Thread: 4CX1500B
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Old April 24th 08, 12:23 AM posted to rec.radio.amateur.homebrew
Harold E. Johnson Harold E. Johnson is offline
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First recorded activity by RadioBanter: Aug 2006
Posts: 154
Default 4CX1500B


"K4ERG" wrote in message
. ..

Bottom - - Heater
Next up - - Heater and cathode
Next up - - Grid
Next up - - Screen

Ah! Bless you "Erg". The ONLY thing I could find was as you state for a very
old (45 years) copy of a 4CX1000 data sheet. Even Google was befuddled.

It makes sense to me (And to the builder of the not quite finished amplifier
that I inherited) that Eimac would put the lowest potential terminal at the
bottom. And then proceed to the screen. Obviously, they had something else
in mind.

Wired with the bottom ring to ground, making the cathode 6 Volts AC above
ground gives rated power out, but about 200 Watts of it was 60 Hz hum. The
task of making the change is pretty daunting. Not impossible, just daunting,
and I wanted to make certain that this was where my hum was coming from (31
Volts of bias, ~25 of DC and 6 of AC) before I removed half the amplifier to
get the sub-chassis out.

Tnx again.
W4ZCB