> This, surely, will the make the grid rise (positive),
> fully saturating the tube, valve, bottle thereby shunting
> HV to ground via the cathode, blowing the primary
> protection.
That's a slow boat to China! First it has to dump all the
energy of the supply through the cathode,
then it has to ramp primary current up to fuse meleting
levels while all that energy is duming in the cathode
circuit and perhaps even back through the input to the rig.
> What damage to the grid (the most delicate electrode)
> occurs during this 'event' <might> be less with the above
> devices fitted (select your preferred order) rather than
> tying the grid to ground with a solid strap.
Why would the grid be less subject to damge? It is the first
thing in line.
The only thing a grid resitor does is allow the fault to
shift to the cathode for a new wave of destruction.
> I use R's, I've got 1985 full o/p 3-500's, once in a while
> there's 'pop', I swear, fit new R's, a fuse and am back
> on the air in 15 minutes with the same bottles.
Too bad you didn't just ground the grids and install a fault
limiting resistor in the supply positive lead. A high
voltage surge rated 20 ohm resistor would hardly allow a pop
to be heard, and you wouldn't even have to take the cover
off to repair it. Just reset a breaker and away you go. The
real advantage is you don't risk dumping all the nasty stuff
back into the cathode circuit.
73 Tom
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|