[kinda-ot] Plasma ball driver HVPS

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Original poster: Richard Smith <rsmith@xxxxxxxx>

Greetings all you HV gurus.

I've been given a HV powersupply for a plasma ball with the request 
to repair it.  I've been googleing for the last few hours and I can't 
find anything similar to this design.
This list seemed like the best place to ask for some guidence.

I'm an EE but I'm mostly a uP level digital man.  So this is a tad 
bit out of the bulk of my expertise.  I have played a bit with HV in 
the past though and I'm not a total stranger to analog but I'm not 
having any luck getting my head wrapped around this circuit.

The PS uses a flyback xformer with a custom wound primary just like 
you see in all the 2n3055 designs all over the net.  The key 
difference is that it dosen't use low voltage on the primary winding.

The whole thing runs off of filtered, half-rectified 120VAC.  The 
power transistors mounted on to a heatsing are a MJ8501 and a 
D40E5.  I found data on the MJ8501 but not on the D40E5 other than 
its a high frequency NPN.  I found some crosses listed for the D40E5 
but the pinouts on them don't seem to make sense with what I see in the wiring.

I've tried to draw out most of the circut but when I get to how the 
trasistors are wired up it's confusing.  The flyback has 3 other 
parts of the coils hooked up to the trasistors.  Without the wireing 
info of the flyback and the the pinout of the D40E5 I don't have much 
of a clue how its hooked up.  Its obviously got to be some manner of 
osciliator for it to pump the flyback but its certainly non-obvious 
to this digital boy.

This apparently was some sort of kit that was purchased aound 10 years ago.

Has anyone have any idea what setup I may have or perhaps a link to 
any flyback driver circuits that drive the primary with 120VDC?

I'll be happy to go into much greater detail on what I have drawn on 
the the schematic if anyone is interested in helping me figure it out.

TIA,

--
Richard.