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TI99/4a (corrected) Keyboard (membrane) Rebuild.
Posted: Mon Feb 05, 2018 4:06 pm
by vwbz80a
Afternoon reading Dan Moore's post I gave mine a closer look. Boo!
It WAS a membrane type.
And it was no longer working with my TS1000.
Tore it apart. The PCB seamed usable as did the key mechanisms.
Experimented with strips of aluminum foil, then went looking for some copper foil ...... none found.
Found small sheet of copper .005 thick. Cut to 1/4 inch x 5 ? Strips. Packing tape,clear, for holding to the PCB. The key mechanisms not strong enough to push metal strips into the PCB traces. So reworking the key mechanisms with a solid pin.
That's were I am now. Cutting .160 inch steal pins .700 inch long. 41 pieces.
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Mon Feb 05, 2018 4:09 pm
by gammaray
Wow. Do you have time to show pictures? Yes I am excited by every design project!
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Mon Feb 05, 2018 4:59 pm
by vwbz80a
gammaray wrote: ↑Mon Feb 05, 2018 4:09 pm
Wow. Do you have time to show pictures? Yes I am excited by every design project!
https://www.dropbox.com/s/3g92kcwqdqy3r ... 4.jpg?dl=0
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Tue Feb 06, 2018 2:44 am
by vwbz80a
This is my scan of keyboard pcb & top plastic membrane.
https://www.dropbox.com/s/kw7ebsb3m1fc5 ... 2.jpg?dl=0
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Sun Feb 11, 2018 6:20 pm
by gammaray
What are the copper strips for if you have the membrane and PCB?
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Sun Feb 11, 2018 9:52 pm
by gammaray
I think you have the later '/4A keyboard since they tried to save money on production.
The '/4 keyboard was Chiclet type.
- 1979_TI-99-4.jpg (115.03 KiB) Viewed 5668 times
Charles
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Thu Feb 15, 2018 1:01 pm
by vwbz80a
gammaray wrote: ↑Sun Feb 11, 2018 6:20 pm
What are the copper strips for if you have the membrane and PCB?
Copper strips are my attempt to replace the upper plastic /carbon tracks.
(Short answer)
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Thu Feb 15, 2018 1:04 pm
by vwbz80a
gammaray wrote: ↑Sun Feb 11, 2018 9:52 pm
I think you have the later '/4A keyboard since they tried to save money on production.
The '/4 keyboard was Chiclet type.
1979_TI-99-4.jpg
Charles
Correct. No Chiclet keys.
There is a Mitsumi # on the pictures.
The keyboard was a surplus item purchase back in '86-87. (cheap)
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Fri Feb 16, 2018 12:47 am
by gammaray
Re: TI99/4 (I think) Keyboard (membrane) Rebuild.
Posted: Sun Feb 18, 2018 9:50 pm
by vwbz80a
Just looked it over. Used the same diagram/table ..
Not recommending this approach. NOT!!!!
But I moved the cap tops over on the bottom row by 1 to the right .
[ shift ] ,z,x,c,v,b,n,m,
https://www.dropbox.com/s/kxfkwq15bx8ej ... 2.jpg?dl=0
Removed extra key mechanisms .(plastic plunger).
Traces now are correct. I'm thinking.
