Model F enter key swap - big-ass on an F122

[ed_avis]

I use a 122-key IBM Model F terminal keyboard with Soarer's converter.  It has a tall, almost rectangular Enter key (ISO layout).  Nestled in the crook of the Enter key is an ordinary square key which doesn't do anything -- at least not with the converter I am using.  I will call this the 'useless key' (TM).

I would like to swap the Enter key and the useless key for a 'big-ass' Enter key taken from a PC-AT Model F keyboard.  If this were a Model M I would just get to work popping off the keys and seeing what fits.  But I know that the Fs can be a bit more tricky to put back together, and there may be extra weirdness associated with the Enter key that I don't know about yet.  (I know that the square keys are OK to remove and put back, although compared to the M it is a little harder to get the spring back in the right place.)

Can I use a lever to pop off the Enter key on my F122 and then safely put it back afterwards?

Will I be able to use the big-ass Enter from the PC-AT keyboard instead?  I might have to remove the spring from the keywell of the useless key; is that something that can be done without opening the case, and can the spring be put back afterwards?

The spare PC-AT Enter key, which I recently bought online, came with an extra spring.  Is there a particular reason why on Model Fs each key would have its own particular spring, or can I just keep using the existing spring when I swap the keys?

Having messed up my own PC-AT board by levering off the spacebar (just as I would safely do on a Model M) and being unable to put it back easily, I would like to get some advice before I start messing around with the F122.  Thanks in advance.

[chyros]

You can take any of the caps off a F122 - unlike the anchored spacebar of the F XT and F AT, these keys are all just put on in the normal way. To put them back on, just tilt the keyboard backwards.

In order to put on a BAE, you'll probably need one from an F AT, including the stabiliser peg. Can't recall if the F AT BAE has just an empty barrel jacket on the key position in use on the F122.

[ed_avis]

Thanks.  The Enter key does indeed pop off.  It has a stabilizer with two tabs, so putting it back is a little bit tricky, but not impossible.  (I did it by first putting the Enter key back with its spring in the right place, tipping the keyboard back as you say, and fixing up the stabilizer afterwards by popping the Enter key again but not removing it entirely from the keyboard.  To check the stabilizer was in place I removed the two nearby keys, the useless key and the ] key.)

The big-ass Enter from the PC-AT has a 'hole' or empty barrel jacket at the top.  Its middle position has the normal plastic hollow peg that the spring goes inside.  But on the left side of the Enter key, the part that will take the place of the useless key on my keyboard, there is a solid peg.  So to use the big-ass Enter unmodified I don't just need to pop off the useless key, but also remove its spring.  To do that, I would have to open the keyboard, right?

Since this is my main and only keyboard at work I won't do that now, though I may have a spare F122 somewhere which I could make use of for experiments.

I note that on a modern UK-layout keyboard the key nestled beside Enter is for # and ~.  I might find out if there is a way to reprogram the converter to bind it.  (I have one of the DIN-to-USB cables with the converter built in, and I think it uses some chip other than an Teensy, but there may still be a way to load new firmware.)

[fohat.digs]

I think that you are going to have to open it up.

Currently I don't have any AT bigass Enters because I sold the 2 that I had laying around. I always convert to ANSI so I have no use for them.

There are 2 different stabilizer scenarios for BAE:  wires and tabs (these work like Model M but F wires are much thinner diameter) and there is also a way with a peg and sleeve inserted into the barrel - but it is square rather than round and does not interchange with the standard type.

I have never tired to pull a spring while leaving the pivot plate in place down below, but I am guessing that it would not work because gravity would keep it in the down position.

[ed_avis]

The big-ass Enter I have has a square peg at the left (where the useless key currently is) but also has a wire stabilizer the same as the F122's Enter key.  It appears that the square peg would fit in the barrel if I removed the spring; it wouldn't do much to stabilize since there isn't the matching sleeve in the barrel, but it would probably be enough.

Anyway, I'm going to leave it for now and keep the spare Enter in reserve.  Thanks for your help.

[fohat.digs]

The big-ass Enter I have has a square peg at the left (where the useless key currently is) but also has a wire stabilizer the same as the F122's Enter key.  It appears that the square peg would fit in the barrel if I removed the spring; it wouldn't do much to stabilize since there isn't the matching sleeve in the barrel, but it would probably be enough.

I don't think that a stabilizer would do anything without its corresponding socket, but if there is a wire (vertical along the right side?) it would probably help on anything except for presses on the lower left leg (near the "useless" location).

The pivot plates ("feet") are usually held in the "up" position and the buckling of the spring temporarily rocks them downward, making your contact. If you pull the spring without removing the pivot plate, my guess is that it will flop down and stay in the "on" position.

[jeb]

The pivot plates ("feet") are usually held in the "up" position and the buckling of the spring temporarily rocks them downward, making your contact. If you pull the spring without removing the pivot plate, my guess is that it will flop down and stay in the "on" position.

I have observed a key with a flipper and no spring on a spare board; it seems to activate intermittently, which is to say, not all the time, but enough that it'd be a problem. It probably depends on where exactly the flipper is situated and whatever movement it experiences. It should be possible to just deactivate it in a converter or controller, though the repeated and possibly constant extra key press could interfere somewhat with the normal functioning.