more tube coil mayhem :)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hiya all!
    this quad 833 coil is a real project/PIA/hpadache/adventure.  
 
 The problems I have to deal with at this moment
    low plate voltage.  I'm going to use a doubler first off on both MOT's,
later on I'll try 2 mots in series on each 240v leg.  time to go MWO
scroungeing. 
    Filament tranny - the secondary gets burning hot, too hot. THHN melts it's
insulation and *BOOM!*  Got to wind a suitable filament tranny.  40A cont duty
is a lot of current. 
    Nasty 1.8mhz and 735khz parasitic oscillations.  The 1.8mhz were damped a
lot by adding a ferrite core choke to the plates.  The 735khz oscillation is a
mystery.  I can't pin it down, so I don't know where to try eliminatinig from.
There's of course a strong 60hz hum (from the filaments, but that's not causing
my any trouble).  But that 735khz is really tearing stuff up, and it's pretty
strong (about 1/3 the amplitude of the 423khz main driving frequency).  It
doesn't make a whole lotta sense.  Could a high Q primary be the cause of
this?  (somehow fixing network servers doesn't help me with working on tube
coils....) 
 
 Also!  How do I use my sig gen and scope to find Fres of an LC circuit? (tank
circuit).  What do I look for, and how do I hook it up?  Scoping secondarys is
easy.  
 
    
     
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Shad (Sundog)
G-1 #1203