Pravetz KBD-8A

[BlueBär]

1.jpg (226.21 KiB) Viewed 3592 times

So I recently got this keyboard from Ebay after somebody posted it here. The keyboard stems from a Pravetz 8A computer, which is from what I understand the Bulgarian counterpart of the Apple IIe. The 8A was build between '86 and '88. If you want more information about it here's what I have found: http://www.pravetz.info/pravetz-8a.html

When it arrived it was extremly dirty and the keycaps were in a disgusting condition. For those who never bought an old keyboard, the first step is usually to put the keycaps in some warm water with dental tablets. They didn't really help this time and I had scrub each keycap - in hindisght that was a good decision since the legends are engraved. The keycaps are not doubleshot and probably ABS. They have a slightly spherical profile and feel very solid.

2.jpg (241.96 KiB) Viewed 3592 times

The keyboard features some cross-stem switches (not MX compatible), most of them with black housings, but with some brown and beige housings as well. The switch on the spacebar has a grey stem and feels heavier, but I couldn't feel a difference between the different housing colors, I don't think they make a difference. I don't know what exactly that is on top of the grey stem but it didn't come off. The enter key is the only key that uses two switches.

5.jpg (289.21 KiB) Viewed 3592 times

Now to the switches. As you can see the switches are secured with some screws on the PCB. I don't think there's an option to plate mount these switches.

10.jpg (328.56 KiB) Viewed 3592 times

From the outside you can already see the most important part of the switch, the reed switch. Opening a switch is not as easy as you would think, there's a part of the housing molten so that it doesn't open without scraping a bit of the molten part away. Hard to explain, but worse than glue. There's also an additional tiny copper pin that goes through a tiny hole to prevent opening it as well. If you noticed, one of the legs to fix the switch on the PCB broke off

12.jpg (260.25 KiB) Viewed 3592 times

13.jpg (233.41 KiB) Viewed 3592 times

The switch inside is quite simple, a magnet is attached to the slider and goes next to the reed switch when the key is pressed. A reed switch works with two very small metal plates that connect when a magnet is brought nearby. The slider itself only hits the bottom of the housing, it's not really clear on the photos.

15.jpg (397.31 KiB) Viewed 3592 times

16.jpg (287.26 KiB) Viewed 3592 times

18.jpg (233.04 KiB) Viewed 3592 times

19.jpg (296.08 KiB) Viewed 3592 times

And that's it! Here, have a typing video:

There's a few more photos in my thread on Geekhack and I can take some more if needed

[HaaTa]

Yay, now I don't have to worry as much taking pics of this one

Yours also looks in better condition

[kint]

Very atmospheric video. I like the sparkling keycaps and the mellow movement of the shaddows on the left. Did you type on it while lying on the floor? Nice keyboard too.

[Muirium]

For engraved caps, they look pretty damn good. Better than those crazy bandy-legged LEDs! Sounds quite nice too in the video. The space bar stabiliser is refreshingly quiet compared to many 80s boards. Could still use a little lube, though.

[nourathar]

great pictures and video, and that board looks good too ! would love to try reed switches one day..

[mr_a500]

Yes, I like the lighting in that video. I wonder if those keycaps were originally white and the plastic yellowed or if "butter yellow" was the intended colour (doesn't look as bad as most yellowing). I didn't think they still did engraved keycaps in the late 80's. Eastern European countries were obviously slower to modernize. (which is certainly good for keyboards)

[BlueBär]

Yay, now I don't have to worry as much taking pics of this one

Very atmospheric video. I like the sparkling keycaps and the mellow movement of the shaddows on the left. Did you type on it while lying on the floor? Nice keyboard too.

The sparkling was actually not intended and I just noticed it when I cut the video
The keyboard lies on the floor with me kneeling in front of it.

For engraved caps, they look pretty damn good. Better than those crazy bandy-legged LEDs! Sounds quite nice too in the video. The space bar stabiliser is refreshingly quiet compared to many 80s boards. Could still use a little lube, though.

The caps have a long long cleaning session behind them, they were disgustingly dirty (this picture is still harmless, especially in comparison to what amount of dirt was on the switches) when they arrived.
The stabilizer definately needs lube, but I'll do that when I decide the fate of the board
I kind of want to replace the springs with new ones but don't know where I could find some that will fit.

Yes, I like the lighting in that video. I wonder if those keycaps were originally white and the plastic yellowed or if "butter yellow" was the intended colour (doesn't look as bad as most yellowing). I didn't think they still did engraved keycaps in the late 80's. Eastern European countries were obviously slower to modernize. (which is certainly good for keyboards)

I think they were always a bit cream colored but not as much as they are now. I don't mind, the current color is quite pleasant and the yellowing is even.

[dorkvader]

Hmm, the keycaps look like they might have been doubleshot as blanks and the legends then engraved. It's not too uncommon to see, especially for boards with really funky legends. Care to check?

Anyway: thanks very much for posting this keyboard and such good pictures! I rather like reed switches, and these look to be rather nice. Good find!

[BlueBär]

Hmm, the keycaps look like they might have been doubleshot as blanks and the legends then engraved. It's not too uncommon to see, especially for boards with really funky legends. Care to check?

Nope, caps aren't doubleshot. Also quick thickness comparison with Triumph-Adler caps (should be the same as thick Cherry/GMK/BSP). Sorry just Nexus 4 quality but I think it will do

IMG_20140129_013908.jpg (573.86 KiB) Viewed 3516 times

Anyway: thanks very much for posting this keyboard and such good pictures! I rather like reed switches, and these look to be rather nice. Good find!

Thanks!

[woody]

Yup, reed switches were the norm for most of the Pravetz-8 series: 82, 8M, but not 8C. Not sure about 8A, 8E, because they're too rare. Not sure about 8D, at least later versions weren't reed switches.

They have this very pleasant faint "click" upon closing the contact. I had to replace a reed switch or two because of chatter, which could've just been a faulty/marginal debouncing in the keyboard controller, too.

[phosphorglow]

What a fantastic looking board - I love the engraved caps. Super neat switch mechanism. (Neat looking machine too - the texture on the case looks cool).