IBM Model M + Blue Cube = No response :(

[Zikki]

Hi everyone,

I've purchased IBM Model M keyboard (71G4639) from Ebay and 'Blue Cube' ps2->usb adapter from Cablestar.

When I plug the keyboard  into the usb port of my netbook, the leds on Model M instantly light up and then go off. But the keyboard stays unresponsive.

Any ideas? Could it be the case that the USB power of my netbook is not enough for Model M? If so, can active USB hub solve this problem?

Any help is appreciated.

ps. I've got another ps2 keyboard (not model m, simpler and newer one), when i plug this one the leds light up, then go off, and then numlock turns on and the keyboard work flawlessly. So presumably 'Blue Cube' works fine...

[escargot]

Have you tried the Model M on a desktop computer with a PS/2 port? That would be the first step I'd do to see if the Model M works at all. Well, I'm not experienced with the blue cube, so I can't say anything about the symptoms.

[Zikki]

Thanks, Escargot.

This is another problem — I don't have any computer nearby with ps2 port. Only USBs and only notebooks =(

[theferenc]

The power draw over USB shouldn't be a problem. Doesn't the USB spec allow for 250mA by default, and higher with the correct driver?

The M only takes about 100mA, which is a lot for a keyboard, but not for a USB device.

Not sure if this helps, but using the Belkin adapter, I've used mine with a newer macbook pro without issue.

You know the adapter works with newer keyboards that draw less current. It's possible you got a different revision of the adapter, as not all adapters work with the Model M, so if the firmware/controller changed in the blue cube, that might do it.

The Dynex adapter from BestBuy works decently well with the M. The similar looking store brand from Staples does not. But you could try a different adapter.

I suppose it's possible there's a problem with the keyboard controller, but it seems that it's at least getting power, based on the lock lights. That's all mine does when I plug it in, but it also works.

I know that wasn't super helpful, but that's all the advice I can offer without more information to help narrow down the problem.

And welcome to Geekhack!

[Zikki]

Thanks, Theferenc and Ripster. I hope that geekhack would help me to bring model m to life.

I'm not sure, whether wikipedia is a good source, but:
http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power
A unit load is defined as 100 mA in USB 2.0, and was raised to 150 mA in USB 3.0. A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0, which was raised to 6 (900 mA) in USB 3.0. There are two types of devices: low-power and high-power. Low-power devices draw at most 1 unit load, with minimum operating voltage of 4.4 V in USB 2.0, and 4 V in USB 3.0. High-power devices draw the maximum number of unit loads supported by the standard. All devices default as low-power but the device's software may request high-power as long as the power is available on the providing bus

So, it seems like there is no other way to test if there is an issue with underpowered USB, but to wait while a powered USB hub arrives.

Apart from that I've just tried to connect model m to my netbook once again and the combination that model m leds give me as follows:
num off, caps on, scroll on
then in a second
num on, caps on, scroll on
and then immediately
num off, caps off, scroll off

Can this tell anything regarding possible malfunctioning of controller...

[False_Dmitry_II]

7XGXXX? Isn't that rubber domes anyway?

[Zikki]

False_Dmitry_II, yes it's rubber domes, but with BS noise is an issue...

[False_Dmitry_II]

Ah. Where I am in the house, it would have to be a few hundred times louder to bother anyone else.

[Zikki]

Well probably this keyboard will end up as a good picture installation on the wall.
Got active hub — and still no positive result from the keyboard.

[BucklingSpring]

Well probably this keyboard will end up as a good picture installation on the wall.
Got active hub — and still no positive result from the keyboard.

Test your keyboard in a PS2 plug as suggested. Could be a defective "blue cube" as well.
I'm not familiar with your USB/PS2 adaptor but the one I use for my IBM keyboards was quite expensive (30$ range) and much bigger than the half finger size little piece of junk that usually come with mouses and standard keyboards (green and pink).

[Zikki]

Thanks, Bucklingspring,
But this blue cube adapter is working absolutely fine with other keyboards, moreover, it is the one that was recommended here to buy. So if it works normally then it should 'support' my model m. Apparently, the thing is... that it's broken.

I'll have to wait for some other machine with ps2 port to test it though...

[Chaoticmass]

Check your SDL connector to the keyboard. I have a two model m's that work great but seem to have issues with the SDL connector. On one of them the connection is a bit loose and if it's wiggled the wrong way it loses the connection. Another one seems to fit tight and click in, but the keyboard doesn't respond even though you see the LEDs flash at first. You have to push the connector in harder for it to get a good connection. I don't know if this is common or not, but as I said, i have two model m keyboards that have dodgy SDL connectors. It's something to try at least.

I've used some really cheap USB to PS/2 adapters on my desktop at work but haven't tried them on a laptop.

[Zikki]

Thanks, Chaoticmass

My version of model m doesn't have an sdl connector, the cord is completely integrated.

>>Another one seems to fit tight and click in, but the keyboard doesn't respond even though you see the LEDs flash at first.<<

You mean that working leds on the keyboard don't indicate that the connection is ok?


Thanks for the tip though, I'll probably try to see if there is a problem with loose (broken) connections inside the keyboard and ps2 port itself.

[theferenc]

It doesn't mean you have a stable connection, no. You might get a slight power surge, enough to light up the LEDs, without being stable enough to actually power the device.

[Zikki]

Ok.
Having spent some money on nut screwdriver I opened the keyboard and found that yellow and white wires from the cord are broken, after some fixing works, I'm typing this message on model m keyboard.

But there is another problem — I can't close the lid of keyboard, no matter how I try, after fixing the nut screws the opposite side of the keyboard opens up. Is there some trick to easily close keyboard?

Thank you all for the support.

[Zikki]

Hey Ripster,

Of course, I first engage tabs, but when I start tighting the screws, the the other end of the upper lid jumps up and. I just want to check if this is a common issue with these keyboards and may be there is some remedy/technique to tackle this.

[ch_123]

Could be dried out caps.  M2s have that problem.

AFAIK, the problems with the M2 were largely to do with it using surface mount components when surface mount was brand new. Older Model M controllers are through-pin, the 42H1292 are probably surface mount, but would have been designed when the technology was a bit more mature.

Hey Ripster,

Of course, I first engage tabs, but when I start tighting the screws, the the other end of the upper lid jumps up and. I just want to check if this is a common issue with these keyboards and may be there is some remedy/technique to tackle this.

You should be able to snap them closed, but I've never seen one open that much. Could be some issue with the case on your one.

[theferenc]

I rarely bother with engaging the tabs fully until after I get the case screwed close. Without proper tension, they have a tendency to come loose anyway while you are closing up the case.

Just snap em down, it'll be fine.

[ch_123]

All Caps dry out eventually.

I've worked on enough old Fender Guitar amps to know this well.

True. I think the issue with the M2 was that they didn't take well to long periods of inactivity.

[Zikki]

>>You might have something going on with the main assembly not sitting properly.

Thanks, Ripster. Indeed after soldering some wires inside the plate the metal plate was not sitting properly inside, now everything is fixed. Works and looks just fine!!!

Thank you all for your help.

Off: Ripster, BTW, you told that unicomps arent THAT bad, i.e. you mean that unicomp keyboards are worse than original model m? if so in what way, since I was thinking of buying one later...