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SiriusHardware · 18th May 2021, 8:08 am

I thought maybe around 8-9V, based on a compromise between excessive volts drop across the 5V regulator and the need to have a bit of overhead on the input so the regulator can always regulate. It may be a low-drop regulator but not intentionally so. But then why is the input protection diode >= 18V? Maybe to guard against accidental connection of the +30V supply to that supply input terminal.

It's fun to speculate on all this, but when onewatt comes back maybe he will be kind enough to measure the PSU voltages.

18th May 2021, 8:08 am	#89
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,556	Re: Early EPROM programmer. I thought maybe around 8-9V, based on a compromise between excessive volts drop across the 5V regulator and the need to have a bit of overhead on the input so the regulator can always regulate. It may be a low-drop regulator but not intentionally so. But then why is the input protection diode >= 18V? Maybe to guard against accidental connection of the +30V supply to that supply input terminal. It's fun to speculate on all this, but when onewatt comes back maybe he will be kind enough to measure the PSU voltages.