Apr 11, 2017 i think due to the address decoding, the ram in the zxpand has to be mapped as a block from 16k48k, which is the default. An anonymous reader writes the zx81 museum was setup to preserve and showcase a private collection of. The zx81 has a base configuration of 1 kb of onboard memory that can officially be expanded externally to 16 kb. There is information about all the items, including inlay and instruction scans, screenshots, listings and the. Zx81 ram pack schematic diagram ts1016 equivalent ts1016 user manual. Also the ram pack contains some voltage conversion circuitry that gives problems in many cases, and those 4116 rams are nasty critters in general and 30 years old. The zx97lite is a simplified zx97 designed to fit on one single sided pcb. Collection of articles and tips for zx81 19811986 showing 18 of 8 messages.
Sold in both kit form and assembled, only two official perhiperhals for the zx81 were released. The ram wr, data and address lines are also connected to the corresponding. Sinclair zx world about the sinclair zx80 and zx81 home. It is designed to be mounted on a small piece of perf board with feedthrough pcb connectors to plug into the rear of the zx81. Keyboards and keyboard accessories for the zx81 and ts. Due in part to the inertia behind discussions on the sinclair zx80 and zx81 discussion forums, various items of software have been released for the sinclair zx81 over the past few years, utilising the best tools on pcs in order to create imaginative software, which. Resources for the sinclair zx80 and zx81 home computers. The ram pack was topheavy and was supported only by the edge connector. You needed an interface board that sat between the zx81 and the ram pack, which provided two interface slots for the addons. But zx1541 also has own input romcs on schematic it is called disin, that forced to high disables all zx1541 memory and then zx81 rom, too.
Ram packs and memory expansion for the zx81 and ts. Pinball and fortress of zorlac are my mostwanted right now. Config zxpand manual config config x config xy press shiftg in k mode replaces llist command the config command is the main method of communicating with and configuring the zxpand interface. Sinclair io board completed over 30 years later hackaday. As the schematic shows the ram pack doesnt use romcs in any way. Minesweeper is written by zxteammember bodo in pure basic. The zx81 basic programming manual, also available in pdf format the timex computer 2068 portuguese user manual the timex 1016 16k ram pack schematics for the zx81 or ts. There were long waiting lists if you ordered it via mail order which for sinclair products was common at that time. Zx81 sinclair 16k ram pack aka timex 1016 board schematics. Most visitors to our beautiful isle know to behave themselves, treating the locals with respect and admiring the scenery.
Attribute colour mode 15 ink and 15 paper colours per character position. It was very difficult to get in the early days after its release. It had a habit of falling out of its socket at crucial points and crashing the zx81, losing anything that the user had typed in. Home periodicals sq syntax quarterly 16k ram pack schematic. The device attaches to the expansion connector and is powered by a small external supply. If you can unsolder ics cleanly, internal ram expansion is easy to do. The memory is provided by either a single 4118 1024 bit.
Ram projects include m1 decoding but i think you will like my my favorite circuit for this application using the 74hc251 as shown below. The zx97l is a complete zx81 using discrete logic chips with 32k of battery backup ram and 32k of eprom. The sinclair zx80 was one of the first real home computers it was supplied in kit form to home electronics enthusiasts for just. Sinclair responded by launching his own halfprice deal, offering schools the chance to buy a zx81 and 16 kb ram pack for. Ugly as sin, and made the ram pack wobble problem different, but as i added an external keyboard to mine, complete with power switch and reset button, i did not have to touch my zx81 at all. With basic you will have modified and new zx81basic commands. Softwareexchange i improved the 3dlabyrinthsoftware. Corrections to problems with the 16k ram pack schematic printed in sync 1. Absolutely stable, and with larger surface area they ran cooler to boot. In case it disappears from the internet, here is a local copy 1. You could only get a reliable performance out of the zx81 if you stood a carton of cold milk against the ram pack it acted like a big heat sink and stopped the little. This web site contains my own collection of zx81 and ts tapes, hardware and books that i have built up over the last ten years or so, almost entirely from buying items on ebay, along with a small number of kindly donated items. Jul 22, 2014 in this state, it can be used fine with a ram pack, and so is an option to leave it like this. Here you will find the contents of memotech memopak booklets for addons for your zx81.
Sinclair started selling the zx81 on the high street via w h smith. View and download sinclair zx81 user manual online. Due in part to the inertia behind discussions on the sinclair zx80 and zx81 discussion forums, various items of software have been released for the sinclair zx81 over the past few years, utilising the best tools on pcs in order to create imaginative software, which is up to or exceeeds the standard of previous commercial releases. The timex sinclair ts was the first computer produced by timex sinclair, a joint venture between timex corporation and sinclair research. I think due to the address decoding, the ram in the zxpand has to be mapped as a block from 16k48k, which is the default. As the schematic shows the rampack doesnt use romcs in any way. Use eightyone in zx81 emulation mode with no ram pack or 2k ram pack use fileopentape to open the life. The original sinclair branded zx81 ram pack used 8 x itt41164d dram chips along with address and refresh circuits. Ive got a couple of timex s, a usa zx81, a couple of memotech 16k ram packs, a timex 16k pack, a timex printer, and 1215 cassettes. Home periodicals sync schematic of sinclair 16k ram pack. All it uses are data lines, address lines to be multiplexed and associated control signals. The zx81 offered 1kb of memory and an 8bit cpu with a speed of 3. Among the most popular, and as equally required, accessories were the 16k ram pack and a printer. The modification to swap d0 and d1 on the edge connector it is probably easiest done on the back of the board, cutting the tracks at convenient points and wiring the vias to pins on the ram socket.
Recoil retro computer image library decodes amiga, amstrad cpc, apple ii, atari 8bit, atari portfolio, ata. Cpu, rom, ram and ula a custom logic chip that incorporated all functions of 74xx logic of zx80. The zx81 was never designed to make use of a file system and this should make finding the file you want much easier. The best ram packs for the zx81 were the dktronics line. Minesweeper for your zx81 will also run under zx81emulator xtender. That bit is enough to have the memories flooding back. Not much, and the ula was most of the glue the machine needed. Ive even got a zx80 pal as far as i can tell that was heavily modded by the original owner and is pretty roughlooking. The romcs line disables rom inside zx81 when is forced to high state. Nov 21, 2016 the zx81 had 4 chips z80, sinclaircustom ula, 1k ram, 8k rom, a couple of dozen passives, and maybe a quadnand or something for glue. Download software for zx81 and emulator here i will present some nice software for your zx81 which is written by zxteam members and cannot be found in other sites. Currently the enhanced version will work on the eightyone zx81 emulator for the pc, as well as the sz81 emulator version 2. There are also some zx81 book cover scans, and some hardware photos and manual scans, including the the dktronics 4k graphics rom, complete with a dump of the rom, circuit diagram and fitting instructions, and a description of the ts1500 composite video modification. Z81 a zx81 emulator for vga pcs running linux xz81 a zx81 emulator for x z81txt a textmode zx81 emulator for the linux console.
It used a standard cassette recorder and black and white television. One year later, they released the new and improved zx81. Users turned to using sticky lumps of chewing gum, doublesided tape or blutack to cure what became known as the ram pack wobble problem. Sold in both kit form and assembled, only two official perhiperhals for the zx81 were released a 16kb ram pack, and the zx printer. Does away with the infamous ram pack wobble, supports true hires, and keeps the edge connector free. Zx81 internal 16k ram here we have a zx81 with an unusual ram chip. Instead of being a vertical box, they were shaped to fit the rear of the computer and came with a velcro pad to secure the far end. The sinclair 16k ram pack gives the computer sixteen times as much memory as it has in its unexpanded form. An anonymous reader writes the zx81 museum was setup to preserve and showcase a private collection of original sinclair branded zx81 hardware, software and literature. Prism vtx5000 modem this modem was designed to sit underneath the original zx spectrum, and is styled to match this system. The zx81 has the same microprocessor and runs at the same speed as the zx80, but it has a better basic programming language and is cheaper to produce, due to having fewer chips and a. The modification to swap d0 and d1 on the edge connector it is probably easiest done on the back of the board, cutting. Download if you do not want to read the booklets online. Basic is an acronym for beginners allpurpose symbolic instruction code.
Emulating a zx81 in july 2011 i discovered eightyone, a quite comprehensive and functional emulator for a wide variety of old sinclair computers, including the zx81. The zx81 has the same microprocessor and runs at the same speed as the zx80, but it has a better. This is the zx81 16kb ram pack in its original packaging. This is not that kit, this is a brand new minstrel issue 3 computer, that happens to be an enhanced reworked zx81 clone with 32k ram. Minesweeper for your zx81 will also run under zx81 emulator xtender. Its single circuit board is housed inside a wedgeshaped plastic case measuring 167 millimetres 6. However, the zx81 board has positions for various configurations of ram, 1k or 2k 24 pin as fitted or 28 pin. Page 66 the ultimate cure for this is to buy a ram pack, which fits on the back of the computer. It is a mk4801ap5, a 1k static ram made by mostek not to be confused with mos technology owned by sinclairs arch rivals commodore. The memory was provided by either one 4118 chip or two 2118 chips. A zx81 connected to sinclairs official peripherals the notoriously wobbly 16 kb ram pack and the zx printer. The zx81 had 4 chips z80, sinclaircustom ula, 1k ram, 8k rom, a couple of dozen passives, and maybe a quadnand or something for glue.