[GreenKeys] Model 33 keyboard spring issue

[Jones, Douglas W]

I noticed that the CR and LF keys on my 33, and also the =- key were getting sticky.  That is, when you pressed one of them down, it stayed down and didn't spring back up.  Pressing any other key would pop it up, but obviously, something was wrong with the springs that push these keys back.

There's a big leaf spring assembly on the bottom of the 33 keyboard, all stamped out of a single bit of blued spring steel, with one finger to push up on each key.  While I had the TU out to fix the problem with the end-of-line bell, I took the time to lift the keyboard and see what the problem was.

It turns out that, every time you re-install the TU, there's a risk that the plastic paddle that engages with the "here-is" key will scrape sideways over the spring assembly while all your attention is on engaging the H plate that links the unversal lever to the transmitter distributer.  As it scrapes sideways, it can push the ends of the springs off of the bottoms of the key levers.

So, after you've installed the TU, if you find that CR, =- or LF are sticking down, what do you do?

Solution 1:  Take out the TU and possibly even the UCC so you can pull the keyboard and then use your fingernails to pop the springs back into position, then reinstall the TU, with the risk that you'll brush the springs out of place again.  Repeat until successful.

Solution 2:  Fortunately, the 3 keys that are at greatest risk of having their springs brushed to the side so they stick down can be fixed from above.  Look down into the space between the back of the keyboard and the front of the TU, and you'll find a cutout in the back-plate of the keyboard that lets you see 3 holes in the keyboard base.  A finger from each of the 3 keylevers in question pushed down through one of these holes, and from below, the leaf springs push up on those keylevers.

If the leaf springs have been brushed to the side when you installed the TU, the result is that the spring will be caught on the side of the keylever finger instead of pushing up on the keylever.  Poke down beside the keylever with a jeweler's screwdriver, and you can dislodge the leaf spring from the side of the finger.  It'll pop immediately back into place.  Problem solved.

		Doug Jones
		jones at cs.uiowa.edu