Problems with IBM Model M Keyboard and USB Adapter

[tsotso]

Hi all,

I'm using an IBM Model M Keyboard (actually, I have two) for several years now. When connecting them to a PS/2 port, they are working totally fine. When using with an USB Adapter on new PCs (both Windows Vista and 7), I have sporadically the following problem:
* Suddenly, all keys which I press are send to the pc as a if the ctrl-key was pressed. For example, if I press m, then ctrl+m (carriage return) receives my pc.
* this happens mostly when typing fast (when I accidentially press between two keys, together with Shift and/or Ctlr)
* It happens mostly with 'slow applications', for exmple Eclipse, Firefox, etc.
* I had this problem with the last 3 pcs (which did not have a ps/2 port)
* I tried out 3 types of USB Adapter. The last (which I ordered especially for IBM keyboards) produces this problem less often.
* I have to shut down and to power on again (just restarting Windows does not help).
* It also happens with both IBM Model M keyboards.

Has anyone experienced the same problem? For me, it seems to be independend from the USB Adapter, from the Keyboard and the PC. Does anybody knows the reason and/or the solution?

Regards,
tso

[1391406]

Which adapters are you using specifically? I'm using Windows 7 and have four Model M's which all work impeccably via USB using a PS2 to USB adapter made by Ziotek (Blue Cube).

[Ascaii]

Hmm...it might be a power issue...but I suspect it might be something different entirely. I recommend you open the board and check the rivets on the back of the metal plate. If there are a lot of the plastic rivets broken it can cause the membranes between barrel plate and metal plate to shift, causing erraneous keypresses and "stuck" keys. You will need a 5.5mm metric or 7/32" driver for the screws.

[1391406]

My first inclination is to think that's unlikely if it's happening on both of his Model M's.

[rknize]

The Wiki is somewhat light on the details of a dual-port (keyboard+mouse) adapter that works 100% reliably with a Unicomp that has a ball or trackpoint.  The one I have works great with my KVMs, but does not like to have the Unicomp plugged directly in.  It's the one with the Chesen chip and the translucent USB connector.

The "Zio" one is sold by clickykeyboards sounds promising, but the Wiki doesn't specifically state that it works completely with the Unicomp boards pointer controls.  Anyone have any idea?  Would like to know before spending $20.

[1391406]

Would like to know before spending $20.

The Ziotek adapter is going for $8.10 on Amazon.

[Thinkpad Fan]

I can't speak to the Unicomp, but I use nothing but the Zioteck (for everything) and am typing on an IBM/Lexmark M13 Black built in 1995 and everything works perfectly.  TPF

[Thagarr]

Check your motherboard BIOS for a setting something like "Legacy USB Support", make sure that is turned off. It might be called something else depending on what your BIOS is, something like "USB Speed", try different speed settings and see if that effects it any.

[Ascaii]

IF it is both keyboards then It might just be a power issue...some motherboards just don't provide enough "juice". I've tried one of my model Ms with my blue cube on the four computers in my house and I had the same issue on my ex girlfriends old p4. That boards usb ports have always been a bit wonky...try the legacy usb thing, otherwise a usb hub with active power supply might do the trick.

[tsotso]

Thank you for your answers. I ordered the USB Adapter from http://www.clickykeyboards.com/, it looks like Ziotek Adapter (8.10$ on Amazon). This USB-Adapter produces this problem less often than other Adapters (Lindy). But every 2 or 3 month, it happens again. For some days now I'm working with Eclipse, there I had this problem already 5 times.

I wonder why nobody else has this problem. Maybe the reason is that I'm a fast but sloppy typer. :-(.

[Thinkpad Fan]

It would be of great usefulness if someone tried a powered USB Hub with a Model M and reported if that solved the problem, would it not?  TPF

[Thinkpad Fan]

So if a powered Hub doesn't matter, it's not a power issue?  Then what?

[rknize]

USB ports, by default, provide 100mA of current max.  The device can request high current from the port and the port is supposed to provide up to 500mA.  It seems that many of these adapters don't do that because keyboards are not supposed to draw so much current.  

I've had plenty of fun with USB protocols and crappy hardware at work (mostly embedded, but whatever).  If the device draws more than the max, the voltage sags or collapses entirely (depending on the controller).  Some controllers do nothing and provide no port protection at all (and subsequently can cause motherboard failure).  Some do it in low current mode but not in high current mode.  Some have inadequate power supplies behind them and go flaky when they are pushed to the edges of the spec.

So a powered USB hub can fix an issue with a poorly-implemented USB port, but it won't help of the adapter is not requesting high current mode.

[tsotso]

I had the problem two times in the last days. Both times I was editing some text in a browser and I was using Ctrl+Shift+Cursor to select words backwards - incidentally I pressed between two keys, so a couple of keys were pressed simultaneously. I assume that the keyboards needs to much power in this case and the USB Adapter stops working correctly.

I have now invested some money into a Filco Keyboard with Cherry MX Blue Switches. Pressing the keys is much easier (and the clicks are by far less noisy). Maybe I have solved my problem now ...