deskthority

I recently acquired another IBM 5100 in hopes that this one would work with minor restoration but it's a far bigger project than I had hoped. The keyboard needs work for this one so I am taking some pics along the way and hope to get some advise from anyone who may have taken apart a beam spring before.

I would like to dismantle and clean each key switch but I only have a very small number that came apart completely because of stuck key caps. I'd like to safely take apart the rest if anyone has any techniques. Anyway, here are some pics.

The project computer:

The best way to remove a beamspring cap is to use wire or cotton under the cap and firmly put pressure on it dont pull too hard constant pressure and give is a very slight wiggle top to bottom when pulling.

andrewjoy wrote: The best way to remove a beam spring cap is to use wire or cotton under the cap and firmly put pressure on it don't pull too hard constant pressure and give is a very slight wiggle top to bottom when pulling.

Thanks andrewjoy. Key caps are off. I'm trying to remove the metal inserts in the plungers so I can dismantle each key switch individually to clean them up.

The key caps are in this pic that I forgot to add. A normal key puller worked fine and none of them broke.

The wire types are OK for a beamspring but the plastic ones will or at least have a high change to damage the cap.

Weird - an IBM 5100 with grey keycaps. Of course, the prototype SCAMP had grey keycaps and the 5110 had them too. Judging by the chip dates, it looks like early 1975, so it's possible that they're grey because it's a very early 5100. (make sure to say that in an eBay listing when you sell it ) You got the APL verison. Nice.

The PCB is unlike any beam spring PCB I've seen. Obviously, the controller is integrated, but even the pad arrangement is weird.

Mr_a500,

You know your stuff. The serial number of this BASIC/APL IBM 5100 is 10575. I am assuming they started at 10000 so this would be number the 575th 5100 made. My other BASIC only 5100 is serial number 12452. Since both Model numbers are stated simply as 5100, I am assuming the BASIC, APL and BASIC/APL variations were not numbered with different serial number runs.

What is also peculiar about this keyboard is the double row legends on the key cap side (or face). The top row has BASIC keywords but the bottom row has additional APL symbols. All other APL keyboards, including grey keyboards on the 5110 series, have only one row that have BASIC keywords only.

The only other picture I have seen that is similar to this one at http://www.old-computers.com/museum/com ... st=1&c=795 and the picture file name is IBM_5100_System_1. I am suspecting that this picture is from stock footage for media release. I have never heard of the "System 1" model designation.



If the serial numbers start at 10000 and this is 10575 and the serial numbers are shared with BASIC model 5100s that outnumber the BASIC/APL systems than, yes, this is very early.