MACHINE REFERENCE

Mattel Aquarius

The Mattel Aquarius was a Z80 home computer built for Mattel by Radofin in Hong Kong and sold from June 1983 at US$160, with 4 KB of RAM, a rubber keyboard and a cartridge slot. Mattel pulled out about four months later.

Why it matters

Radofin built the Aquarius from sensible parts: a Z80A, a Microsoft BASIC subset, a colour encoder and a cartridge port with direct, unbuffered access to the address and data bus. That open port is what hobbyists use today for RAM and SD card cartridges. The weaknesses were in what a buyer got for the money. Only about 1.7 KB of the 4 KB of RAM was free for programs, the rubber keys were hard to press, and the extra memory and sound sat in add-on boxes that pushed the real cost well past the Spectrum. Mattel launched it into a UK price war and left within months, and the board’s designers were not the ones who made that call. Sales are uncertain, with 8,000 to 20,000 units suggested, and the Aquarius II that followed sold in small numbers.

What to check before you buy

Ask whether the machine boots to the Aquarius screen and beeps when you press RETURN. A garbled screen with no response points to the CPU, ROM or RAM, and owners have fixed such machines with a new Z80.
Check that the keyboard works. The rubber keys were stiff when new, so a machine where some keys do nothing is a worse sign than one where they simply need pressing hard.
Test the cassette port with a lead you know works. Wikipedia says its pinout does not match TRS-80 cables, though a 1983 review says a Tandy lead worked, and the port has a reputation for failing to load.
Ask what comes with it. The Mini Expander, hand controllers, Data Recorder and RAM cartridges were all sold separately, and the basic machine has only about 1.7 KB of free memory.
Look at the picture on a CRT television if you can. One owner reports a monochrome picture on a Samsung LCD and glitching on another LCD, but a clean colour picture on an old CRT.

Mattel Aquarius home computer with blue rubber keys and a beige case on a white background

Photo: Evan-Amos, Wikimedia Commons (public domain)

Released

1983

RAM

4 KB, shared between video and the user. Reviewers found about 1.7 KB (1,731 bytes in one review) free for programs. Upgrades: a 4 KB pack and a 16 KB cartridge via the Mini Expander, giving 18,115 bytes free in one review. The maximum is given as 20 KB (oldcomputers.net), 36 KB (Wikipedia) and 52 KB (a Mattel claim quoted by Your Computer). Wikipedia notes a 32 KB cartridge gives about 34 KB total

CPU

Zilog Z80A at 3.5 MHz, made under licence by NEC (The Register). Computers Museum says units were produced with NEC, Hitachi and Zilog CPUs

Launch price

US$160 (Wikipedia, oldcomputers.net, Computers Museum). Sources disagree on how that compared with rivals: The Register says it was higher than the VIC-20 or TI-99/4A, Wikipedia says lower. UK prices: about £90 in the July 1983 Your Computer review (Gondolin, Wikipedia), £89.95 at launch according to The Register, which says it was cut from an earlier planned figure. The Mini Expander cost about £30 to £50 depending on the source. After Mattel left in October 1983 the price was cut to £59.95 (The Register), and a £50 machine was still listed in October 1984

Manufacturer

Designed and built by Radofin Electronics, Hong Kong (also the maker of Mattel’s Intellivision consoles), and sold by Mattel Electronics, USA. After Mattel left the computer market in October 1983 the rights went back to Radofin, and other companies including CEZAR Industries, CRIMAC, New Era Incentives and Bentley Industries also marketed the machine and its accessories

Form factor

Low wedge-shaped keyboard computer in a long beige plastic case with a black keyboard area and 48 blue rubber chiclet keys (Wikipedia; Gondolin counts 49). Computers Museum gives 340 x 150 x 45 mm and about 1.3 kg, which is the only size and weight figure found. The cartridge slot is on the right of the case and the power switch and indicator are on the machine itself

CPU

Zilog Z80A at 3.5 MHz, made under licence by NEC (The Register). Computers Museum says units were produced with NEC, Hitachi and Zilog CPUs

Chipset

Z80A CPU, two custom ULAs and a character ROM, two 2 KB RAM chips (AtariAge forum), and a TEA1002 colour encoder (Wikipedia). The Mini Expander adds a General Instrument AY-3-8914 sound chip (Wikipedia’s footnote and Computing History; Wikipedia’s text says AY-3-8910, so sources disagree). A PLA between the Z80 and the data bus XORs data with a lock code on the cartridge side, an early form of copy protection (Hackaday)

RAM

ROM

8 KB system ROM holding a subset of Microsoft BASIC, plus a separate character ROM (Computers Museum counts 10 KB in total). The system ROM is pin-compatible with common 2716, 2732 and 2564 EPROMs, according to an AtariAge forum answer

Graphics

One text mode of 40 x 24 characters with an 8 x 8 character cell (equivalent to 320 x 192 pixels), 16 colours. No bitmap or all-points-addressable mode: BASIC offers PSET, PRESET and POINT on an 80 x 72 semigraphics grid, and colour needs POKEs. A character set of 256 predefined characters with no redefinable graphics (Computing History). Outputs through an RF modulator to a TV, with no composite or monitor output

Audio

One channel under CPU control (Computers Museum calls it a beeper). The Mini Expander adds more voices: Wikipedia says up to four voices in total, The Register says three additional channels, and Computers Museum says two

Storage

Cassette via the Aquarius Data Recorder, and ROM cartridges. Computing History also lists a Quick Disk drive, a 300 baud cartridge modem, a 40-column thermal printer and a four-colour plotter. The Register says floppy drives and a modem were announced for 1984 but never appeared, so sources disagree about what shipped

Ports

RF (TV) output; cassette port on a 5-pin DIN; printer port on a 3.5 mm stereo jack (unidirectional serial, fixed at 1200 baud 8N2); cartridge and expansion slot on the right of the case with unbuffered access to the address and data bus. The Mini Expander adds two hand controllers and a second cartridge slot. Wikipedia says the cassette pinout is incompatible with TRS-80 cables, but the 1983 Your Computer review says a Tandy TRS-80 lead worked

A subset of Microsoft BASIC in ROM, called Microsoft Color BASIC by The Register and Aquarius BASIC 1.0 by oldcomputers.net. Keywords are entered with single key presses, and a clip-on overlay helped. Only a single-character delete: existing lines could not be edited in place (The Register)

PSU

Power supply is built into the case and not removable (Wikipedia, The Register). Rails are +8.8 V at 1.2 A, 16 V at 0.15 A and -19 V at 0.01 A (Computers Museum), so the machine cannot be run from a generic single-voltage adapter

Units sold

Unconfirmed. Computers Museum says around 20,000, including 8,000 in the US. oldcomputers.net gives about 8,000, marked as uncertain, for the US and Australia. The Register gives no sales total but says Mattel UK had hoped to sell 100,000 through WHSmith and Boots. The two figures are not independent confirmation of each other, so treat any total as a rough guess

Successors

The Aquarius II, designed by Radofin as the “Chess” project and sold by Radofin in 1984, with a typewriter-style keyboard, more RAM and Extended BASIC. It reached the market only in small numbers. A planned Aquarius III never reached volume production (The Register). Wikipedia’s infobox also lists a modern Aquarius+ as a successor

Garbled screen and no response from a failed Z80

A forum thread on AtariAge describes an Aquarius that had a power light, answered the reset button and showed only a garbage screen. The owner found activity on the address lines but none on the data lines, suspected the system ROM and a RAM chip, and in the end fixed it by fitting a new Z80. A fellow Aquarius owner in the same thread says the two ULAs and the character ROM can also fail but rarely do, and cannot be bought separately.
Just got a Mattel Aquarius, and it has issues (AtariAge Forums) →
Cassette port that fails more often than it works

The author of the Aqua cartridge, a 32 KB RAM and SD card loader for the Aquarius, describes the machine's cassette port as slow and failing far more often than it succeeds, which is why he loads from SD instead. Wikipedia adds that the cassette pinout did not match readily available TRS-80 cables, although a 1983 Your Computer review says a TRS-80 lead worked, so check the plug before blaming the port.
Aqua, an SD card and RAM cartridge for the Aquarius (Hackaday) →
Stiff rubber keys that miss keystrokes

The Register reports that reviewers of the original Aquarius found the rubber keys hard to press, wobbly and prone to missed keystrokes. Gondolin's copy of the July 1983 Your Computer review says the 49 small keys need a firmer touch than the Spectrum, mis-typing is easy and there is no auto-repeat. This is a design fault and not an age fault, so a machine with a poor keyboard may be working normally.
30 years of the Mattel Aquarius (The Register) →

1983 Shown to the public at the Winter CES in January, after Mattel had contracted Radofin to build its "Checkers" design as the Aquarius
1983 On sale in the US from June at US$160, which The Register calls dearer than the VIC-20 or TI-99/4A and Wikipedia calls cheaper, before the cost of add-ons
1983 First UK units appear in July at about £90, with Mattel UK hoping to sell 100,000 through WHSmith and Boots
1983 In October Mattel leaves the computer market and hands the Aquarius back to Radofin, and the UK price drops to £59.95
1984 Radofin launches the Aquarius II, a 36 KB version reviewed in June 1984 at about £129, but it sells in small numbers

BUYING NOW

Roughly US$65-$120 for a working complete machine on US listings (asking prices seen in search snippets for a boxed model 5931R and for an unboxed bundle, not confirmed sales). Mini Expanders, cartridges and boxed accessories sell separately for a little less. No reliable UK sold prices found. Low confidence

The power supply is inside the case, so a machine that does not power up needs opening up. The rubber keys and the cassette port are the usual annoyances. The two custom ULAs and the character ROM are hard to replace except from a donor machine, so a working one is worth paying a little extra for