Warning:
Kitchen table project.

I have now started a project which involves a '51 MCU. For some reason I have been saved from the curse of a '51 so far. Now that I got them for free I finally can afford to try these out.

I have a Versa MIX kit which I can use for code and toolchain prototyping. No worries in there. Well - maybe I could make some use for the protocol they use for the ICP programmer dongle to avoid setting up a Window$ machine for this purpose.

This project has to do with my hobby. I do vintage radio repair and restoration. Those contain vacuum tubes of which I have collected all too many.

Many of those tubes are in unknown condition. So I need a system, other than the AVO which I have, to test these. A tube tester that is.

The first part is the filament supply which is basically just another power supply with voltage and current control. Voltages range from 0.5 to up to 100 volts. The current can vary from milliamperes to several amps. So the specs for this supply are very demanding.

You can find the schematic in here:
GIF(95kb)
PNG(84kb)

Die datenblatt for the VMX1020:
All Documents there were on the CD's
VMX8020 Data Sheet PDF.

If You have any suggestions or comments I would really appreciate those.

Thanks in advance !