Questions tagged [ti-99]

For questions about the Texas Instruments TI-99 series of micro-computers, in particular the TI-99/4A.

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4 votes
0 answers

Did Atari lobby against FCC regulation change?

In the 1970s, FCC limits on RF emissions applied to 'anything that plugs into a TV', and were stringent and difficult to pass. Atari went to extraordinary lengths regarding this when designing their ...
14 votes
2 answers

Why did Extended BASIC on the TI-99/4A only allow 28 of the 32 sprites?

The Video Display Processor (VDP) of the TI-99/4A was capable of displaying 32 hardware sprites. These sprites were unusable with the default, built-in BASIC that TI provided. However, an enhanced ...
2 votes
1 answer

TI-99/4a RF modulator, fuzzy video

I recently purchased a TI-99/4a. Well, 2 actually. Both work, but I only have one RF modulator. I ordered a composite adapter, but that hasn't arrived yet. Both work on the RF modulator, but the ...
5 votes
1 answer

Audio cassettes on TI-99

One of the features of the Atari machines was that the left audio channel on the cassette was connected through to the television speaker. This was used to produce things like "Conversational ...
10 votes
3 answers

TI-99 display interference

I had occasion to touch a TI-99 only once, circa 1985. The machine in question was part of a lineup of 8-bit machines that also included a late-model Atari and another, perhaps a Coco but I can't ...
9 votes
2 answers

Is it possible to use a TI-99/4A cassette cable with Digital Audio devices?

I would like to save and load BASIC programs with my TI-99/4A. The TI-99/4A can be connected to a cassette recorder for this purpose. Buying a cassette recorder and cassette tapes seems unnecessary ...
2 votes
0 answers

How many units did TI Invaders sell?

I'm trying to get a feel for the scale and dynamics of the early home computer game industry. Statistics for arcade games and console cartridges are relatively easy to come by, e.g. that Pac-Man on ...
6 votes
1 answer

What was the purpose of GROM (vs ROM) in the TI-99/4a?

The TI-99/4a had a cartridge slot on the front of the computer which accepted "solid state cartridges" (as TI called them). These cartridges would typically contain ROM (Read Only Memory) like many ...
19 votes
4 answers

Why did the TI-99/4 have two databuses?

Wikipedia says on Russian page: Однако к 16-разрядной шине были подключены только 256 байт статической памяти и системное ПЗУ. Остальная память (ОЗУ) и периферийные устройства были 8-разрядными и ...
11 votes
2 answers

How to fix a TI99/4a membrane keyboard?

I recently purchased a 1982 TI99/4a that has a defective keyboard. The keyboard is a Mitsumi with normal keys, but membrane type contacts. When I press the contacts (gently) with a plastic stylus ...