Texas Instruments TI-99/4A

Funny isn't it, I placed a punt bid on one of these before I found the boxed version on a buy-it-now or best offer type auction, and then no-one bid on the other one, so I won that auction as well. So now I have two of them

This is a Texas Instruments TI99/4A Computer, that was released in the USA in 1981 and discontinued in 1984, it was an upgrade to the TI99/4 released two years earlier, the TI99/4(A) computers are significant for being the first 16 bit computers, all the way back in 1979. They also were among the first computers, along with the Atari 8 bit range, to use custom co-processors for graphics and sound. The machine has 16KB of video RAM and 256 bytes of scratchpad RAM for the CPU. It has 3 square wave voices and a noise channel for sound



The machine looks really good, it appears to have a metal top case, and there's a recess on the left side for a cartridge slot. There's a power switch with a red LED on the right hand side at the front, move to the right to switch on, and left to switch off



Here's the cartridge slot, it has a spring loaded flap keeping the dust out



On the right hand side of the machine is the expansion slot, which is covered by a sliding door, it slides up into the unit but is not spring loaded



This is the back of the machine, it has a joystick port, a power connector, and a video out, the sticker has been torn off on one of the machines



On the left side is another joystick port, you'll notice that none of the ports are labelled with any kind of description



Here's the underside of the machine



The PSU with proprietary connector



This is the TV encoder for the PAL region, it broadcasts on CH36



I can only assume this is a fancy cassette lead that plugs into a joystick port, but why it has two sets of plugs, I don't know

UPDATE: It is a dual cassette lead, it plugs into the rear joystick (that's not a joystick) port and allows you to connect two cassette recorders, both can save data from the machine (record), but only one can load data into the machine (play). If you only have one cassette recorder, you would use the lead with three plugs at the end, which are audio in, audio out, and the smaller plug is remote which the computer uses to stop the cassette motor running. The lead with two plugs are audio out and remote
The TI99 would differentiate between the cassette recorders by using the variables CS1 or CS2 after the SAVE command. Another weird thing with this computer is to load cassette programmes, you use the command "OLD CS1"
It would seem both cassette recorders get the same signal when saving, but the computer uses the remote line to control which one is in use



This is the box, it's plain on all the sides which are not shown



These are the game cartridges that came with the boxed machine, they are Indoor Soccer, Alpiner, and Video Games 1



Interestingly Alpiner has a different box to the other two, it has a plastic tray instead of a box with an internal cardboard sleeve for the cartridge, and it's a different size as well



This was in the box for Video Games 1, I'm not sure what it's for, it may be a keyboard overlay for the earlier TI99/4 model, it doesn't fit this model



The manuals



Leaflets



Time to fire this up and see if it works, and it does. You are presented with a boot screen which invites you to press any key to begin, then a menu screen, if you have a cartridge installed, there'll be more options here



It was at this point I discovered the keyboard is not great, it's nice to type on but there's no backspace key, which is really annoying, to delete characters you have to press FCTN and S to go back, then FCTN and 1 to delete, how annoying is that? Also you'll notice there's no lower-case characters, just smaller upper-case characters



The cartridge fits nicely into it's slot



This is Video Games 1, you can see the extra options on the menu screen are for different languages. Look at the date, 1979! There are three games available here



Here is Indoor Soccer, a bit tricky to play



This is Alpiner, you have to climb famous mountains while avoiding hazards, it's actually really good



This is the other TI99/4A, it works too, you may notice the badge with "Solid state software" written on it isn't on this machine



I noticed there's a plastic thing stuck above the keyboard on the non-boxed machine (on the right), and also, why no backspace key?

I don't know who thought that would be a good idea?


For more retro hardware check out my online museum here