IBM Model M keyboard PS/2 problem

[genegold]

Hello, it's been awhile since folks here helped me in get started with an IBM Model M, 1391401.  Four years and some to be exact.  In the past day, a big problem has arisen.  I've had the kb plugged directly into the PS/2 port of a few mobos, the current one since last year being a Gigabyte GA-Z68X-UD3H-B3.  Normally upon computer startup, the kb lights flash once or twice and then at some point in the process the NumLock light comes on and the kb works fine.  Instead, yesterday one time and this morning continuously the Caps Lock and Scroll Lock lights have come on immediately with power, while the NumLock light never comes on, and the kb doesn't work, i.e., no response from the keys.  Yesterday, unplugging and replugging into the PS/2 port fixed it, but today it hasn't.  For now, I've got it going using a PS/2 to USB adapter, but that's not optimal, as it leaves me w/o anymore USB ports - and that's with an add-on card.  So, anyone have an idea what might be going on with the direct PS/2 connection?  Thanks,

[Hellmark]

Do you have any other machines with PS/2 ports around? I'd try on those, and if you have the same results.

If you have the same results with other systems, then I'd wager that the processor has an issue to where it is starting to get flakey. I've seen some instances where it will work with some and not with others, because one of them doesn't have the same standards that the other has. Having things work on the USB adapter but not the PS/2 port may explain this (Most USB adapters can be a little slipshod, so let ****  through that onboard ports wouldn't).  If you have a multimeter, I'd check things out, starting with the resistors (common point of failure).

If it works everywhere else but the one system's PS/2 ports, then that may have crapped out, unfortunately. I've seen some crappy PS/2 ports on things, and the Model M can be a bit demanding. If you had a bad component, or something that is poorly designed, the M's higher than normal power draw could have killed it. If that is the case, it was only a matter of time, even if you used a POS rubber dome.

[genegold]

Thanks.  I have a Kensington USB-PS/2 compatible keyboard and just realized I have a USB female to PS/2 adapter to use for testing.  To be continued...

[rowdy]

If I understand correctly, the 1391401 has a detachable cable.

You could try getting one of orihalcon's SDL to USB cables - they are highly recommended (using one right now, as it happens).

[genegold]

thanks, I had forgotten all about that plug.  Unhooking it, moving things around and rehooking got things back to normal.  Those SDL cords aren't cheap...or plentiful.

[fohat.digs]

Those SDL cords aren't cheap...or plentiful.

If you can bear to spring for one of Orihalcon's direct SDL-to-USB cords you will be delighted with what you get.

[genegold]

Read his post so I'm sure they're great, and I've bookmarked it.  As mentioned in my OP it would take up my last USB port and I'm already using an add-on card.  Someone has about 10 12-footers on eBay and I went for one.  Just hope the longer length doesn't cause electrical problems.  I noticed it did with Orihalcon's USB cords.

Update: darn, missed this: Jameco.com has extensions for $5 + shipping.  Search "PS/2 cable"

[rowdy]

Have you considered a USB hub?

Not for everyone (due to portability or space concerns), but I'd be lost without mine.

[genegold]

No, maybe if I go to more external devices, but I do have an extra front USB port when needed.  Unfortunately, one of the wires on the front USB 3 header got smashed down, so that's limited things.  A related problem I've recently encountered is that the laser USB mouse transmitter is causing electrical noise through powered speakers, depending on the shielding (or not) of unbalanced ICs (and speakers) being used. 

[fohat.digs]

Have you considered a USB hub?

Not for everyone (due to portability or space concerns), but I'd be lost without mine.

Powered USB 3.0 hubs have given me fits on boot-up, but good-quality non-powered 2.0 hubs are great - I keep my keyboard and 2 mice in one and I boot properly.

In the back, on the floor, in the tangled mess, I have a powered 7-port 2.0 hub that runs printers, scanners, headset, other stuff. A front panel card reader is essential to me, but if it has a built-in USB port that usually dies after a year or 2.

PS - I avoid wireless "anything" like the plague.

[genegold]

What hub did you end up with?  My computer is on the floor underneath too.  In addition to the usual USB connections, including two printers, there's a dac coming out the back via USB adapters, plus an external power charger and and a pair of ICs.  If a hub worked right, it might make dealing with all that wiring a bit easier.

My kb problem appears to be the cord.  The keyboard went on the blink again last night after several hours of going well, probably after moving around some cables on the desktop and down behind the computer.  Through testing, I know it's not the IBM kb itself - I'm using it now via USB - and apparently not the mobo's PS/2 port either, as a Kensington USB-PS/2 kb worked, at least long enough for a quick check.  Hopefully, the IBM cable I ordered will solve it.

[fohat.digs]

The non-powered "primary" hub is a Toshiba. The powered 3.0 is a SIIG.

The buried one is a 7-port that I bought on ebay is an Inland, but I have used no-name ones from China that worked fine.

[genegold]

LOL.  Looks like you've got a couple ICs running down there, so I assume some kind of decent speakers.  Are you picking up extra noise at all through them?

[fohat.digs]

LOL.  Looks like you've got a couple ICs running down there, so I assume some kind of decent speakers.  Are you picking up extra noise at all through them?

The system is generally pretty quiet. I have a Creative Elite X-Fi Pro card + outboard unit that was really top shelf about 6-8 years ago, and a 5.1 Altec Lansing speaker system with a fairly small sub woofer. I have a Technics direct drive table with Audio-Technica cartridge and and outboard preamp. I use this for recording vinyl (and the very occasional cassette) and playback of my digital collection.

My "proper" stereo system in the other room is mid-level late-1980s gear that still works and sounds great.