Was there more than 1 variation of the TI-99/4?

majestyx · December 30, 2018

I could swear I had read a discussion here some time ago about there being two versions of the first TI Home Computer, the TI-99/4 but can't seem to find it anywhere. I am asking because I've recently gotten a hold of one of these, but am waiting on a cable to arrive in order to hook it up to a modern display in order to find out if it even still works. I'm just curious to know what was different between the two if indeed there were two versions of it. Unfortunately the one in my possession had the serial number scratched off of it so it may be impossible to determine which one I have. I think it would be based on the serial number matching up to the production run. Regardless, if someone could confirm or deny that there were two different 4's, I'd greatly appreciate it.

blackbox · December 30, 2018

I have used two different TI99/4 consoles. First up was an NTSC console which had to be plugged into an American NTSC monitor. This used a fairly standard analogue RBG output (later fed to a tv modulator). The US version had sound on the tv set.

Then came the PAL model, which used a different graphics chip and a very different- nearly unique- video output. The UK model ran slightly slower than the US model (50 fps instead of 60fps) which caused problems for Extended Basic programs where game play was thrown by a differing sprite speed. UK owners had to use the tv modulator to watch on a 625 line German tv set in colour (bizarre- TI produced the tv modulators for the European PAL standard, which differed from the UK PAL enough to make tuning properly with a UK TV a headache!). You could watch in monochrome on a monitor, but finding a colour monitor that could handle the very unusual signal was nearly impossibe (only the Tatung monitor could take the signal). The PAL 99/4 had a small speaker behind the console grill and a slider volume control at the front of the module depression (the US model had a nameplate here).

Edited December 30, 2018 by blackbox

+Ksarul · December 30, 2018

I have two of the 99/4 consoles with the sliders. I can only say one very important thing about them: do not ever use a regular power supply with them, as doing so WILL destroy the machine. All of the AC to DC conversion for this type was done in the external power supply, as the board for the sound slider occupies the space where the internal AC to DC power supply would normally have been. Both of mine are also NTSC machines. They were all produced during a very short period at the end of 1979 and the beginning of 1980 (I personally haven't seen any with production dates much beyond the end of January, but that doesn't mean there aren't any). The slider also shows the original purpose for the slot that has the Solid State Software badge in it. One other note: the correct power supplies for these are harder to find than the consoles are--and the power supplies are usually in dire need of recapping when you do find one. . .

majestyx · December 31, 2018

Thanks for the information! I should have mentioned this is a U.S. machine.

I knew there was some difference and it is the volume slider. Mine has the"Solid State Software" badge on it so it's definitely not the short run version. Not sure if it's the original power supply. It's a model AC95000 with the plug on a large cube transformer. It's been so long since I used a TI. I gave away both of my 4As along with a loaded PEB, speech synthesizer, joysticks, tape drive, plus tons of add-ons, software and documentation/magazines back in 2010 and wish I had them back!