SB 200

[Mark Graalman WB8JKR]

  John,

  I don't think the plate blocking cap or any other cap has
anything to do with your plate current levels. Is the
idle current about the same as it was before? (90ma or so)
 There is a good chance that these newer tubes may have
a bit more gain than the old Cetrons and in that case a simple
reduction in drive may be order. As long as the amp is in cutoff
during receive and idles around 50 to 100 ma or so when keyed
with no drive, the cutoff and operating bias levels are probably
ok. If your current still levels seem high, I would think there is a
better chance of a resistor in the plate meter circuitry having
a change in value. This is all assuming the amp can be properly
tuned, you should be at about 500ma plate I, 2000 V plate E, and
about 60 to 80 ma. grid I when properly tuned up.

Mark  WB8JKR


On Wed, 3 Apr 2002 16:37:08 EST John Barkow <KD6PT at AOL.COM> writes:
> Hi Gang.  Well,I finally got around to installing the new finals in
> my old SB
> 200.  Now I am drawing too much plate current so I suppose some of
> the HV
> caps are leaking.  Mouser has the HV ceramics but no doorknobs.
> Does anyone
> know where I might obtain one of the !000 uuf. doorknobs?  Also,
> what type of
> capacitor is used nowadays to replace the old Mica caps  There are
> so many
> new types, I am confused.  Any help will be appreciated.
> John kd6pt
>
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