IZOT - Bulgarian Military Keyboard

[rsbseb]

Finally had a little time this evening to tear into the Bulgarian Military Keyboard by IZOT I picked up a few months ago. There are no labels on the exterior of the case and no evidence there ever was. Overall it’s a heavy keyboard and weighs in at 6lbs 10oz compared to my IBM model M at 6lbs 9oz. I like the profile better than the IBM. I also like the green and black color scheme. The key caps are spherical and engraved. The engraving is fairly deep and can be felt when typing. The caps are also a little bit squarish and don’t feel all that good. The switches are however very nice liner magnetic reed switches. There are three different types. All but one has angled stems. Taking the case apart was a bit of a challenge all the screws were over torqued and seized, several broke and will need to be drilled out for proper reassembly.

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The case consists of three pieces that are quite heavy duty. The bottom section holds the PCB, solenoid, strain relief for the cable, and heavy rubber feet. All the screws are slotted. The top section is assembled from two parts, the main housing and a plate that frames the keys. The center plate can be replaced for different configurations. Except for the solenoid and cable clamp there are brass inserts glued in for mounting. I’m not sure what type of connector the cable has, I’ve never seen one before.

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Everything inside was pretty clean and all the switches work perfectly. All the keys on the numpad have a heavier spring except the red one and the enter key has a strait stem instead of angled. All the heavier sprung switches have a black mark on the top (even the ones with the black housings) The switch with the strait stem has a red mark on top.

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The PCB has 5 LED’s and the controller is integrated across the top half. The switches are screwed down for assembly and not removable without de-soldering the leads. The top half of the switch housings are spot welded to the lower half and not removable without drilling them out so I won’t be taking them apart for the time being. The PCB itself has had the mounting holes enlarged manually to line up with the inserts. Other than that the overall build quality is very good. The spacebar has metal inserts for the stabilizer, it is the only stabilized key on the entire keyboard. The stabilizer mounts on the PCB are designed to accommodate a larger spacebar. I found two sets of numbers that might be date related one is 5-86 the other is 2-81 so I’m not sure of it’s actual age but lean towards the 86 date since it is stamped in ink.

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[rsbseb]

Some more pics.

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Ah,the BS key...

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Here is what?

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I have no idea on this one...

izotx.jpg (74.79 KiB) Viewed 13103 times

[Chyros]

Very nice keyboard! Never seen switches that've been SCREWED in before... And it dwarfs a battleship!

I'm very surprised it weighs "only" 3 kg tbh. It looks like it would be over 4 Oo .

[andrewjoy]

That is nice , but quite strange. The construction methods are very high quality in some places ( screwed in switches, the connector being very expensive looking) to poor quality ( like LEDs just flapping about resistors sitting off the board etc.

The brown ICs are interesting , never seen that before, usually military stuff is all ceramic ICs

[rsbseb]

You have to keep in mind that this is a piece of early 80's soviet technology. It's obvious that a lot recycled materials have been used. I'm curios as to why it has line feed and carriage return keys, and what the where is and circled x keys are for. The switches are really very nice and in practice would likely become my favorite. The LED's are very secure once they are seated into the cover. I haven't looked them up but I'm sure the chips are a clone of a common IC .

[andrewjoy]

I had a quick look for the strange brown ICs, They are ROMs 226 "słów czterobitowych" witch i am guessing is 256k.

I think its pin compatible with the 63s140

http://www.datasheetarchive.com/dl/Scan ... 104157.pdf

[rsbseb]

I just realized during reassembly that the holes for the cable mount are brass inserts as well. The center plate in the cover is metal, keyboard is built like a tank

[flabbergast]

... "słów czterobitowych"

This literally means "four-bit words" in Polish.

[andrewjoy]

so its a 4bit rom ( as in it talks in 4 bits) but with 256k if i am understanding it ?

[flabbergast]

I guess I found the same forum as you The way I understand that sentence is that it's really 256 x 4bits = 128 bytes. (Not that I really speak Polish, but close enough.) Given how old it is, it's quite a good size.

EDIT: You should search for "KR556RT4" - you know "P" in Cyrillic is Latin "R".

[andrewjoy]

Ahh yeh , all them silly alphabets screw you sometimes!

I mean you would think Russia only switched to the Gregorian calendar in the 20th century...... oh wait.

[terrycherry]

Strange and rare switch I never seen before. What is feel like? Could you typing it for video?
Hope to see you assemble the switch.

[rsbseb]

I am not much of a typist but could probably get my wife to type out a few lines for a vid. I don't plan on opening any switches for a while but when I do I will share more pictures for sure.

As for the switches they are linear with about 4.5mm travel. The number pad has stiffer springs than the rest of the keyboard and are a little bit to stiff for my liking but the others feel very nice in my opinion

[Muirium]

They strike me externally as, if not clones then surely inspired by [wiki]Cherry M5[/wiki]. But magnetic reed is quite different from what Cherry was doing, of course.

The inevitable question: are the caps MX compatible? And vice versa?

I've seen metal stab inserts on IBM beamsprings. Perhaps ABS was harder to work with back in those days. And I've seen cases as full of empty air as that one. My Honeywell feels surprisingly light, too. But its nasty, flimsy case just wants unclipped so you can enjoy the Micro Switch PCB in all its glory. This keyboard is better matched.

LF linefeed and CR carriage return were often different on old boards. Again, the Honeywell:



Wikipedia explains the difference. It all boils down to printers! Real system output, before all these fancy glass terminals…

[terrycherry]

I am not much of a typist but could probably get my wife to type out a few lines for a vid. I don't plan on opening any switches for a while but when I do I will share more pictures for sure.

As for the switches they are linear with about 4.5mm travel. The number pad has stiffer springs than the rest of the keyboard and are a little bit to stiff for my liking but the others feel very nice in my opinion

That's good to see the video typing of rare keyboard.
I can see your keyboard have 4 different color housing: Begie, White, Orange, Black.
And the numeric pad actually have 3 different colors. I think the color could mean the travel it has. Which one you think is stiffer?

[rsbseb]

The color of the plastic is not relevant and appears to be recycled. Even the tan ones are a variety of shades. The switches with the black dots on them are stiffer, it does not show up very well but the black switches also have a black ink mark on them and are stiffer. The switch with the red dot has a strait stem instead of an angled one. The red switch has the soft spring in it.

[rsbseb]

Here's a short video of some absolutely meaningless typing.




http://vid183.photobucket.com/albums/x2 ... tboard.mp4

[kps]

Here is what?

HERE IS

[10ko]

The key caps are Cherry M9 compatible.
I hope to show you disassembled switch.

[10ko]

That is.

[Chyros]

I think that's the first time I've ever actually seen the magnetic reed in a magnetic reed switch. Very nice photo!

[stratokaster]

Good old 155-series ICs.

You can think of them as discrete logic gates. That's why it takes dozens of them to do what a typical Intel keyboard controller does.

[terrycherry]

rsbseb: Late to see your update. Thanks to share the video and switch! Thanks to 10ko for the assemble photo. Seems like you have the same keyboard.
I got the luck to find this keyboard(different layout) with the original computer!
[PC][Bulgaria][1984.03.29]IZOT(ИЗОТ) 1031C keyboard
CPU: Eastern Germany i8080 clone; RAM: 64 KB
seller site http://olx.bg/ad/pravets-82-izot-1031s- ... DYb0t.html



Here's the owner blog.(Ukrainian) He collected lots of old rare computer at home.
http://retro-pc.blogspot.hk/

Here's the pdf manual. It's for Bulgarian, like the wrestler Rusev.
http://www.retrotronics.info/modules/ne ... storyid=13

[terrycherry]

The color of the plastic is not relevant and appears to be recycled. Even the tan ones are a variety of shades. The switches with the black dots on them are stiffer, it does not show up very well but the black switches also have a black ink mark on them and are stiffer. The switch with the red dot has a strait stem instead of an angled one. The red switch has the soft spring in it.

As you said, I noticed the details as following.(color means the shell shape)Is that correct?(If you can show me the switches on full keyboard, it could be great.)
I can see the keyboard has the Caps Lock. Is it the latching lock switch?

-(Linear)Beige
various key

-(Linear)Black
(numeric area)7; 5; 6

-(Linear)Black with dot
(numeric area)8; 9

-(Linear)Orange
(numeric area)OFF LINE

-(Linear)White with dot
\; (numeric area)0; _; 1; 2; 3; 4; ,; -; ON LINE; (two blank keycap)

-(Linear)White(straight slider)
(numeric area)Enter

Switch performance: Harder > softer
(Linear)White with dot = (Linear)Black with dot > (Linear)Beige = (Linear)Black = (Linear)White(straight slider) > (Linear)Orange

[DMA]

Reminds me of a first fancy keyboard I had access to.

http://forum.maxiol.com/index.php?act=a ... st&id=8057
Capacitive! Linear feeling, completely silent.
Heavy as hell - 4 kg, pardon my metric units. Just look how thick the metal is.
5V, 900mA.
Driving voltage 100V, driving frequency 200kHz (Yes, I've found the technical manual. Scans, quality is abysmal.)

Every key contains it's own resistor and transistor
http://forum.maxiol.com/index.php?act=a ... st&id=7870
(visible on the photo with case removed)
http://forum.maxiol.com/index.php?act=a ... st&id=7947

bottom of the PCB:
http://forum.maxiol.com/index.php?act=a ... st&id=7951

It was a part of a soviet almost-VT52-compatible terminal.
http://forum.maxiol.com/lofiversion/ind ... t5118.html

[terrycherry]

Reminds me of a first fancy keyboard I had access to.

http://forum.maxiol.com/index.php?act=a ... st&id=8057
Capacitive! Linear feeling, completely silent.
Heavy as hell - 4 kg, pardon my metric units. Just look how thick the metal is.
5V, 900mA.
Driving voltage 100V, driving frequency 200kHz (Yes, I've found the technical manual. Scans, quality is abysmal.)

Every key contains it's own resistor and transistor
http://forum.maxiol.com/index.php?act=a ... st&id=7870
(visible on the photo with case removed)
http://forum.maxiol.com/index.php?act=a ... st&id=7947

bottom of the PCB:
http://forum.maxiol.com/index.php?act=a ... st&id=7951

It was a part of a soviet almost-VT52-compatible terminal.
http://forum.maxiol.com/lofiversion/ind ... t5118.html

Great! Never seen this keyboard.
I think you can open a topic to post more quality photos and talk more details about this keyboard.

[lot_lizard]

Nothing to do with anything relevant, but this color layout... Wow. The white alphas, light grey controls, subtle blacks and reds, all in spherical... It's delicious.

[Halvar]

We should do a group buy based on these colors!

[lot_lizard]

We should do a group buy based on these colors!

Haha... I'm always a day late and a dollar short it seems

[DMA]

Nothing to do with anything relevant, but this color layout... Wow. The white alphas, light grey controls, subtle blacks and reds, all in spherical... It's delicious.

Those colors actually scare me a bit.
Because the only time I saw them previously was a long time ago and it was this:

This is actually a PDP-11.