Advice on modifying a new (old stock) IBM Model M (1390120)?

[awesomemodelm]

Hi all,

I will be soon receiving a brand new (old stock) IBM Model M (1390120) and I was wondering if anyone had any advice on:

• Care
• Modification for use via USB
• Bolt/Screw modding before necessary
• Etc...

Basically, any advice whatsoever, it would be much appreciated.

The reason I ask is that this is my 'first' IBM Model M, sure, I have used them back in the day heavily, but have not used one in years or even over a decade now and I really want to properly care for this 1390120, especially since it is such an early model IBM Model M and since it is basically untouched now for nearly 31 years!

I have a question about modifying or 'converting' the XT/AT interface of the 1390120. Since this was an early IBM Model M, it has an interesting hybrid connection setup, that being XT/AT, as opposed to the next Model M, the 1390131, which is of course AT/PS2. Is there anything in particular that needs to be taken into account or considered when interfacing to the controller on the 1390120?

In terms of 'available' converters, it seems that, through my reading the forum posts, that Soarer's converter is closed source and is now abandonware? Has anyone undertaken an effort to produce an open source uC converter variant? If the answer is no, then I might seriously consider using the test equipment resources I have and produce such an open source converter for my own use, and as well as other's of course.

Thoughts on any of the above?

Thanks!

[Ir0n]

There is a universal controller phosphorglow made but I think he's working on a new one?

There is also orihalcons cables. https://www.ebay.com/sch/orihalcon/m.ht ... pg=&_from=
He has a lot of converters that are soarer's based

If you feel like tinkering you can wire it up to a xwhatsit controller. (again can be found in orihalcons store.)

As for bolt mod no reason to do it if your rivets are still there.

[awesomemodelm]

There is a universal controller phosphorglow made but I think he's working on a new one?

There is also orihalcons cables. https://www.ebay.com/sch/orihalcon/m.ht ... pg=&_from=
He has a lot of converters that are soarer's based

If you feel like tinkering you can wire it up to a xwhatsit controller. (again can be found in orihalcons store.)

As for bolt mod no reason to do it if your rivets are still there.

Thanks for the input, I spent the last many hours thoroughly reading about phosphorglow's work on his universal controller, too bad he never released the design files.

I am thinking a good approach might be a TMK/ATMega32U4 with direct membrane connections, all mounted on a simple adafruit proto board. Once I get the keyboard and can measure everything, I could do a custom pcb, but, not much point really, unless I made a universal pcb for various Model M's that could have 'adjustable mounts' for some ATMega32U4 variant boards and for the different membrane connections through the Model M lineup.

Anyway, much to consider, I really appreciate the feedback, it definitely helped!

There is of course the temptation to just go the Teensy-LC route, the ARM route, and produce a custom implementation, lol!

[Halvar]

Also, there is an open source converter: you can configure Hasu's TMK controller to convert AT to USB.

However, you can also configure it to work as a controller and replace the Model M's original controller. What you need is basically an ATMega32U4 breakout board and some membrane connectors.

I used a Teensy 2.0++ and Adafruit's Bluefruit EZ-Key together with Hasu's software to replace the controller and convert my Model M SSK to Bluetooth a few years ago. It uses way too much power for a bluetooth keyboard (because the software isn't optimized for power consumption at all), but it works.

[awesomemodelm]

Also, there is an open source converter: you can configure Hasu's TMK controller to convert AT to USB.

However, you can also configure it to work as a controller and replace the Model M's original controller. What you need is basically an ATMega32U4 breakout board and some membrane connectors.

I used a Teensy 2.0++ and Adafruit's Bluefruit EZ-Key together with Hasu's software to replace the controller and convert my Model M SSK to Bluetooth a few years ago. It uses way too much power for a bluetootzh keyboard (because the software isn't optimized for power consumption at all), but it works.

Great point on Hasu's TMK controller having the ability to function as a converter.

Yes, this is the first approach I am thinking about taking. I was wondering if I should get the Teensy++ 2.0 or the Adafruit ATMega32U4 breakout board instead? Both seem more than up to the task.

Yea, I am going to hold off on the bluetooth, but, good to know that it might not be an 'energy efficient' approach, or, more to the point, annoying if you have to keep recharging the battery often.

[Ir0n]

The comment about bluetooth made me remember another thing

https://www.ebay.com/itm/Bluetooth-USB- ... SwZLtaHomM

[Halvar]

Yes, this is the first approach I am thinking about taking. I was wondering if I should get the Teensy++ 2.0 or the Adafruit ATMega32U4 breakout board instead? Both seem more than up to the task.

If you're going for a converter, you can also use the "Micro Pro" which is dirt cheap, or the Teensy 2.0 (without ++), which has a great bootloader that makes it very easy to upload a firmware. Also the Teensy 2.0 has been the bread-and-butter board that everyone has been using on these forums for years.

[fohat]

Before you do anything else, you should verify that you actually have to do anything at all. My understanding is that you can use a simple AT-to-PS/2 adapter or get a PS/2-SDL cable and use it as-is.

If you "just want" a programming capability, and $38 is within your budget, get one of Orihalcon's great clean slick SDL-to-USB cables.

I have bought a used 1986 Model M with no broken rivets at all, and I bought a new-in-box 1992 with nearly half of its rivets broken. There is no way to know in advance.

[seebart]

Before you do anything else, you should verify that you actually have to do anything at all.

Agreed! If all the rivets are in place I would not mod it at all. For now.

My understanding is that you can use a simple AT-to-PS/2 adapter or get a PS/2-SDL cable and use it as-is.

Correct. My 1390120 had a thick black SDL-DIN clable like my some of my Model F's came with.

[awesomemodelm]

Before you do anything else, you should verify that you actually have to do anything at all. My understanding is that you can use a simple AT-to-PS/2 adapter or get a PS/2-SDL cable and use it as-is.

If you "just want" a programming capability, and $38 is within your budget, get one of Orihalcon's great clean slick SDL-to-USB cables.

I have bought a used 1986 Model M with no broken rivets at all, and I bought a new-in-box 1992 with nearly half of its rivets broken. There is no way to know in advance.

Good points, I don't want to go crazy modifying a perfectly working keyboard, if that is the case. But, if I have to 'go in there' at all, I was figuring, why not do some pre planning, and see what I can do controller replacement or converter wise.

I am also getting the thick black SDL, new old stock, like seebart mentioned he got.

All in all, I was just figuring, IF I did end up doing some sort of custom setup, it 'might' be useful to others with Model Ms that might want to go that route. Considering I have spent a few days looking into what has already been done, there does not seem to be a 'need' in the community, in terms of custom firmware, but, perhaps a nice and easy controller replacement scheme might fall into the 'helpful' category.

Now, if I went the full on 'make a custom PCB' route, one that is made to fit the Model M, and act as a full controller replacement wherein you can load TMK or your own custom firmware, I could see that being a potential 'desire' of the community, at least it seems as such, especially considering the fact that phosphorglow did not release his design files and such. Or, it could even be a custom PCB that merely acts as a sort of 'shield' for a Teensy variant, the ribbon headers for the membrane connections, and acts as a nice form fitting mount for everything sindie the Model M. The issue with that approach is the different membrane connection schemes throughout the Model M versions.

Well, we shall see, I will think a lot more about all this, thanks for all the feedback!