I saw this page which has a description for an eprom programmer:
https://www.applefritter.com/appleii-box/H049_AppleIIepromProgrammer.htm
Is there a ready made layout file I can use to order a PCB?
And is there a proper BOM list somewhere, which makes it easier to order the correct components?
You could have ordered a pcb in 1984 from Franzis-Verlag in Muenchen, West-Germany. This project was introduced in the mc 8/1984.
But times were changing :-) With the mc 1/1987 the author Peter Seng introduced version 2. The new one can programm 27512, has current control during programming, an internal power supply, and a disconnected pin 28 (Vcc) when inserting or taking out the EPROM. There is the article about version 2 including one side of the layout:
http://www.ralf-kiefer.de/A2/mc-Eprommer/mc_Eprommer_V2a.pdf
This is version 2 "upgraded" to modern chinese DC-DC-converters instead of the large 50Hz transformator:
http://www.ralf-kiefer.de/A2/mc-Eprommer/mcV2_mit_DCDC_klein.jpg
Regards
Ralf
I don't think I could have :-)
I got my Apple II europlus in 1983 or 1984 as a young guy and was not aware of these eprom programmer things back then.
Thanks for the pdf and jpg.
I have downloaded them and will look at it and decide if I will begin the task of making it.
Do you have a link for that DC-DC-converter on ebay or somewhere else?
My observation: the 50Hz transformator from the 1980s was (of course) a 220V type. In these times I often got just 215V where I lived as a student but that was in tolerance. Now in West-Germany the voltage is regulated to 230V. Actually I live in a short distance to the transformator station, means I typically see incoming 235V. That's also in tolerance. Now. But this difference of 20V is a bit stressy for the LM317 and especially the 7806.
My decision: an external power supply between 7 and 24V. The seperation of the 5V branch from the 7806 means I removed D4. One DC-DC converter is a fixed 5V type (stepdown) having exact 5,0V at the programming socket. The other is a stepup converter to power the "high voltage rail" with 30V.
These DC-DC converters are types which were available in my "storage".