Computers
liamoc.net

I am a collector of old computers, particularly those used in the home in the 1980s and early 1990s. I maintain these machines and upgrade them to use modern storage solutions. I also pursue projects writing games and software for a wide variety of these machines.

Wishlist

I will be adding an Acorn A410/1 and a Panasonic MSX2 machine at some point in the coming months. I am still actively looking for the following items (in rough order of priority). If you have one you’re willing to sell/donate to me, please get in touch (me at this domain).

  • Jupiter Ace
  • Sinclair ZX80
  • Sinclair QL
  • Memotech MTX models
  • Camputers Lynx models
  • SAM Coupé
  • Sharp X68000
  • BBC Micro Master
  • Apple ][ Europlus (and other Apple II models and hardware)
  • Commodore 128
  • Texas Instruments TI99
  • Atari 5200
  • A good 486 machine. Maybe a Compaq Presario 425.
  • One of the Atari XL series machines
  • Portable devices, specifically Game Boys, Game Gears and Atari Lynxes.
  • Other 1980s micros not listed here, particularly those from the UK.

Acorn

Atom

This rare precursor to the BBC Micro was released in 1980, with the same 6502 processor, but a simpler video chip (the same as the Dragon 32 and other early micros). Because I couldn’t locate a power cable that fit, I removed the 9v voltage regulator circuit and installed a new 5v power socket that supplies power directly to the main logic board. I also bypassed the RF output and installed a wire to produce composite output over the RF jack. The system works well but I’d still like to perform more modifications to reduce screen noise and improve functionality.

BBC Micro Model B

This is the most popular variant of the BBC Micro, a computer first released in 1982. It features a blazing-fast 2MHz 6502 processor and 32KB of RAM. I also have a BBC-branded Watson disk drive and an SD2BBC installed. There is also some interWORD software installed via ROM that I haven’t messed with much. This has not needed modification or repair beyond the SD2BBC ROM installation and adjusting the potentiometer for the speaker to not be so deafeningly loud. I believe the previous owner had recapped the board already. I also have a joystick adapter installed in the back.

I also have the ROM chip for the amazingly complex (for the time and system) game Dr. Who and the Mines of Terror, as well as the disks and the rest of the original packaging. The game still works beautifully, and I imagine it is quite valuable now on account of the ROM chip.

Electron

This is a cut-down version of a BBC Micro B with a much slower memory bus and most separate chips consolidated into a single ULA chip with only one-voice sound and no Teletext mode, originally released in 1984. I also have an ElkSD128 installed in the back which gives a whopping 128KB RAM upgrade, a joystick adapter, and an SD card interface. I haven’t needed to modify or repair it at all except to re-seat the ULA which had come loose.

Apple

Apple IIc

A compact version of Apple’s famous Apple II line of computers, originally released in 1984. Like the BBC Micro, it runs a 6502-based processor but at half the clock speed. The video hardware is also more primitive, and the only sound is a CPU-driven speaker. Nonetheless I am a fan of Apple’s Snow White design language at the time, and I had played emulated Apple II adventure games often as a kid. I have a Floppy Emu to enable SD card connectivity, and a Z80 CPU expansion board, along with many disks including CP/M for the Z80 CPU, which works well. The original owner had kept this very well maintained and I haven’t needed to repair anything.

Apple IIgs

This 16-bit successor to the Apple II, released in 1986, is superior in some ways to the Macintosh. For example, it supports incredibly good graphics and sound chips. It supports a 6502-compatible 65C816 processor, like the Super Nintendo, and is the last of the Apple II line produced. I have a step-down transformer because my model came from Canada. It works great, but this is a ROM0 model so it cannot yet run GS/OS. I have ordered a ROM1 chip to upgrade it but it hasn’t arrived yet.

Macintosh Classic II

A later computer from my favourite series of Macs, the classic compact Mac design, released in 1991, with a Motorola 68K processor. Compact Macs have a very cute form factor and a crisp monochrome display with a revolutionary (for the time) UI-based system. It is similar internally to the Mac SE/30 except that its shorter memory bus makes it a bit slower and means the maximum amount of memory is 10MB. I haven’t been able to get it to turn on, and compact Mac repair is tricky business. Eventually I hope to get this one working because the chassis is in very good condition, but I haven’t been able to test the CRT for burn-in. It has a working hard drive but I probably won’t continue to use that, instead using my Floppy Emu.

Macintosh SE

A nice computer from my favourite series of Macs, released in 1987. This one works but has quite severe screen burn-in that makes the screen rather unpleasant to use. If I can get my Mac SE/30 to work, I will probably put this one into storage, but if I can’t I might take the logic board from this working machine and try to use the screen from the Mac SE/30 with it, as the analog boards and CRTs are compatible.

Macintosh SE/30

This is the most upgradeable and high-performance compact Mac model, originally released in 1989, with a nice 68K processor and is upgradeable to a whopping 128MB of RAM. There are no images for this one as it’s been taken apart for repairs. The battery had exploded and leaked fluid all over the logic board, but it didn’t seem to have actually corroded much. I cleaned it up and found a horizontal zebra-stripe pattern when powering on. I tried replacing the surface mounted capacitors, but it still doesn’t work. More investigation is required.

Macintosh LC

This is a cheap low-cost (hence the name) 68K Macintosh released first in 1990. I picked this up on the cheap from eBay, and sure enough it didn’t turn on on arrival. Opening up the computer, I found the motherboard in very good condition, but the power supply wasn’t working. The power supply had several capacitors leaking electrolytic fluid everywhere,so I quickly desoldered them. After soldering in replacements, it seemed to have returned from the dead, but the speaker made sounds like a cartoon bomb falling from a great height. Replacing the logic board capacitors fixed all the issues, but the hard drive it came with is unfortunately stone dead. It’s significantly more yellowed than the IIsi so I would appreciate if anyone wants to help me retrobrite it.

Macintosh IIsi

This is a higher-end model of Macintosh released simultaneously with the LC. The previous owner has recapped and refurbished the machine already. I’ve tested it with my Mac display adapter and it works great. It has 5MB of RAM and a 500MB hard disk. The fans are quite loud though, so I’m hoping to find a way to quieten them somewhat.

Macintosh PowerBook 1400cs

This is an early PowerPC-based Macintosh Laptop, released first in 1997. It was the first model released after the infamous PowerBook 5300. Quite a bit newer than the rest of my collection, but good for running software intended for PowerMacs, although the passive matrix display is a bit uncomfortable to use. It features 12MB of RAM and runs Mac OS 7.5.3.

Amstrad

CPC 464

This is Amstrad’s most popular home micro under the Amstrad brand name, running a Z80 processor at 4MHz, first released in 1984. While it needs a bit of cleaning and attention, it already works well with my Amstrad CTM644 colour monitor, also pictured. Even the tape deck works well. I am still hoping to acquire a SD card interface for this machine. Please contact me if you have one available.

The monitor works well but certain colour channels appear dim, particularly red, which looks more like a muddy brown. I would like to fix this but I don’t know very much about CRTs and disassembling them scares me — I would rather not get high voltage shocks from the tube! So, if anyone in Scotland has experience fixing these and wants to have a go, please let me know.

Atari

Atari 2600 Junior

Originally released in 1977 as the Atari Video Computer System (VCS), the Atari 2600 is one of the first popular video game consoles. It is based on a cost-reduced version of the 6502 processor called the 6507. It contains only 128 bytes of RAM, the rest of memory comes from a measly 4KB ROM cartridge, one for each game. This is a later cost-reduced model of the Atari 2600 colloquially called the “Junior”, released in 1986. I have an Uno cart that lets me play all the classic games and homebrew titles. Strangely my power cable, which I ordered from a UK seller, is for American voltages, but it works with my step-down transformer.

Atari 65XE

This is one of the later editions of the Atari 400/800 8-bit line of 6502-based computers. With their powerful ANTIC video chips and servicable POKEY chips for audio, they are quite good for 8-bit gaming. Architecturally, they are almost identical to the Atari 5200 series games console. The 65XE has a Atari ST style chassis and 64KB of RAM, released in 1985. Later, this would be repackaged into a game console known as the XE Game System or XEGS. This Atari 65XE was made by fusing two broken machines together. I have a second Atari 65XE in storage made from all the broken components left over. It would be nice to get the other one working and sell it, but even after replacing all the RAM and the CPU it still boots to a black screen. I also have a working Atari tape deck and an SDrive Max with a matching styled chassis.

Atari 520STFM

The most popular variant of the Atari ST line of computers in the UK, this variant was released in 1986. Like the classic compact Macs, it is based on the Motorola 68K architecture. I upgraded this with the Marpet 4MB RAM expansion and a GoTek floppy drive adapter, although I also own a significantly more yellowed 520STFM that is not upgraded at all (and, having surface mounted MMU and shifter chips, it would not be easy to perform the Marpet upgrade on that one).

This Atari ST works very well when plugged into a normal-resolution colour monitor, but not when plugged into my Monochrome Atari monitor for high-resolution UI graphics, also pictured. There, the graphics appear scrambled in a vertical stripe pattern. I know the monitor works correctly, because my unupgraded Atari 520STFM works just fine with that monitor. The Marpet upgrade is not responsible for this, as it was doing this before I conducted the upgrade (in fact, the upgrade indicates that the problem lies elsewhere than in RAM). I also tried replacing the shifter chip to see if that was causing the problem, but nothing changed. More debugging is needed.

Cambridge Computers

Z88 Portable Computer

One of the later creations of Sir Clive Sinclair, the Z88 was released in 1987, based on the familar-to-Sinclair Zilog Z80 processor architecture. Interestingly, the version of BASIC run on this device is BBC BASIC, which was used in Sinclair’s competitor Acorn’s machines such as the BBC Micro. Similarly, the built-in productivity suite PipeDream is suspiciously similar to Acornsoft’s View Professional for the BBC Micro. It features 64KB of RAM. It’s a very nice device with pleasing build quality, and being able to run BBC BASIC on the go is just great. There appears to be an active hobbyist community for this device, so I am eager to get peripherals and connectivity devices for it, to see what it’s capable of.

Commodore

VIC-20

This classic Commodore machine, released in 1980, is Commodore’s first home computing offering after the PET business machine. It features a 6502-based architecture, like the BBC Micro and Apple II, but it is significantly less powerful than either, featuring a measly 5KB of RAM. The VIC-1 display chip is also difficult to work with, but that didn’t stop many quite amazing games from being developed and distributed on ROM cartridges. This VIC-20 was beautifully restored and recapped by the previous owner, so the only upgrades I have performed is adding a Penultimate+ cartridge which adds a huge library of games, up to 35K of RAM expansion, and diagnostic tools. I also have a BackBit cartridge and adaptor for loading my own software onto it and onto the Commodore 64, in addition to an SD2IEC disk drive emulator.

Commodore 64

The Commodore 64 is the successor to the VIC-20, with 64KB of RAM, a superior VIC-II video chip and the famous SID sound chip, released in 1982. This is the later Commodore 64C variant, with an 8580 SID chip instead of a 6581 model. When I got this machine, it was sold as-is without any power supply, peripherals, cartridges or guarantee of functionality. Fortunately, it worked great when paired with a brand new power supply, except that the SID chip was unfortunately fried. I temporarily replaced it with a SwinSID nano but I was not satisfied with the results. In particular, random number generation using the noise channel does not give as good results as with the regular SID chip. Upon installing a new old stock 8580 SID chip the results are much better. I also have a Fastload cartridge and a Tapecart SD loader, which is easier for loading PRG games than using the SD2IEC, although mostly obsolete now due to my BackBit cartridge which also supports loading PRG games easily.

Commodore Plus/4

This more business-oriented low-cost Commodore computer was first released in 1984. It is compatible with Commodore 16 software, but not Commodore 64 software, as its video and sound chips are different (although it does use the same 6502 processor and similar BASIC and Kernal ROM). In some ways the video chip is superior to the 64’s VIC-II video chip, with a much bigger palette matched only by the Atari 8-bit line, but it does not support hardware sprites. Its sound chip is strictly worse than the SID, being a simple two-voice square wave generator.

My one works well. Originally the keyboard contacts were too dirty to function well, and even after applying contact cleaner and a good scrub, they required immense pressure to register on the computer. The T key stalk was also broken, but was sort-of fixed by the judicious application of superglue. Anyway, I purchased a replacement keyboard, which works very well, and the computer is now working as-new. Using the original power brick is worrisome as it can fry chips when it starts to fail. Instead, I use an adapter for my (new, reliable) C64 power supply.

Amiga 500

This is Commodore’s most famous 16-bit architecture computer, the Amiga 500, released in 1987. Like the classic Macs and the Atari ST, the Amiga is based on the Motorola 68K architecture. This model has 512KB of RAM and a GoTek floppy upgrade installed by the previous owner, who I believe also recapped the board. The owner provided a new power supply to replace the Commodore brick, but the new power supply quickly died, while the classic brick continues to work just fine. I would be interested in upgrading this with a Vampire daughterboard or other upgrades, but I haven’t had the time or inclination yet. If you would like to work together on this machine, please let me know!

Dragon

Dragon 32

This is an unusual British micro from the Welsh company Dragon Data, equipped with 32KB of RAM, released in 1982. This is essentially a clone of the Tandy TRS-80 Color Computer from the US, based on the Motorola 6809 architecture. This version works but the RF signal to the TV is quite low quality. I also have another Dragon 32 that also works, but its RF signal is nonexistent. However, I have a decent monitor cable that obviates the need for RF. One day I will try upgrading one of my Dragon 32’s to have 64K of RAM.

Nintendo

Nintendo Entertainment System

The first popular game console from Nintendo, the NES (also called the Family Computer or Famicom in Japan) was released first in 1983 and in the UK in 1987. Mine is a UK PAL edition. Mine needed a new cartridge edge connector, but otherwise works beautifully. I have an Everdrive to test it with, and a copy of Super Mario 3.

Super Nintendo Entertainment System

This is a classic games console, with probably my favourite library of titles of any console ever released. Originally developed in 1990 as the Super Famicom, this is the 1992 European PAL edition. Using the 16-bit 65C816 processor, like the Apple IIgs, it is backwards compatible with the earlier 6502 processor, allowing many NES games to be ported to it easily. It contains 128KB of general purpose RAM and 64KB of separate VRAM.

In addition to a Super Everdrive to load ROMs from SD card, and a handful of game cartridges, I also have a joystick-style third party controller, and a sync-on-luma SCART cable for clearer video. My console is in generally good condition and plays well.

I have fitted a superCIC chip to this to enable greater compatibility with NTSC ROMs and ROMs from other regions.

Sega

Master System II

The Master System, or Sega Mark III, was first released in Japan in 1985 and in the UK in 1987. The Master System II, pictured here, was released in 1990, is a cost-reduced version of the Master System that does not support SG-1000 style Sega Cards. The Master System runs a Z80 processor with 8KB of general RAM and 16KB of dedicated video RAM. My model only has RF output, but it is surprisingly clear. It features a SN76489 sound chip with 3 square waves and one noise channel.

I have no cartridges for my Master System II, as the Mega Drive’s backward-compatibility means I can load Master System ROMs on my Mega Drive using my Everdrive cart. However, my Master System II has an Alex Kidd ROM built-in.

Mega Drive

The Sega Mega Drive (or Sega Genesis) is a classic games console that was the main competitor to the SNES in western markets. Released in 1988 in Japan and 1990 in Europe, it features a Motorola 68000 processor much like the Amiga, Mac, Atari ST and other 16-bit computers (the Apple IIgs and SNES are the outliers for going with 6502 descendants). It also includes a Z80 chip for backwards compatibility with the Master System and to handle sound output. It has 64KB of general RAM, 64KB of video RAM and 8KB of Audio RAM. I have a nice RGB output cable and one controller. I have the original Mega Drive model, not the later Mega Drive II which is reduced cost. I also have an Everdrive cart that allows me to play most released titles for the Mega Drive and Master System on this device. Even more games will be playable if I mod it to support NTSC and region switching, which I eventually intend to do – however the NTSC library of games for the Mega Drive is not all that different from the PAL library, so it is less worthwhile than on the SNES.

Sinclair

ZX81

The ZX81 was Sinclair’s first mainstream home computer to sport its distinctive black chassis design, first released in 1981. Like the Amstrad machines it is based on the Zilog Z80 processor at 3.25MHz. I have had this ZX81 modified to output clear monochrome composite video rather than black and white RF output. It has been upgraded with a ZXpand+ expansion on the back, which boosts the RAM from 1KB to 32KB, SD Card interface, joystick support and AY sound. It’s a nice machine, but the keyboard is horrible to use.

ZX Spectrum 48K

The successor to the ZX81, the ZX Spectrum supports a colour display and significantly more RAM, this version supporting 48K. It was released in 1982. This “Speccie” has also been restored and the output modified to produce composite rather than RF output by the previous owner. I have fitted a divMMC Future to it, enabling SD Card connectivity and a joystick port. A classic, timeless machine which in my opinion has great aesthetics, even if the keyboard is a pain to type on.

ZX Spectrum +2

This is a later model of ZX Spectrum, from when after Sinclair was bought by Amstrad in 1986. It features a whopping 128KB of RAM and a built in tape deck. Design-wise, it resembles Amstrad machines more than earlier Sinclair machines. This machine works, but the power jack is very delicate and temperamental. It needs some restoration love and a good cleaning. Personally, I prefer the design of the earlier Spectrums, even though the keyboard on this one is a lot nicer.

Tangerine

ORIC-1

Tangerine are an also-ran in the crowded British home micro market, but the 6502-based ORIC machines are still quite capable little devices. One of my favourite things about them is the inclusion of sound effects commands in the BASIC ROM such as ZAP and EXPLODE. They are very simple devices to disassemble and tinker on. The ORIC-1 was released in 1982.

I have an Erebus SD card connectivity device for the ORIC Atmos, and it is able to upgrade an ORIC-1 to an Atmos by providing the extra ROM. While it doesn’t work on the device pictured (simply hangs) it does work on another ORIC-1 that I own.

I also have this nifty Micro Peripherals MCP-40 Colour Plotter/Printer that was commonly sold alongside the ORIC. I haven’t got the cable yet to test it out properly, but it does connect with another cable to the BBC Micro, which can print text (but not, seemingly, special control codes for graphics).

ORIC Atmos

The ORIC Atmos is essentially the same as an ORIC-1 but with additional ROM features and a nicer keyboard released in 1986. This Atmos came with a “stuck” T key because the sticky tape insulating the speaker from the keyboard circuit had worn away (Tangerine were not known for their build quality). While that is an easy repair, the N and space keys seem to be temperamental. I have tried “hot-wiring” the solder joints and it instantly registers a key press, but the keys themselves take sustained pressure to register a key press. I guess there’s something wrong with the key mechanism for those two keys, but there’s no way to disassemble the key mechanism to fix it. So I make do with a temperamental keyboard. My ORIC Erebus works well with this device.

Tatung

Einstein

This physically enormous machine is another z80-based micro, released in 1984. It features a generous 64K of RAM, an AY-3 sound chip, and a TMS9918 video chip, suspiciously similar to the MSX standard. It was also capable of running ZX Spectrum software using a special addon. When mine arrived it was so filthy I had to clean it with heavy duty products that also removed a lot of paint from the surface, but apart from that damage it looks in good condition. It powers on but generates a blank video signal on RF. I am planning to do a small mod to enable RGB output on a BBC-style cable to see if I can get a picture that way. Mine has two disk drives, but they seem to be an unusual format. Perhaps they are QL microdrives? I’m not sure.

Toshiba

MSX HX-10

This is the most popular machine conforming to the MSX standard in the UK, released first in 1984 and in the UK in 1985. Like most other Japanese micros at the time, it conforms to the MSX standard, with a Zilog Z80 processor at 3.6MHz, a 3-channel AY sound chip, 64 KB of RAM and 32 KB of ROM (both Microsoft BASIC and a BIOS). This machine has a few dings but otherwise works beautifully without any repairs. I have an SD cart with Nextor and Sofarun installed, allowing many games and applications to be played. I am still interested in acquiring a MSX cart of the game Butamaru Pants, also called Pig Mock, because for some reason that game specifically will not work with my SD cart.