10-02-2020, 03:14 PM
(This post was last modified: 10-02-2020, 03:21 PM by ppppenguin.)
That's looking better. Main 27V rail at about 20V (won't go any higher at the moment for some odd reason) and about 15V from external PSU on LOP. Takes just over an amp which feels right. The moire patterning that's making the scan lines look like twisted rope are an artefact of compressing the JPG file. Looks a lot better on the full size file and better still on the screen. EHT is a comfortable 13kV or so.
I'll need to look at how to make an approx 15V supply from the 27V rail. I think they will need to track to some extent. Crudest method is a watty resistor. Might just work. Next would be a chunky zener or two. Or even a long string of silicon diodes. Another way is a power transistor with its base dirven by a potential divider from the 27V rail. That's probably the nicest method. Possibly a darlington so it's easy to use a pot to set the LOP supply voltage. The transistor will be dissipating around 10W so it will need to be attached to the case, along with several other power transistors.
I'll need to look at how to make an approx 15V supply from the 27V rail. I think they will need to track to some extent. Crudest method is a watty resistor. Might just work. Next would be a chunky zener or two. Or even a long string of silicon diodes. Another way is a power transistor with its base dirven by a potential divider from the 27V rail. That's probably the nicest method. Possibly a darlington so it's easy to use a pot to set the LOP supply voltage. The transistor will be dissipating around 10W so it will need to be attached to the case, along with several other power transistors.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
