deskthority

Part of my vintage computer hobby is to save computers and make them fully functional again. I am the one who spent (what I believe to be) a crazy sum on the IBM M15 keyboard recently. This is my first keyboard restoration so I want to make sure I am doing the right thing and I am hoping you guys/gals can let me know what is good and bad.

This M15 had a spill that corroded some of the traces on the plastic sheets that make up the buckling spring mechanism. I can clean them up but I have two questions.

1. Can I use an ohm meter to check continuity or can I use something else other than the naked eye?
2. Can I use an eraser to clean the contacts? I use an eraser to clean traces on circuit boards as it picks up unseen corrosion and debris so I am hoping it will work for the traces on the plastic sheets.

If cleaning with an eraser is okay, does anyone see any issues using the eraser in the problem area? There are a couple of "bridges" that I have to be careful of but I can be gentle.

I'll also have to figure out how to "bolt" the parts together. Someone previously tried to tape it together and it took me the better part of 45 minutes to remove the tape gently.

For those who may have fixed keyboards before, how bad does this look? I think it's fixable personally.

I haven't counted the springs yet but I will need at least one key. Hopefully some kind soul will have spares. Someone mentioned M2 parts should work?

Here are some pics:
Any help is much appreciated.

I might be parting out an M2 to save another M15. If I do this I can send some parts your way.

> 1. Can I use an ohm meter to check continuity or can I use something else other than the naked eye?

Yes. An ohm meter will work well here.

> 2. Can I use an eraser to clean the contacts? I use an eraser to clean traces on circuit boards as it picks up unseen
> corrosion and debris so I am hoping it will work for the traces on the plastic sheets.

Yes.

If you do need to make repairs I recommend silver paste.

Would you mind getting some scans (not photos - scans) of the membranes for archival purposes? The more photos you share, the more I can help. I do have two M15s here from this Monday but one is complete and will likely sell, and the other may sell but needs even more love than yours does.

(At least we know you're not b***a now. Or are you?!)

Hehe.

You can check the closed auction to see if I am b***a

So far, I did check for continuity (I though it was capactive for some reason) and yes, they are conductive. Once I knew that, I knew i could clean them with the eraser. Come out quite well actually. I found one broken trace and it wasn't even on the side that looked bad.

I wouldn't mind you keeping the parts one aside for now and if I need it, I'll let you know. I really appreciate that but let's hope I don't need it and someone else can have a project. My cable is frayed but that shouldn't be a big deal, I hope. The previous owner said the other side worked fine.

I could try to scan these plastic layers tomorrow at work, if it's useful.

Here are more pics:

After a count, I need 8 buckling springs and the "0" key. XMIT, let me know if you can sell me some of these.

I will scan the layers tomorrow (I can't put this together yet to try it so I got lots of time).

Thanks.

You're "c***n" on eBay, at least to me.

Yep, these are definitely conductive. I think you'll find it straightforward to see where gaps might be in the membrane traces using a multimeter or ohmmeter. The resistance should be no more than a couple of ohms. If nothing else look for outliers to give you a hint as to where damage might be.

Most Model Ms are held together with rivets or eventually bolts. I wonder if you would need to bolt mod this one.

Once I take inventory again of my keyboards I'll know for sure what M2 parts I have available. Of my M15s (well, elecplus's which I am selling), one is complete and needs a cable, and the other has a broken adjustment mechanism and is missing several keys (including a half Space bar) and a cable.

Every b***d is a c***n on eBay. Some are even c***ts.

XMIT wrote: ↑Most Model Ms are held together with rivets or eventually bolts. I wonder if you would need to bolt mod this one.

That was my initial thought as well but I have five screws and there are six screw holes in total. There are several more holes around the plastic layers as well as the metal plate but there are "posts" that stick up that help line up the layers and metal plate. I think just the screws are required. I'll have to open up the other side tomorrow and check it.

Here's a pic of the posts with green arrows and the screw holes with red arrows. I don't think I got all the posts but you get the idea.

I just checked the DT Wiki for the M15 to see if it needed pics. I think there's an error. The article states "As with the M2, there is no metal backplate under the membrane, accounting for its flat profile and relatively light weight.". As shown in my first pic, clearly there is and the metal back plate is flat. That is considered a metal back plate, isn't it?

Yes, that's definitely a metal backing plate (defined as a plate that goes between the membranes and the rear case). Great catch - now please go fix it!

XMIT wrote: ↑Yes, that's definitely a metal backing plate (defined as a plate that goes between the membranes and the rear case). Great catch - now please go fix it!

Will do once I take some good breakdown pics to update the wiki.

XMIT wrote: ↑Once I take inventory again of my keyboards I'll know for sure what M2 parts I have available. Of my M15s (well, elecplus's which I am selling), one is complete and needs a cable, and the other has a broken adjustment mechanism and is missing several keys (including a half Space bar) and a cable.

What cables are missing? There is the main coiled cable that goes to the left half and then a cable that runs from the left side to the right.

That half-space bar missing is a killer. There's no hope of finding one is there (other than another M15)?

I'm going to see if I can locate cheap, hopefully damaged M2 because I may want to use the cable as well. As you can see from the first pic, my PS2 end is frayed. I would guess the M2 coiled cable is the same.

XMIT, if you or anyone has a broken or cheap M2 with a "0" (zero) key and a good coiled cable, I'd be happy to buy it. PM me.

The cables from the left half of the keyboard to the computer are missing. The connector cables between the two halves are still intact. I figured I might USB convert one of these (if it does not sell), and/or offer to do this for a buyer for a fee.

Since I do still have both boards I think I can get some data from the existing Space bar. If nothing else one could craft a similar shape and epoxy on buckling spring keycap "legs". I wonder if it is possible to cast it in RTV silicone and duplicate it. I kind of want to try.

I still need to sort through PMs, pull the M15s from my shed, and get some photos. Quality work takes time! Please be patient.

Quick update: I did put it together yesterday with the parts I had and I had mostly success. The arrow key on the furthest right didn't work and I put two buckling springs in the Enter key (because there were two mounting holes) and when I hit Enter, I get a "\" and and Enter most times. I'll have to check this with a single key cap to see which buckling spring should be there (the buckling springs were not installed when I got it).

I think the right arrow key doesn't work because it needs a bolt mode. I also opened up the other side side and it needs a bolt mod too so that will be my next step; ordering screws. It is a sweet keyboard.

As with any buckling spring you can try re-seating the key caps and/or re-adjusting the springs a few times to see if that helps with actuation. It is horribly tedious to do this but you can test omitting a single hammer and seeing if you can actuate that membrane contact point by poking it with a chopstick or something similar. That will tell you if the membrane is dirty or something like this.

I hope you're getting careful photos, these are rare items and we don't often get to see the insides of them.

Sorry, I should have been more clear. I re-adjusted several key caps and they worked great afterwards. The right arrow key didn't but I think it was because I wasn't careful enough when sandwiching the membranes together. That one may have moved out of the groove that the plastic part of the buckling spring fits in.

Pics will be posted. (I should have started this in the Workshop forum).

So an update because once I get going on a project, it's hard for me to stop...

I checked the Enter key that has two channels for buckling springs. I installed two springs when it should have only put in one. The right most spring is "Enter". The left most is "\" even though there is already a "\" key that works. Anyway, if I remove the extra buckling spring, I'm good.

I found the M2 x 4mm screws and 1.5mm drill bits but they were from China. Should be here by February I can't find them anywhere locally so I wait.

I found someone on eBay selling M2 key caps. Sadly, they threw out the rest of the keyboard so no buckling springs to sell. Since they weren't too expensive, I figured I'd get them. XMIT, you are welcome to some for your other keyboards so you don't have to ruin a perfectly good M2. I'll PM you.

Last thing I need is the buckling springs that are missing. I may try to get them from clickykeyboards.com along with a variety of key tops I am missing from other Model M keyboards. Seems like a good source if they have them.

The quest continues...

@snuci. Contact me after the holidays. I just recovered a couple of IBM 1395300 model M2 keyboards and many of the keys and the springs will make excellent spare parts for your model M15 restoration project.

clickykeyboards wrote: ↑@snuci. Contact me after the holidays. I just recovered a couple of IBM 1395300 model M2 keyboards and many of the keys and the springs will make excellent spare parts for your model M15 restoration project.

Terrific. It's too bad I already bought the key caps but maybe I'l buy the one I need from you anyway so I have a full set. That will give me some time to assess the other key caps I need. I will reach out after the holidays.

Thank you.

M2 and M15 are different springs than the M correct ?

snuci wrote: ↑XMIT, you are welcome to some for your other keyboards so you don't have to ruin a perfectly good M2. I'll PM you.

Got the PM, thanks! I still need to work on the two M15s and various M2s I have to figure out what needs what. Tons of people are asking me about the first one but before I sell it I want to get some good pictures, dimensions, etc. of the left Space bar so that I can 3D print and/or cast a replacement in the future if needed.

I know I'll need a cluster of arrow keys and a couple of other keys at the least.

1.5mm drill bits and metric screws should be easy to find. I happen to be walking distance from Lowe's right now so if I find them I'll pick them up and ship them to you. I'll respond by PM if this works out.

XMIT wrote: ↑

snuci wrote: ↑XMIT, you are welcome to some for your other keyboards so you don't have to ruin a perfectly good M2. I'll PM you.

Whoops, I said "keyboard" but you knew that I meant key caps.

XMIT wrote: ↑Got the PM, thanks! I still need to work on the two M2s I have to figure out what needs what.

You said "M2" but I know what you meant (you meant M15).

XMIT wrote: ↑1.5mm drill bits and metric screws should be easy to find. I happen to be walking distance from Lowe's right now so if I find them I'll pick them up and ship them to you. I'll respond by PM if this works out.

I appreciate this but I can wait. They say February but it might be sooner. Home Depot, Lowes and our own Canadian Tire and Home Hardware here don't have anything that small and the likelyhood of finding anything in stainless steel is even less.

No worries. I updated my post to clarify - in fact I meant both:

I still need to work on the two M15s and various M2s I have to figure out what needs what.

snuci wrote: ↑The right most spring is "Enter". The left most is "\" even though there is already a "\" key that works. Anyway, if I remove the extra buckling spring, I'm good.

Which means the matrix and controller also supports ISO layouts. Got an extra spot underneath the left hand switch as well?

Louis wrote: ↑

snuci wrote: ↑The right most spring is "Enter". The left most is "\" even though there is already a "\" key that works. Anyway, if I remove the extra buckling spring, I'm good.

Which means the matrix and controller also supports ISO layouts. Got an extra spot underneath the left hand switch as well?

I do recall one of the keys has an empty spot for a buckling spring. In the ISO layout, what key would it be in the left hand side?

Here's an update on my M15 repair. I'm happy to say that it is completely restored with a screw mod on one side. I had assumed that the screws needed to be added to all posts but after opening the good side for pictures, it actually uses clips on a small number of posts.

One note of thanks. I have to thank @clickykeyboards at http://clickykeyboards.com for searching and finding the exact match parts for me. If you need IBM Model M parts, he's the guy.

Pics will help explain:

Final pics with it all cleaned up. I am missing one foot on the bottom but hope to find it and the matching numeric keypad some day to complete the set.

Great work snuci! How does it feel? Will you do the same screw mod to the other side for more uniformity?

scottc wrote: ↑Great work snuci! How does it feel? Will you do the same screw mod to the other side for more uniformity?

Thank you. I contemplated it but there is absolutely nothing wrong with that side and as a preservationist, I will leave it as is so that I know what it was like originally. Technically, it is "uneven" in it's repair construction but if I could have found the original clips, I would have preferred to restore it that way to keep it original. There's no hope I would have found those clips.

I'm glad you got this together with the parts you needed! I do still need to tear into an M2. I'm glad clickykeyboards was able to get you the parts you needed.

Great looking restoration project. Must feel great to have it completed. Nice work and thanks for sharing the log.