813 VTTC Lives!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Chris Fanjoy" <zappyman@xxxxxxxxxxx>


It was a long wait, but my VTTC finally came to life late last night. 
The results were far from perfect but still a good start. With only 
the half-wave recitified output from the MOT, with no voltage 
doubler, it achieved sparks of about 3-4". Obviously some tuning and 
other work is needed. The biggest problem though is with the staccato 
controller. When drawing sparks of less than 1/2" length, the 
controller worked as it should. But if I drew any sparks longer than 
that, the output would stick in continuous wave. My guess is that 
energy from the coil is somehow getting to the gate of the TRIAC, 
causing it to stay turned on. I'll try installing some shielded wires 
first and see if that helps.

Thanks for the advice, and any further comments would be welcome.


From:  "Tesla list" <tesla@xxxxxxxxxx>
To:  tesla@xxxxxxxxxx
Subject:  Re: 813 VTTC Problems
Date:  Tue, 30 Aug 2005 17:51:12 -0600
>Original poster: "Chris Fanjoy" <zappyman@xxxxxxxxxxx>
>
>
>Not to worry, I noticed that mistake myself but just didn't bother
>to point it out. Just wish I'd be that alert at more important
>times....
>
>I'm going to try connecting the G1 and G2 together ("triode
>connection"), and the G3 at ground, and see what happens. I recently
>received some TDK UHV-6A caps so this should at least provide a
>reliable tank cap if nothing else (my homemade MMC was no good...)
>
>-Chris
>
>
>From:  "Tesla list" <tesla@xxxxxxxxxx>
>To:  tesla@xxxxxxxxxx
>Subject:  Re: 813 VTTC Problems
>Date:  Tue, 30 Aug 2005 11:41:51 -0600
> >Original poster: Ed Phillips <evp@xxxxxxxxxxx>
> >
> >"    How exactly should the G2 and G3 grids of these tubes be
> >connected
> >to the circuit? And are they actually supposed to draw current?
> >     Thanks for any advice."
> >
> >         If you're using them in the pentode configuration you
> >should tie
> >g2 to
> >the filament (preferably to the center tap of the transformer but
> >not
> >essential).  I haven't bothered to look at the data book but the
> >screen
> >grid (g2) can draw plenty of current.  You didn't mention the grid
> >(g1)
> >bias when you did this experiment.  Tubes are probably undamaged.
> >
> >Ed"
> >
> > Grid 3 to the filament.  Grid 3! Grid 3!Grid 3!  Just proves the
> >need
> >for proofreading before hitting that enter key!!!
> >
> >Ed
> >
> >
>
>
>