Need a flexible source of high-voltage at a good price? Here’s build notes & pictures of the Eastern Voltage Research Universal Flyback Driver Kit. I ordered this kit along with several others (which I’ll be covering later) from Dan McCauley. He’s been great to deal with, and very helpful. Here’s a picture of the kit parts (NOTE: The flyback isn’t included, and I’ve already wound the gate transformer):
The manual is very good and easy to follow. I’d like to emphasize (it’s in the manual too), that if you have a biomedical device, like a pacemaker, DON”T USE THIS KIT. I strongly suggest that you read his Terms Of Sale before buying/building any of his kits. Be sure to read his Kit Difficulty Guide; some kits come only with a schematic and parts (no instruction manual), so you will need experience in electronics assembly and debugging for those kits. But that’s not the case for this kit, so let’s get on with the show!
Here are a few notes on things I found on my build journey:
On page 16, assembly step 19, installation of C1; it’s mentioned that “C3 has polarity”; it should be C1.
On page 22, Set-up and Testing step 3, the sentence “verify that you can adjust this voltage from TBD to TBD volts by adjusting R4.” – I could adjust mine from .5 <= volts >= 32.
In regards to page 14 and the special rework, step 29, it should mention that the 2N3904 (collector) needs to be soldered on the top side of the circuit board since there is no “underneath” for that one pin.
Steps 39-41 (page 19) reference a “self-adhesive” thermal insulator. The pink “band-aid” like insulators I received had no adhesive surface, but they slip between the MOSFET’s and the aluminium chassis just fine.
I made a note on the circuit board that the potentiometer has to be adjusted Counter-Clockwise (CCW) to increase the frequency. Adjusting the output voltage is done with the potentiometer near the top of the board.
As an application note: When I hooked the primary of my old Penn-Tran flyback transformer (FBT) up to the flyback driver, the maximum output voltage I could get was 750V RMS. I then created a new primary by wrapping five turns of 12-gage wire (in picture) around the frame, and with tuning, I was able to get 6,000V RMS. I noticed that tuning was very critical, and it was easy to miss the highest output voltage by adjusting the frequency potentiometer too fast.