advertisement


Vintage computer fun

52729294207_054f932e68_b.jpg


A rather blurry picture, but hopefully it still shows up as being a bit cleaner! The head is moving smoothly and tracking properly in the white plastic spiral-grooved wheel now. It will never be a pretty drive, I’ve sacrificed the really tatty corroded Apple label on the front as part of the cleaning process, and the metal case is very tatty, but it now stands a pretty decent chance of working. Useful as a spare, plus, assuming both actually work, it will enable copying disks.
 
Anyone have experience with the Psion II XP pocket computer from the 80s? There is one for sale locally and I have a completely irrational urge to buy it and use it to do a few things my iPhone already does much faster and better.


Works and look great, but doesn't have the patch cord.
 
I remember my dad having one of these...

07tR3TiJXgXqLdjh1lEsUyY.fit_lim.size_1050x578.v1569508224.jpg


....and this beasty, which was specially programmed to handle compound interest etc.

s-l500.jpg


You could re-programme it yourself in Basic to do all sorts of complex operations, quite a nifty thing for the time.

He also had a more advanced folding jobby with the yellow hued display, can't seem to find an image that matches my memory of it....
 
not really what i would call vintage - also found in a drawer - a tiny handheld Sony Vaio PC - running vista - attached to the network and hey it still works. Windows update tells me it last checked for updates in 2009

20230315_090945 by uh_simon, on Flickr
 
  • Like
Reactions: MJS
52749274550_4b64f00e26_b.jpg


Hmmm, I think I might have found out why the Apple II keyboard wasn’t working! The leg wasn’t in the socket either! I suspected it was the problem as these sadly bespoke to Apple and therefore valuable keyboard controller chips have a habit of going bad causing part/total loss of keyboard functionality, so I’d already ordered a replacement IC from Joe’s Computer Museum in America. I only pulled the original out of the socket today to fit it as the replacement turned up. A real D’oh!/WTF?! moment!

The Apple II is still very ill, but I am at least getting something for every keypress now. This is a big step forward as if the keyboard was bad it effectively becomes a spares machine. There is still obviously a RAM or logic issue elsewhere as there is a load of glitching and random crap on the screen, key presses are not consistent with a lot of repeating and some random characters, flashing attributes etc. Exactly the sort of thing one expects with bad ram or logic. My suspicion is the keyboard itself is fine and I’ll take that as a win. I do have a full three banks of allegedly NOS Texas Instruments RAM waiting, but I’m going to finish building my chip tester (as seen behind in the pic) before moving forwards on that.
 
I decided to keep going. I’d thoroughly checked the installed RAM was getting the correct voltages so figured out installing new chips wouldn’t damage them even if it made no progress. It worked. The glitching went once the initial 16k bank was replaced so I chucked the other two in too. It now has 48k, as it should.

It will even load Pac-Man (I bought some games floppies), which is IMHO the definition of a working computer:

52749467948_0bf8d016dd_b.jpg


I still have much work to do. The keyboard is inconsistent; sometimes keys don’t register, other times they repeat, though none are actually dead. That may be a logic or timing thing, or it may be a dirty contact thing (this Apple really was filthy). I’ll work through the logic chips once I’ve finished building the chip tester, failing that I’ll take a deep-dive inside the keyboard and clean all the electrical contacts.

PS Pleased to see the disc drive I stripped right down works fine!
 
52751494793_4341b38387_b.jpg


Pre-exploded Rifa X2 cap replaced. The Apple II PSU is remarkably similar to the BBC Micro in many ways. My knowledge of electronics history is very limited, but I suspect it was one of the first switch-mode PSUs. It is an absolute PITA to get apart. I’m not doing a full recap on this as other than the Rifa it seems fine. Absolutely no sign of bulging, leaks, and whilst I was getting a load of erroneous in-circuit capacitance readings with my Peak tester ESR was very low giving the ‘double-beep’ of happiness everywhere.

I also replaced all the 104 ceramic caps on the keyboard controller board as I’d read that can be a cause of key repeats. Sadly no difference. I’m pretty sure the 555 timing chip is ok, but I may replace it just to rule it out. The ‘Rept’ key functions exactly as expected, which I think suggests the 555 is ok. It looks like I’ll have to strip the keyboard right down to board level, which is really not what I wanted to do as Apple II keyboards are notoriously temperamental. They seem to be pretty crap compared to say the BBC where you really need to find a horribly school-abused one to have keyboard issues. Both mine are perfect. The spacebar is the biggest issue on the Apple II, it gives three or four spaces per activation around 25% of the time.
 
Apple II restoration is not going well:

52762703805_50a4b3f322_b.jpg


I’d ruled everything else out so no alternative but to have a look inside the notoriously bad keyboard. Much to my annoyance I obviously wasn’t the first one in here. If I had been there is a very good chance I could have saved it, but whoever was in previously had bent or pinched a lot of the spring plates which explains why it didn’t function properly.

52762787528_1086ec500b_b.jpg


This really is an awful design, the left hand side is as it should be, though several of the right spring-plates are bent and mangled from some previous repair attempt in the past. I’ve managed to get it back together again and it is just as bad as it was previously (i.e. not really usable due to missed/repeating keystrokes etc). So annoying as it means this is just a spare parts machine now. Had someone in the distant past not gone in there I likely could have saved it just by cleaning and applying Dexoxit to the contacts.
 
After leaving it for a couple of hours and giving it another go the keyboard is certainly a lot better than it was so the cleaning and Deoxit was well worth doing. I’ve managed to type ‘The quick brown fox jumps over the lazy dog’ several times without error, not even the multiple spaces that was such a problem before. The fact it is a bit of a lash-up will trigger me (I’m hopelessly obsessive about stuff), but it certainly isn’t as bad as I initially thought functionality wise. It is vastly improved by the strip and clean. I was really pleased by how well the circuit board came up, no corrosion or anything. The spring plates having been previously disturbed and bent was the issue here, that and some of the many screws had been over-tightened and don’t bite properly (I’ll fix that once I think of a way, maybe a couple of very slightly larger screws in the weakened areas). Hopefully my attempts to realign them will continue to settle-in, though I’d still like to replace the keyboard if the opportunity arises.
 
Any one here have so called Pocket Pcs the ancestor to the smart phone. I still have a couple of Fujitsu-Siemens Pocket Loox N560 with their so called trans-reflective screen
2414-left-1.jpg
 
Closest I ever got myself was Palm OS. I’ve still got a working Handspring Visor knocking around.

Back when I was an IT manager I was responsible for a fair few Toshiba Librettos which were really nice tiny little Pentium Windows 95 sub-laptop things. Too big to fit in a pocket, too small to do anything complex due to the screen size, but great fun to play Doom in the pub. Never played with Windows CE though.
 
You must log in or register to reply here.


advertisement


Back
Top