Posts by Richard Zealley
Sinclair ZX81
The ZX81 was the successor to the ZX80, still based on the Zilog Z80A but with 8K ROM rather than 4K, and the same 1K RAM. The biggest technical difference was the integration of many of the ICs into one component, which reduced the chip count and the cost, starting at £49.95 for a kit, and £69.95 for a ready-built machine.
Read MorePsion Series 3mx
The Psion Series 3mx was the last model in the Series 3 line, launched in mid 1998, and is an upgrad to the Series 3c. The main differences are: a silver metallic finish, a CR2025 backup battery, and a faster processor, the 16 bit NEC V30MX (80C86 compatible) running at 27.684 MHz. It has a backlight like the later models of the Series 3c.
Read MorePsion Series 3c
The Psion Series 3c followed on from the Psion Series 3a and predating the Series 3mx. The main differences are: a redigned case in black with a rubberised coating (that degarded into a sticky mess over time), an infrared port, and a backlight (on later models).
Read MorePsion Series 3 Software
My collection of Psion Series 3 software on SSD.
Read MoreTowers of Hanoi for Sinclair ZX81 in 1K
My one claim to fame – a short program I submitted to Sinclair Programs magazine in 1983. I was shuffed with this because I’d managed to cram it into just 1K. I hadn’t yet invested in a 16K RAM pack.
Read MoreTandy WP-3 Word Processor
The Tandy WP-3 is a portable Word Processor from the lates 1980s, early 1990s, a successor to the Tandy WP-2 but with a British English dictionary. Based on the Z-80 compatible NEC 70008A-6 it had a 6 line LCD display and a very usable full-size keyboard. Powered by 6V main supply and/or 4 x AA battries with backup from a CR2340 cell.
Read MorePsion Series 3mx SSD door microswitch repair
I recently bought a Psion Series 3mx on eBay but found it didn’t recognise SSDs inserted in either A or B slots and suspected a motherboard fault. Having found a cheap 3mx to test this, and checking that it did indeed read SSDs OK, after swapping the motherboard it didn’t help. Not only that but it also failed in the same back in the original machine.
Read MorePsion Series 3 – New Arrival
My existing Psion 3 was suffering from a faulty screen so I’d been on the lookout for a replacement/repair and found this on eBay, boxed with manuals, and it arrived today.
Read MoreSharp PC 3000
The PC-3000 was a DOS-based computer, the predecessor to the PC-3100, launched in 1991 following the release of the Atari Portfolio, the world’s first palmtop computer.
Read MoreTexas Instruments TI Programmable 57
The TI-57 was a programmable calculator made by Texas Instruments from 1977 to 1982, which was followed by the more powerful TI-58 and TI-59. It had 50 program steps and 8 memory registers. I owned a Texas Instruments TI-57 while at university, used very occasionally for ‘real’ problems but mainly just played with the examples…
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