Unicomp Ultra Classic springs not buckling properly

[shibbyllama889]

I have an Unicomp Ultra Classic I got about two years ago that recently started severely malfunctioning. I used this keyboard semi-regularly for over a year, and then shelved it in its original box for about 6 months. I took it back out to use it and notice about 1/3 of the keys don't register properly.

I hear a distinct difference between working keys and non-working keys. The springs on the non-working keys do not buckle until I press very hard on bottom out. And only then does the spring give the slightest of click. The key ends up registering, but only after slamming the key harder than normal. If I press the non-working keys with normal force, you hear no click at all.

The non-working keys are scattered throughout the keyboard, though most of them are in the alphanumeric area. It seems like there are severe mechanical problems with this keyboard after it was just sitting on a shelf for awhile, and I'm pretty bummed about it. Is this the type of issue that the bolt mod is supposed to fix? Can I even do that on an Ultra Classic? I looked at a few guides and this keyboard isn't as similar to the Model M as other Unicomps are. Anybody have an idea what's going on?

[nubbinator]

Are the key caps seated properly?  If they spring isn't in them properly, they won't work properly.

[Puddsy]

How did you have it stored? Was there anything heavy on the box? Was it in a box?

BS springs don't like being depressed for long periods of time.

[shibbyllama889]

Are the key caps seated properly?  If they spring isn't in them properly, they won't work properly.

I'm quite sure they are seated properly. I've taken them out and inspected the barrel and spring, compared the broken keys to the working ones and everything looks the same. The only difference I feel is when pressing them, the spring just doesn't buckle until completely bottoming out, and only then it's a very weak buckle.

How did you have it stored? Was there anything heavy on the box? Was it in a box?

BS springs don't like being depressed for long periods of time.

I had it stored in its original box with nothing else on top of it, I'm pretty sure. At the worst it was stored vertically. There's a possibility the box was horizontal for awhile and a cat may have laid on it at some point. Definitely no long term depression though.

[fohat.digs]

I'm quite sure they are seated properly. I've taken them out and inspected the barrel and spring, compared the broken keys to the working ones and everything looks the same. The only difference I feel is when pressing them, the spring just doesn't buckle until completely bottoming out, and only then it's a very weak buckle.

"Seated" is a bit of a misnomer because we are actually referring to what is happening at the "top" of the key stem where the spring is in contact with it. There is nothing to see, only feel.

The top of the spring needs to be centered in the stem and there is a little dimple that it "seats" into.

Take out the key stems, stand the keyboard up on the front (spacebar edge) and have the springs flopping down (forward) as you carefully reinsert the key stem with the spring centered in it.

[shibbyllama889]

I'm quite sure they are seated properly. I've taken them out and inspected the barrel and spring, compared the broken keys to the working ones and everything looks the same. The only difference I feel is when pressing them, the spring just doesn't buckle until completely bottoming out, and only then it's a very weak buckle.

"Seated" is a bit of a misnomer because we are actually referring to what is happening at the "top" of the key stem where the spring is in contact with it. There is nothing to see, only feel.

The top of the spring needs to be centered in the stem and there is a little dimple that it "seats" into.

Take out the key stems, stand the keyboard up on the front (spacebar edge) and have the springs flopping down (forward) as you carefully reinsert the key stem with the spring centered in it.

Thanks for this information. I didn't know about that spot on the stem for the spring to sit. Using your method I was able to get a couple of the keys working but not all. I've tried every which was to seat the spring properly and for some keys the spring just doesn't buckle until the very bottom of the press.

It might just be my imagination, but for the malfunctioning keys, their springs appear to be shorter than those of the working keys. The springs don't quite peak out the top of the barrel like the working keys. And the feeling of the key press sure feels like the spring is too short and it isn't buckling at the correct distance.

Which leads me to some info I left out. When this first happened I took off the top face of the case and was peering around inside. Some small, flat plastic discs fell out of the case. I surehope those weren't some kind of spacer for the spring but they literally just fell out.

[E TwentyNine]

Which leads me to some info I left out. When this first happened I took off the top face of the case and was peering around inside. Some small, flat plastic discs fell out of the case. I surehope those weren't some kind of spacer for the spring but they literally just fell out.

Those are the plastic rivet ends, and losing them could potentially cause the behavior you're seeing.

The top plastic barrel plate is sandwiched together with the metal curved plate and the membrane in between. The plastic rivets are melted while everything is squeezed together. This holds the top plate on.  When the ends fall off, the plastic can separate a bit and you can get bad keys.

The fix for this is a bold mod, discussed here often.

[shibbyllama889]

Which leads me to some info I left out. When this first happened I took off the top face of the case and was peering around inside. Some small, flat plastic discs fell out of the case. I surehope those weren't some kind of spacer for the spring but they literally just fell out.

Those are the plastic rivet ends, and losing them could potentially cause the behavior you're seeing.

The top plastic barrel plate is sandwiched together with the metal curved plate and the membrane in between. The plastic rivets are melted while everything is squeezed together. This holds the top plate on.  When the ends fall off, the plastic can separate a bit and you can get bad keys.

The fix for this is a bold mod, discussed here often.

This is what I was afraid of. I'm very surprised that they just fell out like they did. I know opening the case is always a risk but I wouldn't have though it was so fragile that they could fall out by gravity. Perhaps the keyboard got dropped at some point and knocked them loose initially.

Bolt mod will be something I'll have to think about, I'm not the most handy. Thanks everyone!

[E TwentyNine]

They broke at some point and were kicking around the case until you opened it.

You can just try to repair the areas where the rivets are missing before trying a full mod.  Nothing to lose.

[fohat.digs]

Thanks for this information. I didn't know about that spot on the stem for the spring to sit.

A picture is worth a thousand words.

There are methods of replacing springs that I have not tried. What is that new one with the pop-rivet shank?