Micro Professor EPROM programmer. By Lee Davison.
Introduction.

This is the EPROM programmer that went with the Micro Professor. For some reason all of these that I've ever seen had too small an inductor in the Vpp generator circuit, as a result the switch mode regulator chip always ran too hot to touch. On the one pictured the inductor has been changed for one about 15 times the value and now everything runs cooler.

This board has also been modified to replace the three 2k RAM chips with an 8k Dallas Smart RAM.


Images.
  • View the circuit, sheet 1 of 3.
  • View the circuit, sheet 2 of 3.
  • View the circuit, sheet 3 of 3.
  • View the EPROM pin assignments.
  • View the keyboard overlay. (480k jpg)
  • Download all the diagrams in one zip file.
    • Last page update: 8th May, 2005. e-mail me