
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I would be looking at the keyboard controller, or the connector on the motherboard. As that keyboard was good when it left, as verified by IBM Advanced Diagnostics, otherwise I wouldn't have released it into the wild. Could one of the other boards in the machine be interfering with the operation of the keyboard?
 
Easiest way to tell a XT compatible Model M is a silver badge in the top left rather than a circular IBM logo. Unfortunately they aren't very common.
 
Blinkenlightz said:
Maybe someone can chime in as to whether the 5150 has a keyboard BIOS that could have failed...
Click to expand...
k2x4b524[ said:
I would be looking at the keyboard controller, or the connector on the motherboard. As that keyboard was good when it left, ...
Click to expand...
Unlike the IBM 5170, the 5150 (and 5160) do not have a keyboard controller chip on the motherboard.
 
Ozfer said:
Okay it does have a expansion ram card and I will try that. Wow I didn't know those were error codes since it never beeped or anything but it does say this when booting up.

6020 201
301
131
Click to expand...

"6020 201" --> RAM error in bit 5 at address 384 KB.


"301" --> Keyboard error (POST did not receive byte AA from keyboard within required timeframe).

The earlier emails have established that your keyboard is good and is compatible with the 5150.
That leaves a bad solder joint on the motherboard or faulty keyboard circuitry on the motherboard.

The earlier post [here] is an example of a 5150 owner discovering a bad solder joint on the motherboard's keyboard connector.


"131" --> Cassette port problem.

See note 12 at the bottom of [here].
There has been at least one VCF user who got rid of the 131 error by reseating plug P9 from power supply.
 
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