IBM Model M and Blue Cube - unresponsive

[marketfresh]

Hello everyone,

Long time lurker on Geekhack, and I finally got my hands on a Model M.

My Model M has the Part No. 60G3571. While my PC has a PS/2 port, the keyboard was unresponsive even though the computer said it is working properly.

Nonetheless, I purchased an active adapter from Amazon (blue cube) and still, the same problem persists. PC recognizes it, but none of the keys do anything and the keyboard LEDs do not come on.

Has anyone experienced anything similar? Any idea what I can do? I certainly hope its not a dud keyboard but it was in its original packaging.

I also checked voltages inside the case with a multimeter. Red, Black, and Yellow cables all registered about 5v.

[chyros]

Just to check, you didn't hot-plug the keyboard by any chance, did you? PS/2 ports do not support hot-plugging.

[marketfresh]

I don't believe I have, and I am familiar with what you mean. These were my basic steps:

1. Connected Model M to PC with "passive" adapter. This didn't work.

2. Turned off PC, connected to PS/2 Port, rebooted. PC recognized a keyboard in the PS/2 slot, but keyboard is unresponsive and lights do not register.

3. Connected Model M to PC with blue cube (http://www.amazon.com/gp/product/B000BSJFJS?refRID=2NZ0JEDH3BDPW5N8GNB6&ref_=pd_ybh_a_1). Same as with passive connection.

I notice with the blue cube, when I unplug the keyboard but leave the blue cube in, my PC still says there is a keyboard connected.

Could this have damaged my keyboard? Unfortunately I do not have another PC/PS/2 keyboard I can try, though I may swing by my local thrift store and get a $1.00 one just to test the cube.

EDIT: I opened up the keyboard case and everything looks sound - nothing shorted out, burnt out. I found it online in its original packaging, so nothing should be amiss I think...

[Snowdog993]

I don't believe I have, and I am familiar with what you mean. These were my basic steps:

1. Connected Model M to PC with "passive" adapter. This didn't work.

2. Turned off PC, connected to PS/2 Port, rebooted. PC recognized a keyboard in the PS/2 slot, but keyboard is unresponsive and lights do not register.

3. Connected Model M to PC with blue cube (http://www.amazon.com/gp/product/B000BSJFJS?refRID=2NZ0JEDH3BDPW5N8GNB6&ref_=pd_ybh_a_1). Same as with passive connection.

I notice with the blue cube, when I unplug the keyboard but leave the blue cube in, my PC still says there is a keyboard connected.

Could this have damaged my keyboard? Unfortunately I do not have another PC/PS/2 keyboard I can try, though I may swing by my local thrift store and get a $1.00 one just to test the cube.

EDIT: I opened up the keyboard case and everything looks sound - nothing shorted out, burnt out. I found it online in its original packaging, so nothing should be amiss I think...

I am not too sure, but this sounds like a problem with the ribbon connection.  Is this a 3rd or 4th generation keyboard?  When you open it up, are there two ribbon cables connected to the controller, or is the controller on the upper right-hand side?  (Where the LED's are located)

If it happens to be the dual ribbons, it might be as simple as using a pencil eraser on the contacts on the ribbon, and reseating the ribbons into the controller.  Since there is no LED response, I am suspicious there is a communication problem between the controller and the membrane.

Can you take a picture of the controller and (hopefully) the ribbons connected to it?

If it's a 4th gen, the controller and LED's are connected on the upper right side.  You will have to (VERY) carefully remove the controller, clean the contacts, and line up the controller to the membrane and hope for the best.  Be careful, there is a plastic hook that you have to re-connect.  It is used to provide tension to the controller to the membrane.  If you break that little hook, you might want to try gorilla tape (or duct tape) and use that to hold the controller in place at about the same angle.

Good Luck!  (I want to see the picture first!)

[rowdy]

Welcome to Geekhack!

Agree with Snowdog993 - the first thing to check is the ribbon cables inside the keyboard.

[marketfresh]

Thanks for the tips guys, I really appreciate the help.

So I removed the cover and checked the connections. Here is a photo of the LED membrane: http://imgur.com/K2iQ6u9

I gave all the connections a good scrub with an eraser, and tried again. No dice.

Then I decided to grab my multimeter and measure the resistances across the membrane from the main board connection to the LED hookup. I couldn't get a single lead to register any change in resistance beyond the normal air. if Im getting full resistance from every lead, is the membrane bad? Can I replace it/bolt mod my ibm at the same time with this?

http://www.pckeyboard.com/page/product/MEM

[Snowdog993]

Thanks for the tips guys, I really appreciate the help.

So I removed the cover and checked the connections. Here is a photo of the LED membrane: http://imgur.com/K2iQ6u9

I gave all the connections a good scrub with an eraser, and tried again. No dice.

Then I decided to grab my multimeter and measure the resistances across the membrane from the main board connection to the LED hookup. I couldn't get a single lead to register any change in resistance beyond the normal air. if Im getting full resistance from every lead, is the membrane bad? Can I replace it/bolt mod my ibm at the same time with this?

http://www.pckeyboard.com/page/product/MEM

Yes, you could do that, but I am unsure if there are more problems.  I'd hate for you to go through all this to discover there are more problems than just the membrane.  In your case, I would recommend Maxx from Phosphorglow.net to restore your keyboard. 

http://phosphorglow.net/

[marketfresh]

Here is a shot of the logic board: http://imgur.com/LyV7878

Maxx looks very skilled, but I would really like to see if I can troubleshoot this.

I noticed that one ribbon is very reflective and shiny, while the one on the left is rather dull: https://imgur.com/QIysh23.

[Snowdog993]

Here is a shot of the logic board: http://imgur.com/LyV7878

Maxx looks very skilled, but I would really like to see if I can troubleshoot this.

I noticed that one ribbon is very reflective and shiny, while the one on the left is rather dull: https://imgur.com/QIysh23.

This makes me wonder if it has anything to do with the membrane at all.  I really can't help you like this.  The only thing I could do is try to help you troubleshoot.  If you happen to have a second Model M keyboard that has a good controller, you could try swapping controllers and seeing if the controller is the culprit.

A bolt mod is something you do as a last resort.

Edit: This is a video Maxx made showing the process.

[Homenubbie]

Try plugging in controller without membrane and then paperclip connections to see if anything registers

[SamirD]

Unicomp also repairs boards and they can do them without a bolt mod.

I wonder if this is just a controller issue though?

[marketfresh]

Try plugging in controller without membrane and then paperclip connections to see if anything registers

This is what I have done, and I think this answers it. Here is my setup: http://imgur.com/RW10BAF

This is the first time an LED has come on EVER. Here is a GIF of when I connect the board to my pc with the blue cube: http://gfycat.com/DampThirdBream

I can't seem to connect the rest of the membrane without damaging it, but I think this points to it being the issue. Thoughts?

[Snowdog993]

I can't seem to connect the rest of the membrane without damaging it, but I think this points to it being the issue. Thoughts?

You can't connect the membranes to the controller?  Is the membrane pinched or something?  It should not ever be folded.  I have not seen a single picture of the membranes.  All I see are parts of it.  Can you align the membrane to the controller to the connectors on the controller at all?  The pins on the controller look a little out of whack.  Perhaps you need to be sure the pins are lined between on both ribbons. Be sure they line up and make contact.

I don't know what else to say.

[invariance]

I noticed that one ribbon is very reflective and shiny, while the one on the left is rather dull: https://imgur.com/QIysh23.

The shiny one is the metal trace and is the contact side of one membrane while the dull one is looking at the back side of the other membrane.  If you flip it over it should be shiny too.

Then I decided to grab my multimeter and measure the resistances across the membrane from the main board connection to the LED hookup. I couldn't get a single lead to register any change in resistance beyond the normal air.

With the above information, it depends on where you were making contact with your dmm probes; possibly on the back of the ribbon?
Even with getting some action out of the leds by using jumper wires, the original issue is still there.  We still need further pictures.

Please elaborate on the 'can't connect rest of the membrane...' also.

The leds are simply an output from the controller, they do not affect the function of the keyboard and in fact could be left disconnected.  I think you are investing too much time in the wrong area.

Make sure there isn't anything in your mobo bios in regards to the ps/2 ports that needs changing.
Something else: if you have a ps/2 port on your pc, why are you bothering with an adapter?

[marketfresh]

Then I decided to grab my multimeter and measure the resistances across the membrane from the main board connection to the LED hookup. I couldn't get a single lead to register any change in resistance beyond the normal air.

With the above information, it depends on where you were making contact with your dmm probes; possibly on the back of the ribbon?
Even with getting some action out of the leds by using jumper wires, the original issue is still there.  We still need further pictures.

I was making contact with the same side that makes contact with the logic board.

Please elaborate on the 'can't connect rest of the membrane...' also.

I was referring to this instance:  http://imgur.com/RW10BAF where I "paperclipped" the LED connection, bypassing the ribbon cable. This is the only time I have ever gotten the LEDs to register any connection and light up. This leads me to highly suspect the membrane itself is not providing a good enough connection.

I cannot connect the membrane to the logic board with this paperclip setup at the same time without damaging it.

The leds are simply an output from the controller, they do not affect the function of the keyboard and in fact could be left disconnected.  I think you are investing too much time in the wrong area.

But if the LEDs were not responding with the ribbon cable connected and without any modification by me, and now they are, doesn't that suggest the issue is with the ribbon cable?

Make sure there isn't anything in your mobo bios in regards to the ps/2 ports that needs changing.
Something else: if you have a ps/2 port on your pc, why are you bothering with an adapter?

There isn't, and also a USB connection is just easier for me to use.

[Snowdog993]

But if the LEDs were not responding with the ribbon cable connected and without any modification by me, and now they are, doesn't that suggest the issue is with the ribbon cable?

No.  There could be a controller issue, or the ribbons are not properly connected to the controller.  The LED ribbon is actually pins 9-12 on your controller.  If there is a bad ribbon there, you can easily fix that with an arduino m-m jumper.

[marketfresh]

But if the LEDs were not responding with the ribbon cable connected and without any modification by me, and now they are, doesn't that suggest the issue is with the ribbon cable?

No.  There could be a controller issue, or the ribbons are not properly connected to the controller.  The LED ribbon is actually pins 9-12 on your controller.  If there is a bad ribbon there, you can easily fix that with an arduino m-m jumper.

Well I know pins 9-12 are good, as demonstrated by my temporary rig. I find it unlikely that a freshly unboxed model M has a bad board as it has never been used, but the same could said for the ribbon I suppose.

When I go back to just using the ribbons, and fully connect everything after cleaning with an eraser, the keyboard remains as unresponsive as ever. How can it be that the ribbon/membrane is not the issue, if the board successfully powers the LED when jerry-rigged? I can't jerry-rig the keys.

[Snowdog993]

Well I know pins 9-12 are good, as demonstrated by my temporary rig. I find it unlikely that a freshly unboxed model M has a bad board as it has never been used, but the same could said for the ribbon I suppose.

When I go back to just using the ribbons, and fully connect everything after cleaning with an eraser, the keyboard remains as unresponsive as ever. How can it be that the ribbon/membrane is not the issue, if the board successfully powers the LED when jerry-rigged? I can't jerry-rig the keys.

If the controller is good, then the membrane could be bad due to some reason.  If that is the case, replacing the membrane is the way you have to go.
Good luck!