[Heathkit] DX100,DX100B

[Glen Zook]

The DX-100B has only 1 crystal postion instead of 4
like in the DX-100.  There are, if I remember
correctly, 2 minor capacitor value changes in the
driver stage.  The DX-100B has the completely variable
loading capacitor arrangement whereas the original
DX-100 had a 50 pf variable in parallel with fixed
capacitors that were switched.  The DX-100B chassis
has holes to add the conversion kit for the SB-10 but
the DX-100 does not.  You have to drill holes in the
back of the chassis if you want to use the SB-10 with
the DX-100.  Of course the cabinet is different.

Heath did come out with a modification kit that
changed the fixed loading capacitor arrangement to the
complete variable.  Those transmitters that were thus
modified were known as "DX-100A" units.  That is why
when Heath came out with the newer version that it was
called the DX-100B.

There was another modification kit that added a
spotting switch to the DX-100, DX-100A, or DX-100B and
changed the keying arrangement for CW.

Still another modification kit came out to add
capabilities of using the SB-10 SSB adapter.  Again,
the DX-100B had holes on the rear of the chassis to
add the SO-239 connectors and you had to drill holes
to add the kit to the earlier versions.

The basic schematic is very similar between the DX-100
and and DX-100B.  At least 95% of the circuitry is
identical and the rest is quite obvious (except for
the capacitors in the driver stage, but the
transmitter will work fine with either the original
value or the "new" value).

Glen, K9STH

--- Robert Thompson <va3rd at rac.ca> wrote:

Does anyone know the difference between a DX100 and
the DX100B other than the case? Is the schematic the same?

Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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