I ran it for quite a while today, and I think I made some progress
towards
getting back to where it used to be. It's hitting 31.5", and it's
making a
thudding sound while doing so. It does this while running just shy of
105V. If I push it up to 115V or higher the sparks start to make a
cracking
sound in addition the the thudding. It's also at this point that
the sparks
start to branch and become shorter.
I tried lowering grid resistance and it only results in shorter
sparks, and
only marginally at that. I'm a little wary to lower the resistance
since
the accident that marked the end of the good performance I was
getting from
the coil. I kept turning down the resistance until the secondary
flashed
through the silicone sealant and ruined my grid coil. Of course,
this was
an extreme case, and foolish at that.
I did move the grid coil down to increase the coupling a little and
that
seemed to help.
On Mon, Oct 20, 2008 at 21:03, <futuret@xxxxxxx> wrote:
The throaty popping sound may be a "bad" sound meaning
the coil is not running just right. Some component may be
failing. Or the staccato controller timing may have changed
in some way. The solid thud sound is good, other types
of sounds can be bad. Is it a raspy sound? If so that's
a sure sign something isn't right. Maybe from the high
power operation of the tubes, they became damaged.
Or arcing may have been occuring in the tubes which
can make a popping sound. You can try reducing the
grid resistance to see if it helps. That tends to keep
the voltages in the tube lower and may help. But it
will make the tubes run hotter of course. But it may
be helpful just as a quick test to get an idea of what's
happening.
John
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