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IBM AT ANSI Mod -- Are XT and AT Rocker-Springs Identical?

Posted: 05 May 2014, 02:27
by Hypersphere
I will soon be getting an IBM AT keyboard, and I would like to do an ANSI mod, which I understand involves simply moving some rocker-spring (hammer-spring) assemblies to different barrels. However, I have some other modifications in mind that will involve adding some additional rocker-spring assemblies. Unfortunately, although I have some extra XT rocker-springs, I do not have any extras from an AT. Therefore, my main question at this point is, are AT and XT rocker-spring assemblies identical, or will I need to get some AT rocker-springs? Thanks.

Posted: 05 May 2014, 22:11
by JBert
I can't remember if they're 100% identical, but I believe they are very similar.

What you need to be most aware of is the difference in barrels - one of them has an extra "pin" protruding through the front plate while the other has a lip connected to the barrel.

Posted: 05 May 2014, 22:17
by Muirium
Interesting… have you got some pictures? I wonder which one the Kishsaver is more like.

Posted: 05 May 2014, 22:33
by JBert
Compare the barrels of the PC portable:

Image

with the barrels of a later model F 122:

Image

See linked threads for the source of the images.

Posted: 05 May 2014, 22:48
by Halvar
I dont have a Model F, but it seems to me that the springs are different, see this post on GH:

http://geekhack.org/index.php?topic=578 ... msg1318050

Posted: 06 May 2014, 00:26
by Muirium
I was just replacing a couple of springs in my Kishsaver the other day, and this picture Halvar linked is indeed accurate:

Image

Good news for me: a Model M spring works on a Model F flip plate! I just chopsticked it right on in. The only difference I can tell from other keys is in the pitch of the twang. Nothing horrible.

Posted: 06 May 2014, 10:44
by JBert
Halvar wrote:I dont have a Model F, but it seems to me that the springs are different, see this post on GH:

http://geekhack.org/index.php?topic=578 ... msg1318050
That's model F vs model M.

What rjrich asked was if the springs between model F XT and AT got changed, which I can't really prove.

Posted: 06 May 2014, 17:31
by Hypersphere
Thanks for the replies. Although I would like to get the extra springs and hammers that I might need before tearing down the boards for refurbishing/modding, I hope to have the AT by next week. As soon as I can find the time, I will tear down both an XT and the AT to see what differences, if any exist, between the spring-hammer assemblies of each.

Posted: 06 May 2014, 20:58
by Parak
Barrels are not compatible (but can be made to if you don't mind some extra wobble), and the spring/flippy are compatible. There were a few different flippy designs for capsense buckling spring boards with minor differences (unknown as to why), but they are all interchangeable.

Posted: 01 Jun 2014, 01:45
by Hypersphere
What about compatibility between XT and F-122 barrels and rocker-spring assemblies?

I now have several XTs, some of which could serve as donors. I have two F-122s, which I am interested in restoring and modifying -- hoping I can use parts from XTs for the F-122 restorations/modifications. Of course, I can answer my own question soon, but I have not yet opened up the F-122s.

Thanks.