Power Cube
A picture story...
Why…?
The Burroughs plasma display power supply (PSU) has become scarily unpredictable.
I could have replaced or rebuilt it, but this work wouldn’t support other projects. Amongst other things, I want to try the 8 line plasma panel as a stand-alone unit. I’ll need the flexibility of an external PSU with DC outputs of +5.1, +12, +30, +250, -12, and -250 volts.
I thought this would be a straightforward project. It wasn’t.
The problem
Full wave rectifiers. I wanted to ground at both G1 and G2, because floating voltages of 100+ DC are not human friendly. But to do this would short out diode D4.
The Answer
Half wave rectification. And some big capacitors. Simpler and more robust than using diodes to try to isolate separate rectifier circuits and their connected equipment.
I had no regulators for -12 and 250 volt outputs. Cue some potentiometer and resistance box experimentation under load.
24 volts AC produces uplifted 35 volts DC output when rectified. Useful here, because a 40 volt DC maximum for input to the step down regulators rules out the 48 volt tap on T3.
Getting started
Well hello, dolly…! Power Cube has wheels.
Components gathered...
Ply offcuts with matt blackboard paint
Aluminium angle and solder tag strips
And some scrap white acrylic for fascia panels.
Angles
On the left, resistance box. I also use this to discharge hot capacitors which may lie in wait for hours with a 200 volt zap for the unwary. Power cube’s lettering is all protected by clear vinyl adhesive film used for book jackets. On the right my original full wave rectifiers, laid out to help a 69 year old do the wiring.
Chewing Gum
When you drop an M3 bolt down the edge of a transformer, chewing gum is your new best friend…
Complete
Components and circuits installed…
AC side power on…
DC side ready…
And a test using +5 +250 -12 volts to power the single line self-scan, and +12 for the Arduino Uno…
And a short video sequence with some blinky light action. This may not play from certain platforms.
Next, let’s see what, if anything, can be done with the 8 line panel. Frustratingly, I failed to find any application notes for my version, so I’ll use an Arduino Mega to help identify the data pinouts on its 37 way connector.
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Paul, have you ever considered sharing your knowledge and experience on Gumroad?
hey my friend, have a wonderful weekend , thank you for encouraging me by liking my post, obviously i don't get this technique )