deskthority

Looks great! I agree with fohat, the ANSI enter/backslash and backspace mod is well worth doing for the 2u backspace and does not require any non reversible modifications.

fohat wrote: ↑Whoa!

That mat looks very thick and stiff.

Will it squish?

Nice pickup. Good luck with straightening that case. That should be an adventure!

This thread covers the various options people use
keyboards-f2/replacement-foam-mat-for-i ... t8033.html
and this one from GH
https://geekhack.org/index.php?topic=58814.0

It's simply the IBM designation for the technology used for the line of keyboards.

Smart idea. The slight loss in travel seems very acceptable to have a functioning key.

Noodle called it, its alps spring over membrane. I have a few loose examples of this switch as well. Also the same switch with white slider.

Nice work! Agree, that clicker is a bit much.

I had a friend who was able to debug code by listening to the PC beeper tonal fluctuations (this is actually a true story) I had a problem about 20 years ago where I had to use subtle variations in drive light activity as part of my debugging for a file replication problem. Of course this was back ...

@__red__ touched on two important factors that most beginners under appreciate: flux and tip selection. Flux does wonders for getting solder to behave nicely and the correct tip allows for quick work without over or under heating. This old video covers from Pace the basics better than any other I ha...

Edit: hansichen already mentioned this, but... The wiki is invaluable and I have a long list of things I have been meaning to add. My biggest hurdle is the amount of time it takes to add a set of pictures to the wiki. The current process requires adding each picture individually and entering the sam...

It is most certainly convertible. The problems have been that existing configurable converters such as Soarer's do not handle it correctly at all times, specifically the reset line. There are a number of "XT" keyboards that have proprietary variations from what IBM used with it's PC/XT keyboard and ...

Really nice find.Thanks for sharing and providing such a detailed writeup.

Definitely the slider over dome. Keycap profile is wrong for 725 series (i.e. space invaders). Space invaders has a lower profile and in 99% of cases a stepped caps lock key. I have never seen an RT-6xxx with space invaders. RT-8xxx indicates space invaders.

Really nice work! I love all the details.

All the silver ones are hermetically sealed, axial electrolytics, probably tantalum. The yellow ones are either polystyrene film or old avx molded ceramic; 12nF from code ('123')

Comparing it to others one the same page, it is definitely the capital letter 'O' and not the number zero '0' but the question is, is it a typo.
@snuci, do you happen to have the schematics for the 5110 (i.e. Ibm 5110 System Logic Manual)

The empty socket was most likely for a ROM chip. Currently the keyboard has an Intel 8048 microcontroller which has on-board ROM for program code, but PCB offers the flexibility of using an 8039 or 8040 microcontroller which does not have ROM and store the program in the separate ROM chip. In additi...

Oh, and You have to pay attention to point 2) of the guide " the selection of a device address then makes the data available on the bus in bits lines " So the 5110 keyboard should worlk like this: a) a key is pressed and released b) a "scan counter chip or circuit" records the keycode in an interna...

From the pinout you posted, I would assume, as lucar mentioned, that the data is parallel, i.e. Kbd 0 through Kbd 7 are the bits of the scan code and Kbd P is a parity bit, although a parity bit is unusual with parallel data.

What does the back label say? I have a very similar board (without the awesome caps) that sends ANSI key values via asynch serial.

Thanks for posting the video! I love the thockiness of these boards. Just finished sprucing up these two for engicoder. I thought they looked particularly nice. Thank you, snacks! I am really looking forward to these two. I will be able to reunite "The Patriot" with his as yet un-named 101 key Libe...

Great video. Very clear even if it is upside down

I think a lot of the noise you are hearing is related to the spring and space invaders definitely bind a bit when pressing from the corner rather than the center. My best results came from ultrasonic cleaning of both the slider and bottom housings, but as you said, this requires quite a bit of work....

This made my evening! Thanks, snacks!!

This is a truly amazing piece of history. It has the processing unit, display, storage and input in a single unit. I hope to see more coverage of this on your site!

To play the cynic, there is also the possibility that this is something clickclack created. He does have some skills with plastic.

So what do you guys think? Is it worth it to play around with the protocol a little bit or just do controller replacements on these as well? I might tinker with it a bit just for fun and to learn. I would try making a converter. A few more scan code captures should tell you if there is a pattern. M...

The Patriot. The color scheme and layout make it a winner.

//gainsborough wrote: ↑Woah, those pictures are old! That's pretty neat, though.

Our definitions of old differ I bought my first computer before those photos were taken.