RE: 5CX1500s:
I have eight 95% pulls ( ran at 2100 carrier out, and pulled when
emission dropped to 2000 out@100MHZ ) and three or four unopened NIB
Eimacs and three SK840s. The socket is refered to as a "ring and
breechblock".
I have seen construction articles where a hole is cut in the chassis
and a 4CX or 3CX is placed in the hole and a marker is used to outline
the grid tabs and then the chassis is nibbled away creating three
chassis tabs to match the grid tabs when the tube is turned 120 degrees.
Problem with the 5CX is that the tube's suppressor grid is a solid
ring all the way around the tube which will block the air flow unless
additional air holes are provided ( much like the SK-840 socket ). And
you will need to copy the special 5CX chimney thats wider at the
bottom to capture the air and redirect it through the anode cooler. (
SK-806 )
This will create higher back pressure than the 3CX or 4CX series tubes.
It's not uncommon to see a commercial transmitter using a single Rotron CX-33
to cool this tube at 100% duty cycle.
http://www.recycledgoods.com/products/Rotron-027556-Centrimax-CX33A33C-Cooling-Fan-Blower-200-230-Volt.html
If you already have a 4CX series socket, you could sub-chassis mount
it if you were very careful with the suppressor grid to screen grid
spacing. ( so as not to stress the tube's ceramic-to-metal bonds. The
SK 840 socket uses a low tension 360 degree silver plated spring to
contact the suppressor grid ring.
Don W4DNR
Quoting Carl <km1h@jeremy.mv.com>:
> The ring is the suppressor grid which is grounded, this is a full pentode.
> The screen, control grid and filaments are the tabs from top to bottom.
>
> Carl
> KM1H
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