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geekhack Community => Keyboards => Topic started by: baso88 on Fri, 07 June 2013, 18:45:24
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Hi guys,
i am restoring old Olivetti M24 computer - it's one of the first 100% software compatible PC/PC-XT clones. It's interesting machine based on then-very-powerful i8086@8Mhz. It has proprietary 16bit expansion slots (backward compatible with XT-bus, but not compatible with "later" ISA bus), 16bit "hi-res" (640x400) CGA compatible graphics card and also proprietary keyboard interface. DB9 is used as keyboard connector and according to the manual you can connect classic AT-compatible keyboard (hmm shouldn't it use XT protocol, back then?) via adapter or one of Olivetti keyboards. These Olivetti KBDs uses special protocol (bi-directional like AT), provides additional keys, "slightly" different layout(s) and build-in mouse port (like on Apple keyboards ...but implementation is different of course).
I started working on restoring Olivetti KBD today, and inside i found rather interesting (to me anyway) rubber dome "mechanism", much more complicated than classic rubber dome keyboards.
Here are some photos:
Little bit filthy...
(http://i.imgur.com/gaaoCFo.jpg)
(http://i.imgur.com/3t0VvwD.jpg?1)
PCB and metal back plate:
(http://i.imgur.com/sEfpi2k.jpg)
Compared with IBM Model M 122-key terminal KBD...
(http://i.imgur.com/z5O30NG.jpg)
Disassembled:
(http://i.imgur.com/I5TSgXH.jpg)
(http://i.imgur.com/hqbszUi.jpg)
Keycaps can be easily removed by hand
(http://i.imgur.com/IFs5cA0.jpg)
Key "mechanism" ...also removable
(http://i.imgur.com/lI0PUAn.jpg)
(http://i.imgur.com/gy62EWo.jpg?1)
Parts of the mechanism:
(http://i.imgur.com/WRaAegU.jpg)
Some more details:
(http://i.imgur.com/M99bNG5.jpg)
(http://i.imgur.com/basjSXX.jpg)
(http://i.imgur.com/meiRzTp.jpg)
Keyboard conector (DB9 male) and mouse connector (female):
(http://i.imgur.com/q35ss4F.jpg)
Rubber dome:
(http://i.imgur.com/waU4GuV.jpg)
(http://i.imgur.com/2K0SdlM.jpg)
"Top" metal plate:
(http://i.imgur.com/NTaFwBa.jpg)
Top side of the PCB:
Why did they take 12V from motherboard and then use 7805 to get 5V INSIDE the keyboard? Seriously, 12V is never directly used in this keyboard... And there is 5V available on KBD connector (for classic keyboards)!... Does it need that much current, so they used higher voltage + regulator? Hmm dunno.
(http://i.imgur.com/dRg1vVF.jpg)
Waiting to be cleaned:
(http://i.imgur.com/qUC19Qr.jpg)
Tactile feedback and "click" sound is (now) somewhat inconsistent, but most of the keys are OK (much better then "modern" $5 rubber dome KB).
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Is there a membrane that you didn't include in the pictures? What makes you think this is a rubber dome board? Perhaps I can't tell the texture of the components from these pictures but they kind of remind me of hall switches.
That layout is pretty cool. That power configuration is straight bonkers though.
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the last piece (gray) should be rubber with a round carbon pill.
That, on the board is real gold. Nice quality.
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Welcome to GH, fellow Czech!
I thought M24 came with more "modern" keyboard.
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Is there a membrane that you didn't include in the pictures? What makes you think this is a rubber dome board? Perhaps I can't tell the texture of the components from these pictures but they kind of remind me of hall switches.
That layout is pretty cool. That power configuration is straight bonkers though.
Well, there is rubber membrane... each key has its own small membrane (gray X-shaped part) with conductive "pill".
the last piece (gray) should be rubber with a round carbon pill.
That, on the board is real gold. Nice quality.
;)
Welcome to GH, fellow Czech!
I thought M24 came with more "modern" keyboard.
Hi there and thanks :).
Yeah, it's not "technically" very advanced, but layout is pretty modern compared to IBM PC/XT or even original IBM AT keyboards. But there were many other variants of this keyboard with different layouts, like messy XT layout:
(http://s.sbito.it/images/97/9717738549.jpg)
Mouse port is also nice feature (i dont have original Olivetti mouse though :(), but device itself is an early iteration of what we call mouse:
(http://ru.pc-history.com/wp-content/uploads/olivetti_pele1.JPG)
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I thought the M24 was sold, perhaps with some variation, as the "AT&T 6300" in the US. While it also used a DB-9 connector for the keyboard, it looked nothing like your sample.
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Yes, you are right... Slightly modified Olivetti M24 (probably just different design, peripherals and software) was also sold as AT&T PC 6300, Xerox 6060 (USA) and LogaBax Persona 1600 (France).
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I have a German one:
http://deskthority.net/photos-videos-f8/olivetti-keyboard-2-rubberdome-t4783.html