If you already have many of the components for the kits, you can save some money by buying bare circuit boards. The various kit instructions have complete parts lists for each kit. I buy the parts from Jameco Electronics, and you can buy any parts you might be missing from them. If you have any questions about the exact parts you need, contact me and I will help you pick the correct parts.
This is a "wall wart"-style power supply that produces 2000 mA of current at +5V DC regulated, which is adequate for running the computer with the display attached. It has a 6-foot cord for the +5V output with a plug that fits the power-in jack on the computer kit board. It has a USA-style plug for the electrical wall outlet. It needs an input of 100 to 120 V AC, at 50 to 60 Hz. If you are an international customer, please check if it will work in your area before buying.
This is a simple plug with leads that fits into the power-in jack on the computer kit board. It is for hobbyists who already have a power supply capable of at least 2000 mA current at +5V DC regulated (a 10-watt supply) for running the computer kit and attached boards.
EPROM price: $4.50
GAL price: $3.15
The computer kit and the disk and memory expansion kit need programmed EPROMs, and the disk and memory expansion kit needs a programmed GAL (generic array logic) IC. These are supplied with the full kits, but if you buy the bare boards and use your own components to build the kits you will need to program your own EPROMs and GALs, or you can buy pre-programmed EPROMs and GALs here. The v.7 EPROM has the code that allows you to test the computer system, and load and run small programs you write yourself, and use the Serial Interface if you have one. The v.8 EPROM has code that allows you to operate the Disk and Memory Expansion. There is an optional Tiny BASIC EPROM that can be used with the computer with the serial interface attached. The disk and memory GAL has a logic array programmed into it that operates the memory configuration logic.
The EPROMs are the UV-erasable type, with a little window over the silicon chip, meant to allow the UV light access to the chip. However, it also allows you to see the chip. Look at it with a strong magnifier and you can see the detail of the circuit, and the tiny wires that attach the chip to the package pins. I ship the computer kits with these EPROMs because seeing the bare integrated circuit is part of the educational purpose of the kit. For those who have EPROM erasers and programmers, you can change the programs if you want. The complete program listings of the v.7 and v.8 EPROMs can be found in the computer kit instructions and the disk and memory expansion kit instructions respectively. You can download the v.7 ROM files from these links:ROM v. 7 assembly language file
A full archive of ROM files, including Tiny BASIC can be found here.
I can sell other individual parts for the kits on a cost-plus basis. I have made custom ribbon cables that allow one to operate the computer with both the bus display and serial interface attached at the same time. I have also sold an "original" disk and memory kit with the memory configuration logic array implemented with discrete logic ICs instead of a GAL. I can also sell assembled and tested kits. Please contact me if you have any special requests and I will do my best to accomodate you.