IBM Model M Bolt Mode Problem

[hunterjwizzard]

Hey folks.

I've just finished a rather inexpert execution of an bolt mod on my IBM model M. I finally got it reassembled today and working 99%, but the + sign on the num pad is a problem. Its squishy and it sticks. I pretty much have to keep a tool handy do pry it back up because it won't come on its own.

What I have tried so far:
-swapped the num pad + & Enter key, problem stays with the slot
-pulled the 9 off from the num pad and put it in the barrel with the spring, works perfectly
-first removed the washer from the bolt underneath the key
-removed the whole damn bolt
-checked the support over and over again, everything looks clear.

But no matter how many times I take it off and re-seat it, its still mushy and sticks.

Some background on the bolt mod: the barrel plate cracked in a few places on the final re-assembly, but not anywhere near the num pad. The ; and ' keys had problems which were resolved by removing the bolt from in between them. The front of the keyboard is still "smiling" just a bit. I ended up having to omit the first row of bolts to make it fit properly, but the catch should be holding that part of the board together. I've been typing on it all day and besides that num pad + sign problem everything else appears to be working correctly.

Any ideas?

 

[eswan]

Here's a pic of mine, for what its worth.
I had to remove the bolt as well, it interfered with the balance bar. Works fine.
At a guess, maybe one of the plastic clips the bar fits in got deformed? Or maybe clean the edges of the bolt hole?

 

[hunterjwizzard]

If I install the + sign key where the Enter key goes it works just fine, so its not the key. The Enter key works perfectly and if I install it where the + sign goes it develops the same mushy/sticks problem. The bolt hole is down deep bellow where anything related to the key is and if there were any burs(there's not) they wouldn't be touching.

 

[eswan]

Might try removing the bar from the key and see how it feels? Other than that, all I can figure is the two barrels on the plate somehow aren't parallel.

 

[andy]

What happens if you put a single sized key in place of the + key? That would tell you if the problem is related to the support mechanism for the double sized key, or related to the buckling spring mechanism.

 

[hunterjwizzard]

What happens if you put a single sized key in place of the + key? That would tell you if the problem is related to the support mechanism for the double sized key, or related to the buckling spring mechanism.

-pulled the 9 off from the num pad and put it in the barrel with the spring, works perfectly

If I put a normal-sized key in there it works perfectly.

 

[MicroCoreLabs]

is the spring deformed in any way?
does the plate move freely on the motherboard?
is the spring fully seated on the boss on the plate?
have any/many of the plastic fasteners holding the metal bottom of the keyboard internals broken off?

 

[hunterjwizzard]

is the spring deformed in any way? - no, works perfectly if a single-spaces key is pit in that barrel
does the plate move freely on the motherboard? - not sure what this means but the plastic barrel is attached to the metal backplate by about 50+ bolts
is the spring fully seated on the boss on the plate? - it appears to be, yes. A normal sized key placed in that barrel works perfectly
have any/many of the plastic fasteners holding the metal bottom of the keyboard internals broken off? - this was a bolt mod so all of them? The mod involves removing all the plastic fasteners and replacing them with metal bolts.