Plans to expand 1K model to 16K or ZX81 with 16K to 32K for under $30. Fits inside ZX81. Gold-plated connectors and power LED. Manufactured by Indescomp. Internal RAM expansion for keyboard. No enclosure RAM pack. Expansion for the Compu-board system. Available with or without a case. Works on Sinclair power supply.

2023年3月8日 · I recently got an old Sinclair ZX 16K RAM pack with no case and 7 out of 8 ram chips and ULA etc. I checked the ram chips, they all work and if the ULA also works there'll hopefully be 16K of ram. The PCB tracks need a lot of work and it seems to have had a major power event causing the 1N4148 diode leg to overheat.

2012年5月3日 · When connected to my zeddy, the screen is fuzzy or blank. Here are samples of what I get : Are there known failures with this particular hardware ? Is there something to look at with an oscilloscope ? I already unsoldered all the RAM chips from one board and tested them into another computer, there are all good. I have also checked the voltages.

2024年11月23日 · They act as seven electronic change-over switches (the eighth will be unused). The 74LS00 NAND gates (four gates, each with two inputs) will be for the address decoding and control logic. The NE555 is likely being used to help produce the …

2024年11月23日 · Most RAM packs use 4116 or equivalent DRAM chips, which are 16K x 1 bit, so eight are needed. These most-common chips require 12V, +5V and -5V. This was before the 64K chips arrived which only required 5V. The ubiquitous 16K RAM pack, designed -- as with most Sinclair products -- for economical manufacturing, low part cost, and compact packaging.

Full-size, full-stroke, 53 key, fully assembled, gold contact keyboard for all Sinclair ZX80/ZX81, MicroAce, and TS 1000 computers. Full-length space bar and 2 oversized shift keys for easier typing. Includes plans and schematics for three special circuits you can build to utilize the 12 extra keys: electronic shift-lock, automatic repeat ...

The ZX80/81 16K RAM pack used two PCBs joined with a connector in the middle. I'd initially assumed this was due to reuse of the original 3K RAM pack case (which has a single PCB and uses static ...

The ZX80 came with a 4K ROM built-in which held the BASIC interpreter, and 1K RAM, expandable to 16K. Offered in kit form (£79.95) or ready-built (99.95), it was the first home computer to hit the sub-£100 price.

2020年10月5日 · Cette extension permet d'ajouter 32 Ko de RAM au ZX81 pour porter la RAM utilisateur sous Basic à 16 Ko et permettre l'affichage en mode graphique HRG. Le résultat affiché, 32768, correspond bien à 16 Ko de ROM plus 16 Ko de RAM.

2025年2月23日 · The ZX80 was Sinclair’s first computer sold in the United States. Launched in June 1980, the ZX80 was notable for its size, weight and price. At 7″ x 9″, weighing less than a pound and priced at $199.50, it was the smallest, lightest and least expensive home computer available at the time.