Vintage Compaq Portable III Keycap Repair :-/

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20 Sep 2020, 08:05

Ermmm... for those who have Twitter-length linguistic tolerances :( skip to the YEEEEESH, GET TO THE FREAKIN' POINT, STARHAWK! text in bright red below... also, you have my sympathies. For those who prefer a bit of meaningful background, read on from here ;) Hey -- I was raised to be respectful of others. I'm tryin' here!

I have two Compaq Portable III systems, courtesy of a wonderful friend who sent them to me. One arrived nearly intact, and needed only a keyboard swap with the second to be power-up-able... however, it needs a bit of further work before it will /boot/. tl;dr, the BIOS Setup utility is not built into the BIOS ROM but rather on a floppy disk... and it configures options also not in the ROM but in a battery-backed RAM/RTC chip (Dallas Semi DS1287). I need to create the floppy (I have the image) and do a battery hack for the chip. The other system, tho, is missing parts -- most notably the drives, which are a bit weird and mount to a removable bay mechanism that is roughly analogous to the modern laptop hard drive caddy, which is unfortunately also missing. (I swapped a few chassis parts over to the more complete one as well.) I'm probably not going to try and restore this one... the drives are uhm rather odd, especially the 5.25" floppy drive. That drive is way shorter than any other such drive I've literally (not figuratively, and I know the difference!) ever seen. It's almost square!


So I'm reusing parts elsewhere. I may or may not wind up rebuilding that system with more modern parts simply to be obnoxious in coffee houses (LOL)... this is absolutely not the subject, however, of this particular thread.

Rather, I'm reusing the keyboard in a very different machine, one I'm building. I'd prefer for the moment not to get into the particular design of the system because it's an extremely unique concept -- at least as near as I can tell, there's only one example of anything close, and it's a very recent build that appeared fairly recently. I'm a bit suspicious of it TBH, since I've been thinking about this for a fairly long time (several months) and I've told very few about it, and then only recently... so I kind of wonder, given the timing. Meh :-/

But... the keyboard in question (again, a Compaq Portable III keyboard) presently doesn't work -- its cable is in absolutely horrible shape, and I rather suspect that's the only real problem with it. Unfortunately, in the process of prying it open (no screws on the external housing, only clips -- color me pleasantly surprised, indeed!), I managed to knock the "-" keycap off the numpad... oh dear :oops: I do hate being so clumsy. Photos of the aftermath of my epic fail have been attached.

I have few resources right now to fix it... I don't have either of the prongs that constituted a mounting system; both of them are somewhere on my carpet... alas, the carpet is the same color, so I'm not going to even bother trying. I have various adhesives and hand tools (a healthy stash of Dollar Tree super glue gel comes to mind first, and my battery drill and a corded Dremel that was a gift from a relative... there are others. Ask me for a full list or about specific adhesives/tools/etc, although I'll mention, as I should -- the drill and Dremel are my *only* power tools, although I have a ton of bits/etc for both...).

Advice requested!

...also, f someone wants to just send me a replacement keycap, I *should* have the ability to reimburse you for postage (don't want to get into it, but I have a super tight monthly budget, and right now my bank balance is us$1.99... and I'm just thankful it's neither zero nor negative) first thing Monday morning when a refund from Paypal (from a very necessary transaction that wound up being duplicated accidentally) finally lands. I'm in NC, USA... in-country offers only, please, strictly as a matter of economy!
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21 Sep 2020, 02:48

No suggestions...?

Again, if the post feels too long, skip to the line below the all-caps-red-text remark... sorry for the sarcasm about that, BTW -- it's me, not you ;) I'm a millennial who is not affected by the Twitterization of communication these days (TBH I have been known to read entire novels in a single sitting!) and in fact I have a theory that it's a major contributor to a lot of current societal upheaval. If you can't communicate well, or at all, and you need to, that's when Bad Things Happen.


21 Sep 2020, 04:00
This trick has previously worked for me on fixing stabilizer hooks in model m keycaps, so hopefully it will work for you too.
You probably need some needle files to enlarge the hole after the glue is set.

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21 Sep 2020, 06:39

Thx :) don't have needle files or (right now) the ability to buy 'em. Early October, probably... if I can get em at the local Walmart.

But I can be pretty clever with an Xacto knife. I can be, er, pretty clumsy (boy that's a story lol) but when I'm not being clumsy I'm not half bad.

FWIW, the switches are Keytronic foam&foil. I seem to recall that chyrosran22 (know him from eBay and then YT... sent him the IBM Model M13 he used in that video, still stinging a bit TBH because he left something out of that he'd promised... :-/ not a lot but a little bit) ripped em up for being bad when new and well worth one of the videos he has to put a warning on ;) when they're as old as this one is. I'll get a photo later of the keyboard without the key, and maybe get a few inside shots. I have to swap out the cable (going for a PS/2 cable instead, because reasons... at least it's beige!) anyways, so... probably later tonight? IDK. Energy is a fickle and questionable thing these days.

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21 Sep 2020, 08:20

@zzxx53... a few immediate thoughts from watching the video... (apologies if typos make it through, typing on phone ATM.)

I have Super Glue, the gel kind that Dollar Tree sells. I actually recommend it because of what many others might see as a flaw... where Krazy Glue brand gel really means it when they say "you got 5 seconds buddy" -- not so much this stuff. You gotta give it a good 15-30sec, and if it moves, you get to dry scrape & reapply.

That said, if you're clumsy as [FCC Fine Me Words lol] but you can naturally grab, clamp, or latch onto something with the kind of grip an unshielded US mains cable would give you... ;) even for a half minute, you get to save a TON on that stuff. The trick with Dollar Tree is in sorting out what's good and what isn't. Like those tourist trap mining places that let you pan for precious metals and stones... you just have to be able to tell what's a gem and what's just prettied-up gravel.


Don't have baking soda on hand, but I got all-purpose flour... please don't ask... I might try that, since what the baking soda is doing is simply providing structure. I'm also toying with making a paste using the flour and some Loctite brand (I think? Might be JB Weld) two-part stuff, specifically for plastics. I got it to fix a big green-n-yellow plastic garden cart... then I found out the cart was made of one of those plastics you can't glue because literally nothing sticks :(

I've also got some fairly dense pink antistatic foam from a chip eBay sent. I'm thinking if I make like a long square block (i.e., square on the top and bottom, but rectangular from the side) I can pour it full of Super Glue and stick it in the cap... when the glue hardens it'll pretty well be a plastic peg. I've done that with 3M foam tape when it wants to be super rude and misbehave and just fall right off... works great, and the tape hardens like sidewalk concrete.

In fact, I'm gonna try the foam thing first. I'll let you folks know how it goes :)

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21 Sep 2020, 09:53

Ohhh dear... :-/

These are specifically Keytronic *tactile* keyswitches, the ones with the little rubber boot around them for the pop-back springiness. I seem to have lost the boot, unfortunately, and the switch's foam-and-foil bits are starting to fall apart...

...and the switch seems to want to stay down and not get up :( I think it needs a bit more than super glue at this point... like those pills they have on late night TV for midlife crisis dudes who just bought a Miata but haven't quite left on the road trip yet :P

I know chyrosran22 has a Twitter account, I think he muted me on there after I whined a bit at him about the omission from that one video (and maybe a few other things)... but I'mma try. He's on here too right? If someone can poke him for me, I'd appreciate that, see if maybe we can work something out. Sure, I'm a little sore, as mentioned, but we all goof up a little bit every now and again. I've done far worse myself, and I could stand to get over it anyways.

I'm here if he wants to come chat... I don't bite and I try not to bark :)


21 Sep 2020, 15:27

Baking soda is not just providing structure. Cyanoacrylates are self-polymerizing. Crazy glue adds sulfonic acid, which inhibits that. The acid reacts with moisture in the air to (relatively) slowly break down and so cure the adhesive. Baking soda neutralizes the acid almost immediately, so the same process happens much more rapidly.

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21 Sep 2020, 21:28

Iiiiinteresting...! I kind of wondered TBH.

No response yet from Chyrosran... predictably...

Anyone else can help? It needs a replacement boot and the foam + foil/plastic disc assembly stuck back together, at this point :-/

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