[Amps] AL82 3-500 4-400

[Rob Atkinson]

The 4-400A is really designed for chimney use.  The base is made to
direct air up around the pins and out at the side of the base so it
can travel up between the bulb and the chimney wall to the anode heat
sink and out.  But the sockets in the AL-82 may not be intended for
this.  The SK-406 chimney for the 4-400A is the same one used for the
3-500Z.  So you don't need to worry about finding a different chimney.
But, you may need a flat anode heat sink if there isn't enough
clearance for the typical tall heat sink.  I am assuming you will
ground the screen with the control grid.  I'd plug in a tube with the
chimney and anode heat sink and disconnect everything except the
blower and spin it up and check for air flow before trying anything
else.  I don't know how Ameritron mounted their sockets for this
purpose--they may be okay but the 3-500 base is different from the
4-400A.

73
Rob
K5UJ