This page describes a EPROM programmer that is designed to operate on a SYM-1 computer.  this board is named 2708 Board because it will program  these memory types.  

The hardware is built on a Radio Shack project board catalog number 276-154.  Here is a  photo of the completed board.  The schematic shows the wiring diagram of the board. Note the transistior switching arangement was designed to meet the source and sink requirement of the 2708.  Later model chips did not have this unusual requirement.

The external voltage supplied to the Programmer should be 27.3 volts to maintain the chips required voltage during programming based on the switching circuit shown.   This voltage was generated using a LM 723 regulator adjusted to 27.3 volts.

This project was designed and built in 1982 long before I had an assembler program, so all of the code was hand assembled and keyed into the SYM from a Teletype Terminal.  The source code is avaliable in printed form and the object code is on cassette tape.  Design notes of the timing pulse and power supply are also avaliable if needed.

I have not included the additional information due to the obscurity of the 2708 EPROM these days.  If it is required, I can supply all other aspects of this project.