Unresponsive Keys

[C_Dingo]

Hi, new to the forums here. Not too long ago I came into possession of a TI-99/4A along with some random cartridges. The system is in good condition, and I tried it out shortly after getting it (had to get a video cable as that was missing) and all seemed well. Recently I've decided to focus on getting a few games for it, but I ran into a problem with the keyboard. The letters QWERT aren't working at all. I'm not sure what happened, as I remember the last time I played a game they were working fine; the system has been in the box since then. I've tried taking it apart to see if there was dirt or anything that could be causing a problem, but didn't see anything that may be causing this. Is there anyway to fix this, or will I be better off replacing the entire keyboard? I tried searching to see if there was already a solution out there, and found that there were different models of the keyboard produced by different companies. It also seems that the quality of they keyboard varied between manufacturer. How would I tell which model my TI has in it?

[Omega-TI]

You might find some good information in the following threads:

 

http://atariage.com/forums/topic/228582-restoring-the-keyboard/

 

http://atariage.com/forums/topic/160958-help-fixing-ti-994a-keyboards/

[C_Dingo]

Thanks for the links. I had come across the first one when searching previously. I guess it looks as though the easiest solution is to just replace the entire keyboard.

[+Ksarul]

On keyboards--pop one of the keys off. Do you have a square box with a pair of gold contacts in a cavity below the key cap (this part would remain with the keyboard). If so, you have one of the better keyboards. Often a cotton swab and some alcohol will resolve the problem (work gently so as not to bend the gold contacts). If the part under the key cap is a plus-shaped post, you have one of the membrane keyboards. These are prone to failures like your current problem (although sometimes similar problems show up on the first type of keyboard I mentioned too--they are just much more common on the membrane types). If it is a membrane type, your best bet is full keyboard replacement. . .

[C_Dingo]

It looks as though I have one of the membrane keyboards. I'll look into replacing it with one that has the gold contacts. I appreciate all the help. Hopefully I can get this resolved soon and start enjoying some of the games for the system.

[UKRetrogamer]

Freakin' unresponsive keys...

 

Earlier today, I replaced the CMOS battery in an Acorn BBC Master Turbo (unused in over 2 years), only to find NEITHER the left OR the right Shift keys worked. All other keys were OK so I assumed there was a single and more fundamental problem with the hardware and opened a thread on the StarDot forums. (Bad CMOS, broken trace, yada-yada...)

 

It turned out BOTH keys needed a thorough dousing with switch-cleaner and repeated hammering.

 

Coincidence, huh? If any other key had exhibited the same problem, I wouldn't have given it a second thought and just reached for the spray but BOTH (and ONLY) Shift keys? Pah!

 

Sorry this doesn't help the OP in any way but it does help me by getting this off my chest!

[+Schmitzi]

Hi,

 

can you please check your "CNTRL"-key ? Please have a look if it is working.

 

If so, I would guess the keyboard/connector-wire to PIN 10 is interrupted.

 

schmitzi

[C_Dingo]

I checked the wires, and it looks like the soldering on one is loose. This may be what is causing the problem. I'll try fixing that first and see if it works afterwards. Thanks for the suggestion on that.

[+Schmitzi]

yep.