Texas Instruments TI-99/4A video RAM fix

[@adamv242]

A lifelong Atari fan, I always had a fondness for the TI as well. Great keyboard, a very nice built-in BASIC.

[@flashjazzcat]

I really liked this machine too, which is why the various puzzling design decisions regarding the keyboard editor, etc, are so frustrating.

[@cbmeeks]

The TI-99/4a was my first computer. I have many of them now and still use them. It really is a strange computer that you either love like me, or hate. lol

[@jonathanwhiteside6092]

Of all the computers I own, I have to say that the TI 99/4a has the best video signal of them all in unmodified form. I use a CoolNovelties component cable via an OSSC to HDMI and the image quality is unmatched other than by machines like my 65XE and 800XL that have VBXE's fitted. Weird machine though.

[@cathrynm]

Suspect TI had decent analog engineers around at the time they designed this machine.

[@flashjazzcat]

Seems so, yes. I've been reminded of the RGB mod for this machine, which is apparently sublime, but not having even seen component first hand, I'm sure it's excellent given the quality of RF out of the box.

[@oldradiosnphonographs]

my 1983 beige one has this freaking issue! nice to see there is a solution

[@cbmeeks]

On the speech synthesizer, the door does nothing. It was meant to accept new speech ROMS but that never happened. And as for the joysticks...they are quite awful as you will soon discover. LOL

[@NotMarkKnopfler]

To delete a character, move the cursor back (fctn key and S key) on top of the character, then press fctn 1 (DEL). Easy when you know how 😅 still not as complex as the spectrum keyboard 😊

[@flashjazzcat]

LOL - thanks for that. Easy when you know how, as you say. :D

[@JoseArzacSolis]

My first computer was a TI-99/4A. I loved it. The packaging, manuals and documentation were excellent. And I did use a tape recorder to store programs, but I never got a voice synth.

[@flashjazzcat]

Yes: presentation was generally excellent. Just such a quirky machine with the benefit of hindsight.

[@tenminutetokyo2643]

Nice lighting!

[@flashjazzcat]

Thanks!

[@mikegage3326]

Nice work.

[@flashjazzcat]

Thanks!

[@PG-gs5vb]

You have to put a chatty dwarf inside the speech synth box to make it work.

[@flashjazzcat]

Ah - I did wonder. :)

[@ukcroupier]

The RF signal on mine is superb too, actually better than the component using coolnovelties cable (not a dig at coolnovelties, i think the machine is just built that way)

[@jasejj]

This was a capable and interesting machine, but unfortunately it was never going to work in the UK. We used tape for games in the early days, and typically never bothered to expand our machines. Out of the box, the TI was completely unsuited to games thanks to the machine's inability to run machine code from BASIC, which immediately prevented good quality cassette based games from being available. I thought at first that this might have been my friend's machine from back in the day - as there can't have been many of these in the North East (friend lived, still does, in Sunderland). His dad was a massive Sanyo fan so it surprised me even at the time that he ended up with one of these rather than an MSX!

[@flashjazzcat]

Stuff comes in from all over the country (and world, in fact), although I do get the odd local client coming down to the house in a car. This one was posted in last year from somewhere in the UK, but I suppose you never know where this machine's been during its long history.

[@Miler97487]

I had a TI-99/4A in the day and those joysticks are terrible. There were third-party outfits that made adapters that allowed Atari-compatible joysticks to be used on the TI. My father bought an adapter by WICO in 1984 because we went through three or four pairs of TI joysticks that kept breaking, not to mention the awful feel and the clumsy position of the fire button. Using a quality Atari-compatible joystick sure made a big difference.

[@flashjazzcat]

Interesting. It never for a moment occurred to me that such adapters had been produced.

[@MoparStephen]

I wonder if rufies can erase the TI's 16k of memory? Bill would know!

[@flashjazzcat]

Not according to the Pennsylvania Supreme Court, LOL

[@NotMarkKnopfler]

The door on the speech synth doesn't serve any function. The original intention was to produce different voice ROMs with male/female voices and different vocabularies etc. but it never came to fruition.

[@flashjazzcat]

Ah - thanks. So it's bascially just a handy storage compartment. :)

[@joopidema]

There is a fix for that Alpha Lock problem using a diode.

[@flashjazzcat]

Really? I assumed this was by design owing to signal contention with the joystick or something. Nice.

[@galier2]

3:41 the ram chip for bit6 (i.e. the 2nd lowest bit) is dead. Let's see in the video if I'm right.

[@flashjazzcat]

We'll have to assume you were right. I'm still pleased to have replaced the whole lot, in case another soldered-in chip went bad in the future.

[@NotMarkKnopfler]

The PAL TI-99/4A outputs YUV from its video connector. Maybe that's why the cable doesn't work?

[@flashjazzcat]

You mean that the component inputs on the TV might be particular about it being YPbPr instead?

[@alexcochrane1966]

Good computer, terrible joysticks. The speech synthesizer needs speech enabled carts or extended basic.

[@repetto74]

The speech synth module has all the required electronics in it to make it work. The flap door does not serve any specific function, probably an extra feature that was lately dropped :-). You can test the speech module with the game cart PARSEC.

[@flashjazzcat]

Thanks - that's most interesting and I'll be sure to test it out if I ever have another one of these machines in my hands.