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Re: [TCML] Rebuilding VTTC

Hi Chris,
>More is better here. For level shifter. As long as you meet voltage
requirement, which you do...


>This is necessary to protect the level shifter diode and protect the HV
plate transformer/MOT
>This is necessary again to protect the filament transformer.

I probably should have known this 0:D


>That said, this is a "tougher tube" graphite plate which also can handle a
little bit more current also.

Yes!  My old 811 tubes automatically installed cooling vents into themselves... :D


>On your paper, you mention C6 which is also parallel with R1 in the grid
leak section. You say this is a RF blocking capacitor on your paper
grouped with C4 &5. It is actually charging up here and the parallel
resistor is controlling the "leak down rate".
>So C6 is not a blocking capacitor here. In conjunction with R1 it switches
the tube "on & off" at the right time to control the plate current pulses
to the "tank".

I think I see now.  This allows the Grid to oscillate while still keeping it under control.  I never understood this part at all before.
I bought this coil like 20 years ago on Ebay and it has always worked very well.  But I really don't know how it works so I thought I would fix it up and figure it out now.

I actually have a computer simulation of it going now.


It's very preliminary but it sort of runs and allows me to fiddle with things while I learn.  After messing with the model I refined the values and it should actually be running at 407kHz.
Antonio's INCA program was super useful!


I got the secondary measurements all wrong since it was installed in the coil and very hard to measure in place.  It is actually 800 turns of #27 wire and the INCA program found this error right away!

So I think I am off to a good start figuring this coil out.  :)

Thanks so much for your help!

Best Regards,
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