Unicomp Ultra Classic Bolt Mod -- No Spring Buckling Afterwards

[shibbyllama889]

Awhile ago my Unicomp Ultra Classic started having many, clustered unresponsive keys. Long story short, a bunch of my plastic rivets were falling out for whatever reason. The board was out of warranty by this point and Unicomp wanted $30 plus shipping to repair it (ended up coming close to the price of a new board). I figured I'd look into doing a bolt mod on it since I had nothing to lose.

Now, I'm not a very handy person and I don't have a lot of tools available. I mostly followed Ripster's Imgur guide and these two guides:
http://forums.overclockers.com.au/showthread.php?t=1024488
https://geekhack.org/index.php?topic=62226.0 (I ordered the nuts and bolts from this guide for the mod)

My method was using a chisel to pop the rivet ends from the backplate, flush cutters to get a clean, level stem, and a soldering iron to make little divots for my drill. Nearly all of the rivet ends were already broken from the backplate, so that was easy. However, my cutter was really dull and just would not cut the stems cleanly, leaving jagged stems. I *might* have knicked some crescent tabs with the cutters as well. So I tried carefully sanding down the jagged parts of the stems manually with sandpaper. This didn't really work that well, and I ended up trying to make up for it with really precise soldering iron divots.

So I get my drilling done (going very slowly and carefully), screw in the bolts, put the hammers back in, assemble the sandwich back together, and tighten on the nuts. I had about 2 threads showing on each bolt when all was said and done. It felt like everything went really well at the end since everything lined up, though it did require strategic tightening of the nuts so that all the bolts fit through the holes in backplate.

I go to put the keycaps back on and literally not a single key is clicking. They are all just dull thuds since the spring isn't buckling. I thought maybe that I over-tightened, so I loosened the nuts in one area of the board and tried the switches--nothing, same results.

So, do you think that I screwed things up by messing up some of the crescent tabs? Did I put the hammers back in badly? I honestly did this part quickly because they seemed to go in so easily. Did I over tighten the board? Maybe I should get rid of the nuts altogether? It just seems odd that literally no switch is working at all. I didn't think I screwed things up THAT badly.

Thanks for any feedback since I really miss the feel of buckling springs.

[SpaceGhost]

When you put the keystems back in, did you tip the board up at the front so the springs would flop back and touch the 12 o'clock position in each of their barrels while inserting and pressing down each keystem to click into place? This is necessary to properly engage the spring at the top inside the keystem.

[fohat.digs]

I am guessing that the pivot plates are out of their tracks.

You named almost all of the things that I don't do: I use a sharp(er the better) chisel or chisel tip Xacto knife to cut the rivet heads and clean up the tops of the posts, use a tiny spherical burr tip to make starter divots, drill carefully, and use a fresh chisel tip Xacto to clean up the post tops, again, always trying to keep them as long as possible.

The unfortunate part is that you have to take the whole thing completely apart every time. Expect at least 3 iterations on your first job, and don't fret if it takes twice that.

[SpaceGhost]

Another thing to check:

Before you put the keystems back in, it's a good idea to grasp the keyboard along the front edge and tip it up and then back down to see if all the springs flop freely backward and forward, touching the 12 o'clock position in the barrels when you tip it up, then flopping back down close to or touching the 6 o'clock position when you tip it back down. If they don't flop back and forth freely, it usually means the nuts are tightened too much, "choking" the pivot plates. In that case, back off the tightening torque a tiny bit at a time until they do flop freely.

[SpaceGhost]

I am guessing that the pivot plates are out of their tracks.

You named almost all of the things that I don't do: I use a sharp(er the better) chisel or chisel tip Xacto knife to cut the rivet heads and clean up the tops of the posts, use a tiny spherical burr tip to make starter divots, drill carefully, and use a fresh chisel tip Xacto to clean up the post tops, again, always trying to keep them as long as possible.

The unfortunate part is that you have to take the whole thing completely apart every time. Expect at least 3 iterations on your first job, and don't fret if it takes twice that.

Of course, the fact that none of the keys click would mean every pivot plate was somehow out-of-place and wedged under the barrel frame -- or some combination of wedged pivot plates and some other cause for others not clicking.

[shibbyllama889]

I am guessing that the pivot plates are out of their tracks.

You named almost all of the things that I don't do: I use a sharp(er the better) chisel or chisel tip Xacto knife to cut the rivet heads and clean up the tops of the posts, use a tiny spherical burr tip to make starter divots, drill carefully, and use a fresh chisel tip Xacto to clean up the post tops, again, always trying to keep them as long as possible.

The unfortunate part is that you have to take the whole thing completely apart every time. Expect at least 3 iterations on your first job, and don't fret if it takes twice that.

Yeah I don't have any kind of dremel tool and I guess I didn't think my cutters were unusually dull, so I kind of gave up on the idea of simply cutting the posts. I also didn't realize the idea was keeping them as long as possible. Unfortunately about 90% of my rivet heads came off "naturally" and were pretty gnarly instead of cleanly cut by a chisel.

I will take it apart and look closer at the pivot plates, hopefully it's something relating to those since I can't undo my drilling.

Another thing to check:

Before you put the keystems back in, it's a good idea to grasp the keyboard along the front edge and tip it up and then back down to see if all the springs flop freely backward and forward, touching the 12 o'clock position in the barrels when you tip it up, then flopping back down close to or touching the 6 o'clock position when you tip it back down. If they don't flop back and forth freely, it usually means the nuts are tightened too much, "choking" the pivot plates. In that case, back off the tightening torque a tiny bit at a time until they do flop freely.

Hmm this is good advice, thanks. I think I remember not all of the springs flopping back and forth freely. I didn't think that was right but was honestly too exhausted at that point to take it all apart again. Although, it would've only been a handful that were choked, while most were flopping freely. But I'll look at that more closely. Do the pivot plates and springs need to be re-inserted specially? They seemed to just fit in the barrel plate assembly quite easily.

When you put the keystems back in, did you tip the board up at the front so the springs would flop back and touch the 12 o'clock position in each of their barrels while inserting and pressing down each keystem to click into place? This is necessary to properly engage the spring at the top inside the keystem.

This was the first thing I tried, many times. I'm fairly sure the springs are sitting correctly in the keystems.

[SpaceGhost]

I don't think the spring/pivot-plate assemblies need to be re-inserted in a special way, unless you somehow put them in rotated 180 degrees. Even if the springs are properly inserted into the barrels, if their pivot plates are rotated 180 degrees, they would not flip properly (nor actuate) and there most likely would not be any buckling or click.

The fact that *none* of them click is a very big clue as to what's wrong. Whatever it is, whatever is causing this is most likely common to all of them.

[fohat.digs]

My advice to any potential Model M bolt-modder is to get over the hump of thinking that "I will be willing to do anything except take it completely apart and do it again"

It is like re-booting your computer - that is the first and most straightforward thing to do and most often what works.

Last, you were careful to put the sheets back correctly, right? The rubber sheet ("blanket") rests against the metal plate. If you do not have the frame on a good stand, you cannot put it together without jiggling something.

PS - I have heard of people trying to use tape to pick up entire rows of pivot plates at once which seems totally stupid to me and a waste of time. If you did that, there is not tape residue is there? That would ruin everything.

[SpaceGhost]

The rubber sheet ("blanket") rests against the metal plate. If you do not have the frame on a good stand, you cannot put it together without jiggling something.

Actually the rubber sheet rests against the back of the barrel frame, between the pivot plates and the top membrane layer. I think that's what you meant, right?

[SpaceGhost]

If the pivot plates were inserted correctly, and the keystems re-installed correctly, the next thing I would try before complete disassembly is to tighten the nuts more and see if that helps. It's possible they are not tight enough to fully clamp the layers together. They need to be lightly clamped together, but with no gaps.