ZX81 in a another case and 'proper' keyboard?

[sirmorris]

BBC micro keyboard unit.

http://goo.gl/GvY1qQ

Cheaper than 40 tactile switches from some suppliers..

[Ed in SoDak]

I just had to add these pics as my first post here. There's more than one way to chop up a TS-1000!

That's a TI99/4A keyboard pretty common to see for $5 back when I did this hack of a mod. The tinfoil keeps out the Aliens, no invasions yet!
-Ed

EDO_4458.JPG

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[sirmorris]

Classy! Welcome aboard

[Moggy]

Andy would love this!

[Ed in SoDak]

Thanks! I created this FrankenTimex about 30 years ago. IBM stands for "I Built Mine." It's about to get its third motherboard but at least the case and keyboard have survived!
-Ed

[Mike3]

In answer to your Question on modifying a Proper keryboard.. I just did a Ti-99/4a keyboard.. it didn't take but a couple of hrs.. The Keyboard is more comparable than I had first believed .. the 8-1/2 rows are already wired together and the 5 columns are also.. you need only to cut a few traces and then solder from the 8-1/2 rows to the ZX81 and from the 5 columns to the ZX81.. it works great.. I will try to post a more in detailed how to later with pictures if I can..

Mike

[Mike3]

Hello again.. It took awhile to get back. I finialy finished the mods/case..
I took a Ti-99/4 that didn't work that I bought at a flea market. for 5 usd... and converted the keyboard and case into a great looking ZX81..
I cut the case with a metal cutting bandsaw to the proper size and saved the end piece and grafted it back on with Epoxy and pieces of the leftover case,, on the inside.. then used Car bondo to hide the splice.. then painted it with Satin Black plastic paint..
Here are some pictures...On the keyboard I first traced all the Half row circuits and highlighted them with a sharpie.. and cut all traces connected to anythig not needed.. the I used an Ohm meter to check the columns and cut the traces not needed.. I think I only cut a total of 4 traces,, then it was easy to wire from the keyboard to the ZX81,,,

[Mike3]

More Pictures...If you can't tell by the pictures PM me and I can give you the connections from the keyboard to the ZX81 PCB..

Mike

[sirmorris]

WOW! That's a gorgeous machine! Well worth sacrificing a TI99 for

[Mike3]

Thank you sirmorris .. you will notice a bit of your hardware hiding behind the ZX81,, Thanks.... after an extended illness lasting over a year.. I have returned to my favorite little computer,,, I just burned a new eprom with version 6.6 and upgraded the firmware to 2.2 .. I didn't realize this had to be done in order to use the ZX-commander prg. but it works beautifully Now.. Now trying after 30+ years to get back into learning to program this little beast with Machine Language..

I decided to post the connections between the ZX81 PCB and the keyboard.. here it is..
Keyboard
0 9 8 7 6 1 Q A Sh 6 Y H B
BRN RED ORAN Yellow GRN Blk Wite Pur Grn Grey Blu Yellow Orn

ZX81 PCB Looking at the PCB with the heat sink pointing toward you left to right
Columns Half Rows
1 2 3 4 5 1 2 3 4 5 6 7 8
Grn Yell Orn Red Brn Blk Wlte Grey Pur Blu Grn Yellow Orange

I also cut the large space bar traced and wired it into the small space key.. t make a more natural feel

Mike