blakespot Posted December 9, 2017 Share Posted December 9, 2017 I have a '99 that I fitted with a F18a some months back. I've used it a good many hours without issue, and some of that was online through TIMXT with a WiFi232 -- so the keyboard has been working fine. I'd not used the TI in a few weeks and turned it on and noticed in the FlashROM '99 menu that certain keys were not working. Those keys are: HJKL; and SPACE Press normal, hard, etc. and they don't register -- TI BASIC, TIMXT, Forth, etc. But, I left the machine on for a while and I notice they keys now do work...but you need to press them just a little harder than "normal" for them to trigger, and when you do, they usually repeat a few times. One depress of 'K' results in 'KKKK' and such. So something is really strange here. I assume the hardware heating up is the change, but the repeat action baffles me. Can anyone make anything out of this? I see no other oddities with the system. I disconnected my PEB and that had no effect on the situation. Is this a specific IC failing? Or...? Thanks. bp Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted December 10, 2017 Share Posted December 10, 2017 First, do you know what kind of keyboard you have? Is it one of the Mitsumi or Alps types (as both of those can be very problematic)? If it one of the many other types (the ones with the square boxes under the keytops with metal fingers in them), I would try to carefully clean the fingers and verify that they still touch when the key is selected. Another possibility is that one of the keyboard lines is losing connectivity somewhere. . . Quote Link to comment Share on other sites More sharing options...
+Lee Stewart Posted December 10, 2017 Share Posted December 10, 2017 HJKL; and SPACE Those keys are all on pin 4 of the keyboard connector, so I'm with @Ksarul’s last suggestion. The repeats can be sticking keys or multiple making/breaking contact with the flaky connection going to pin 4. ...lee Quote Link to comment Share on other sites More sharing options...
TheTIGuy Posted December 10, 2017 Share Posted December 10, 2017 Don't worry, replacements shouldn't set you back more than $25 after Christmas time . Quote Link to comment Share on other sites More sharing options...
blakespot Posted December 10, 2017 Author Share Posted December 10, 2017 I guess I may as well open it and reseat the kbd cable, etc. even though Ive not yet identified what ICs if any could alternatively be the problem. Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted December 10, 2017 Share Posted December 10, 2017 If reseating the cable doesn't solve the issue, you could reseat the 9901, as the keyboard connector ties back to that chip. Carefully check the ribbon connector at the keyboard side for a weak solder joint or break, especially if you removed it earlier to install the f18a. Quote Link to comment Share on other sites More sharing options...
blakespot Posted December 10, 2017 Author Share Posted December 10, 2017 Yea... I pulled out the keyboard and took a look at the cable's solder connection to the keyboard's circuit board. Look close. Full-sized original can be seen here. Doesn't look so good, and the cable bends out from the plastic keyboard backplate so easily. Prob desolder that cable and either clip back that cable and expose some "fresh" wire or try and run individual wires from the board to the edge connector, having removed the original ribbon cable entirely. Or, other approaches? Thanks. bp Quote Link to comment Share on other sites More sharing options...
+Lee Stewart Posted December 11, 2017 Share Posted December 11, 2017 Yea... I pulled out the keyboard and took a look at the cable's solder connection to the keyboard's circuit board. Look close. <snip> Full-sized original can be seen here. Doesn't look so good, and the cable bends out from the plastic keyboard backplate so easily. Prob desolder that cable and either clip back that cable and expose some "fresh" wire or try and run individual wires from the board to the edge connector, having removed the original ribbon cable entirely. Or, other approaches? Thanks. bp Well—the break on pin 4 confirms the problems with HKJL; and space. Several other pins are obviously compromised. You're on the right track, for sure! ...lee Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted December 11, 2017 Share Posted December 11, 2017 You definitely need to get better connectivity on a lot of those pins. . .especially number four from the right. Quote Link to comment Share on other sites More sharing options...
unhuman Posted December 11, 2017 Share Posted December 11, 2017 I always try goofy things. You could try to perfectly drop a blob of solder just to "fix" the broken wire. Quote Link to comment Share on other sites More sharing options...
Stuart Posted December 11, 2017 Share Posted December 11, 2017 If you've got a piece of IDE cable kicking around, you can replace the original cable with that - just use every other conductor and the spacing is then about right, and cut the unused ones short. 1 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted December 11, 2017 Share Posted December 11, 2017 It's a definite weak point in the TI design. The same thing happened to me when I installed my PS/2 keyboard adapter and again when I installed an F18A on a secondary unit. After 37 years things are not always a flexible. In most cases I follow the, "If it's not broken, don't fix it" approach, but dang it... upgrades are so much fun. Good luck! 2 Quote Link to comment Share on other sites More sharing options...
blakespot Posted December 12, 2017 Author Share Posted December 12, 2017 Fixed. Thanks for the help. https://instagram.com/p/Bckm4N_BKfR/ https://instagram.com/p/BclfmfMhZJo/ 1 Quote Link to comment Share on other sites More sharing options...
AMenard Posted December 12, 2017 Share Posted December 12, 2017 Is there space enough to install a pin connector instead of soldering the cable directly to the board? That way the cable could be made replaceable? Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted January 24, 2018 Share Posted January 24, 2018 In revisiting this thread, I firmly believe that if 'someone out there' was able to conjure up a new keyboard connector assembly for us, many would be sold. Oh how nice would it be to have a new flexible cable with a working connector! I'm sure many of us would buy one, two, three or maybe more. Heck, I'll commit to two right now! I think most people could solder on a new one. It's dealing with old fragile stuff that is so problematic. Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted January 24, 2018 Share Posted January 24, 2018 In revisiting this thread, I firmly believe that if 'someone out there' was able to conjure up a new keyboard connector assembly for us, many would be sold. Oh how nice would it be to have a new flexible cable with a working connector! I'm sure many of us would buy one, two, three or maybe more. Heck, I'll commit to two right now! I think most people could solder on a new one. It's dealing with old fragile stuff that is so problematic. I can make that happen I will look into it Greg 2 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted January 24, 2018 Share Posted January 24, 2018 I can make that happen I will look into it Greg SA-Weet! I'll take two! Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted February 6, 2018 Share Posted February 6, 2018 I can make that happen I will look into it BUMP Still looking to buy two! Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted February 6, 2018 Share Posted February 6, 2018 Connectors are the hold up Sent from my LG-H830 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted February 6, 2018 Share Posted February 6, 2018 Connectors are the hold up Sent from my LG-H830 using Tapatalk Okay, I'll check back later. Thanks Greg. 1 Quote Link to comment Share on other sites More sharing options...
jjh76 Posted February 7, 2018 Share Posted February 7, 2018 When looking for something else I spotted this ribbon cable at Micro Center and picked it up on impulse: http://www.microcenter.com/product/443175/200_mm_40_Pin_Plug_Leads_to_Plug_Leads_Ribbon_Cable The square connectors it has are just the right size to fit on the pin connector on the TI's mainboard, just tear off a section with he 15 wires you need for the keyboard. Then I soldered a right angle inline pin header to the keyboard. 2 Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted February 7, 2018 Share Posted February 7, 2018 a great idea, in fact I could put together a kit for this i'm sure. I'll do some looking for cheaper cables.. Greg 2 Quote Link to comment Share on other sites More sharing options...
Sinphaltimus Posted February 7, 2018 Share Posted February 7, 2018 (edited) a great idea, in fact I could put together a kit for this i'm sure. I'll do some looking for cheaper cables.. Greg I get mine via AMAZON... https://www.amazon.com/SINCODA-120pcs-Multicolored-Female-Breadboard/dp/B00ZWEFWO8/ref=sr_1_18_sspa?ie=UTF8&qid=1518022309&sr=8-18-spons&keywords=male+to+male+assorted+jumper+cables&psc=1 Edited February 7, 2018 by Sinphaltimus 1 Quote Link to comment Share on other sites More sharing options...
jjh76 Posted February 7, 2018 Share Posted February 7, 2018 one thing to note - the connectors on these ribbon cables are a little bigger than the original ones. With the alps keyboard shown in my pics it fits in the case with the keyboard side sitting right on top of the mainboard side with maybe a 1/8-1/4 inch between them. If you have one of the keyboards without the metal bracket and the pcb that gets screwed right onto the posts you might need to use a flat pin header instead of the angled one I used here 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.