View Full Version : Review: Texas instruments ti99/4a

26th January 2012, 10:33
************ TI 99/4A *************

An introduction:

JUN 1979: Texas Instruments announces the TI-99/4 Home Computer at the Consumer Electronics Show in June at a retail price of $1150 with a 13" color monitor. It will not appear in any quantity until almost a year later however, and then it will prove to be a flop in the market place due to its high cost. Ti revise the computer and include a modulator to allow the use of the home TV.

Enter the lovely ti99/4a , 16 bit power house of home computing in 1981. This was the computer that other other manufactures were worried about, Texas instruments had full manufacturing facilities from the CPU to the plastic moulded cases. They had it all.All except a working processor!. The 8 bit CPU which was designed for the ti99 wasn't ready and had many bugs, so they hastily retro fitted the tms9000 16 bit CPU and created a Frankenstein 16 bit computer for the home market.It wasn't perfect and was crippled by the rushed design and pitiful cache (scratch ram)

Ti99/4a Spec

CPU: TI TMS9900, 3.0 MHz, 16-bit
Memory: 16KB VDP RAM (Video Display Processor RAM) (expandable to 192 KB with the use of YAMAHA V9938 - this was not a standard upgrade option but was a user-designed modification), 256 bytes CPU fast "scratchpad RAM"
Video: TI TMS9918A VDP (TMS9918 in the earlier 99/4, TMS9929/9929A in PAL versions. Distinct in being the only chip on the TI motherboard which had a heat sink on all models. Early models also had a heat sink on the clock generator, the TMS9904.)

Released: June 1981
Price: US$525 (without monitor)
How many: 2.8 Million
CPU: TI TMS9900, 3MHz
Memory: 16K RAM, 26K ROM
Display: Video via an RF modulator
32 characters by 24 lines text
192 X 256, 16 color graphics
Ports: ROM cartridge (on front)
Data storage cassette
Audio/Video output
Joystick input
CPU bus expansion

The Computer wars:

Commodore , atari and other were worried but soon after release the famous computer wars erupted between the big 3 and by 1983 the c64 was almost being given away, Atari were almost broke and the ti99 was being sold at a loss.Great for costumers but very bad for Texas Instruments. Commodore at this time were having hit after hit with the home computer,(PET, VIC, C64) Texas Instruments were not so lucky.

By mid 1984 Texas Instruments decided to quit the home computer market. Then, some 2.5+ million 4A computers were sold. It is to its credit that Texas Instruments during a long time maintained the service for owners of its home computers.

The End:
With the loses of $223 million during the first 9 months of 1983, on October 28th TI publically announces that it will bow out of the home computer business. It is a victim of its own self-destructive strategy to bolster sagging sales. In a series of price reductions and rebates over the last year, TI slashed the price of the computer in half, a move which cost the firm $50 on every computer shipped according to Business Week.
By the end of September 1983, the Ti Home Computer Division was more than $500 million in the red.

San Francisco based Triton Products Company is chosen as the fulfillment house for remaining 99/4A hardware and software.
Texas Instruments officially leaves the home computer market on March 28, 1984 when the last 99/4A is produced and the assembly lines are shut down forever.

Review: So the ti99 sucks?

Hell no!

The biggest problem was Ti , the controlled all the software & hardware making sales limited and new software expensive to produce and they paid the price for it. MBX mad a voice / joystick device that was late to the market and was sold only in the USA. The 99 is probably as close to the C64 as anything else on the market - home computer wise. Games like Rockford look so like boulder dash on the C64 you can't tell them apart. If anything only the sound really lets the Ti down but thats because the C64 was so good. The quality of the 99 shines through everywhere these things are almost military spec in design and are built to last. no dull plastic of mushy keyboards here, these are proper machines that look and feel like they cost big money. The keyboard is especially good and feels like a quality item, much as the very early IBM machines did. The graphics are always going to be poor to very good in gaming , think early C64, which after all is the 99s time line.

a good buy? you bet.

I got one for Christmas in 1983, it was probably the best Christmas ever ! And the Ti holds a very special place in my heart.[/COLOR]

Car wars

& some cassettes

Starship supanova
Escape the mugger
Nuclear disaster

One feature of the European (not uk) ti99 was that it shipped with the modulator and a scart fitting. No tv tuning here..

Ti produced a massive amount of hardware for the Ti including.

Cassette deck
Disk drive
32k ram
Speech module
Tv (monitor)

Languages , logo,pascal,ext basic

And lots more.

Atari even developed some games for the Ti, pacman, pole position, defender and others but the all time top games had to be.

Ti invaders ( best ever version?)
Hunt the wumpus

One of the biggest failures on the Ti - apart from 16k ram , huge price in the uk and no software ...
Was the bloody awful basic, now the basic isn't bad - c64 basic is bad! But the ti99 excellelled it's self by having double interruptered basic .. I.e twice as slow as it should be!

But by comparison , disk based assembler programs just flew at full speed and the clever way the ti99 handled graphics with minimal CPU load means it really flew. Cartridges (modules) showed this with great effect in games like parsec or defender , invaders is still the best and fastest commercial version of invaders.
The Ti also used its own Joystick pin out which is not Atari compatible - so your quick shot will not work with some hacking or an adaptor. Another problem was the 3/4 size keyboard that is cramped for typing but to be honest as a ten year old , i didn't notice. but what i did notice was that the Ti99 did not have lower case characters, only half size full case - strange but true.

Roll on twenty years and I now have most of the commercial software and lots of user written software for it and I have to say it is a similar machine to c64 in lots of ways. It's just a shame it needs 32k and a disk drive to achieve this...

AND the best bit of retro gear I've used i think the..CF7 or nano PEB as some call it.

CF7+ comes with a PIO port and connects to the 99/4a via cable. Easy to mount in a case.


*CPU RAM - 32K
*Emulation of three floppy drives
*Comes with 2gb Compact Flash (1gb available for storage)
*Parallel port - accepts standard "Centronics" cables
*Holds 1200 virtual 400kb diskettes (called "volumes") Original 99/4a diskette was only 90kb!)
*Built-in BASIC commands lets you format and mount volumes into the emulated disk drives.

I'll upload pics of the machine and some of the lesser know games / demos and a few vids too.

New hardware:

A new TMS9918 compatible graphics chip, based on an FPGA is also in active development and nearing completion. The chip, called the F18A is a drop in replacement for the original 9918 VDP, but features true VGA output, bypassic ageing analogue RGB systems entirely, and contains other enhanced features, such as (for example) removing the 4 sprites on a scan line restriction of the original 9918.

32k side expansion mini PEB released (CF7) as above.
32k ram
Printer port
Compact cf disk drive emulation.
9v power required.

Time line:

1981: June - The new and improved TI-99/4A Home Computer is unveiled for $525.
1982: January - TI introduces a Peripheral Expansion Box for the TI-99/4A for $250. Expansion cards are approximately $300 - $500 each.
1982: February- Unsatisfied at Texas Instruments, three engineers (Rod Canion, Jim Harris, Bill Murto) leave and form Compaq Computers, to build the world's first true IBM clone, the Compaq Portable. It was an incredible success.
1982: June - TI hires Bill Cosby as the ad campaign spokesman for their Home Computer. It costs TI $1 million a year.
1983: January - TI announces the TI-99/2.
1983: March - Texas Instruments introduces the Compact Computer 40 (CC-40). It runs on four AA batteries, lasting up to 200 hours.
1983: June - TI drops plans to market the TI-99/2.
1983: June - TI releases the plastic beige console version of the TI-99/4A.
1983: July - TI ships the 1 millionth TI-99/4A.
1984: January - TI has sold 2.5 million TI-99/4As.
1984: March - TI gives-up and drops-out of the home computer market altogether.

Demo / games / programs:

http://www.youtube.com/watch?v=bZzq-ebcM80&feature=youtube_gdata_player manic miner
http://www.youtube.com/watch?v=LN4fYDrQXkc&feature=youtube_gdata_player speech demo
http://www.youtube.com/watch?v=Bazbju-p_Tg&feature=youtube_gdata_player pitfall
http://www.youtube.com/watch?v=jqKSK6jyBTU&feature=youtube_gdata_player miner 2049
http://www.youtube.com/watch?v=R7kArHD0efA&feature=youtube_gdata_player 512K mega cartridge hack
http://www.youtube.com/watch?v=9CyfHZui0g8&feature=youtube_gdata_player Bill Cosby advert
http://www.youtube.com/watch?v=VLV0tcpxYjg&feature=related Pole position
http://www.youtube.com/watch?v=6GN497HptGE&feature=related Alpiner
http://www.youtube.com/watch?v=jLZrRtXtEbg&feature=related Star Wars
http://www.youtube.com/watch?v=2vxq6av3Tms&feature=related Buck Rogers
http://www.youtube.com/watch?v=RxiLbFSeht0&feature=related Burger time
http://www.youtube.com/watch?v=Vbdkm4_iMe8&feature=related Ti Invaders


Mod Player

---------- Post added at 09:33 ---------- Previous post was at 09:23 ----------

Please forgive my spelling or grammar errors , I wrote this on an iPhone. I'll go over it later at home and add some other bits.


26th January 2012, 11:26
Mike thanks, that's a great write up. :thumbsup:

I fired up my 4A the other day, still works!!! :D

Do you have a link to that FPGA graphics chip replacement at all? Would be interesting to read more on that.

If only somebody would develop a new VGA chip for Amigas :thumbsup2:

26th January 2012, 11:28

26th January 2012, 11:51
Nice work m8! :thumbsup:

26th January 2012, 11:52
Thanks - oh it's a quick write up nothing special. I'll add pics and stuff later.

Thanks for the link saviorx :-)

26th January 2012, 12:08

Thank you.

26th January 2012, 14:09

Thank you.

np, figured someone might find them handy, particularly RAM upgrading, which (given its overall power) is its only real fault.

it's actually a shame they didn't increase the ram in later models to 64 or even 128k

26th January 2012, 14:13
I've done the ram mod before and the speed mod in the past but really these are not needed when using the 32k PEB nano but of kit.

In fact the 32k internal mod may well cause problems with the PEB 32k.

The nano cf PEB is on EBay from time to time and is an excellent bit of modern kit , a must for any ti99 user. I used the original PEB back in the day and the nano is much better really.


26th January 2012, 14:21
somone in the US might even like to snag this for $33.57 BIN including a speech synth...


26th January 2012, 14:34
Our American friends can pick ti99s up from yard sales all the time , not so easy here in Europe.

26th January 2012, 14:46
well, regardless here are some brand new sealed disk drives for people who have PEBs, for a reasonable price.

but i am sure those are just falling off the swap meet tables as well.....


26th January 2012, 15:16
I wish I'd kept my boxed ti99 beige computer from
84 I think ...

Oh well


i read that wrong.. that link is for disk drives (new) ..great buy for someone :-)

i do wish i had kept my PEB with 80 track DD/DD disks (5.25 & 3.5)

26th January 2012, 19:45

the link you asked for

F18A – FPGA Based TMS9918A


26th January 2012, 19:49
Thankyou MJ :thumbsup:

27th January 2012, 09:22
No worries my friend :-)

It looks interesting , the same vdc is on the Msx and Aquarius I think..