Search found 383 matches

by gammaray
Wed Feb 21, 2018 2:13 am
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

D3 AND D4 should be crossed for Speccy operation so DPDT switch should work.
by gammaray
Tue Feb 20, 2018 11:30 pm
Forum: Welcome Area
Topic: Welcome to the SINCLAIR ZX WORLD forums
Replies: 5
Views: 78

Re: Welcome to the SINCLAIR ZX WORLD forums

Here! Here! ... With an capitalized DITTO! (What he said.)
by gammaray
Tue Feb 20, 2018 7:35 pm
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

Danmoore used 12" ribbon! He is pushing the envelope. Not really, I would expect 6' to be a problem. I could test it...
by gammaray
Tue Feb 20, 2018 6:58 pm
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

TIKEY WIRE CROSSOVER_2018-02-20_11-55-55.png
is this correct?
by gammaray
Tue Feb 20, 2018 5:48 pm
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

Do we need a driver board to repeat(amplify) the signals?
https://sinclairzxworld.com/viewtopic. ... oard#p2046
by gammaray
Tue Feb 20, 2018 4:22 am
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

Check to see if you have 2Y1 shorted with 2Y2 at "<". Following the traces it looks like it. I cant see diagram well enough to be sure. Let me know. UPDATE: I see the "2y2" trace cut in photo from a different angle. Still looking. One thing one have to decide first I guess is do you want all the key...
by gammaray
Tue Feb 20, 2018 2:41 am
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

P5 AND 2Y0 ARE NOT USED

This is what I came up with. Did you? Combined with the other table is fully decoded.
TI PINOUT.jpg
(2.62 MiB) Downloaded 32 times
I have not found any logic errors on your board yet but still not done...
by gammaray
Tue Feb 20, 2018 12:47 am
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

Did you see mooredan's PCB mod? There are however 4 or more different manufacturers. All seem to have a slightly different traces.

Which manufacturer is yours? Not entirely necessary except some sites have good pictures.
by gammaray
Mon Feb 19, 2018 10:06 pm
Forum: Hardware
Topic: TI99/4A KEYBOARD ADAPTATION
Replies: 26
Views: 959

Re: TI99/4A KEYBOARD ADAPTATION

What I failed to mention is that the traces for a particular key may have to be cut so that only the new wiring is used. Now if you are having trouble then maybe your skill level is not adequate and you need further help. (I know I do!) Please remind me which keyboard Manufacturer you have. I will t...
by gammaray
Sun Feb 18, 2018 10:07 pm
Forum: Hardware
Topic: TI99/4a (corrected) Keyboard (membrane) Rebuild.
Replies: 10
Views: 338

Re: TI99/4a (corrected) Keyboard (membrane) Rebuild.

Nice! Additionally, I am intending to reassign other keys like CNTRL, FUNCT, ALPHA and others but will need some circuitry to signal SHFT "X" for individual keys or map 8x6 matrix into 8x5.