[Heathkit] Building for Pleasure

[Michael D. Harmon]

There are some multi-band radios out there that claim to be kits, but 
the "assembly" consists mainly of installing boards and plugging in 
connectors.

There's just nothing like heating up the soldering iron, getting out the 
wire cutters and needle-nose pliers and building a REAL kit!

Several months ago, I picked up an old DX-40 in real need of TLC for 
$25.   Over the course of the next 5 months, I tore it down completely.
I've always had somewhat of a soft spot in my heart for the DX-40, I 
guess because it was my first Novice transmitter back in the Sixties.
Anyway, I replaced the 20% and 10% resistors with modern 5% film 
resistors and the old paper, mica and electrolytic  caps with new ones.
There were wiring errors in the original kit, and the 10M end of the 
final tank coil was melted (h-m-m-m? - a little out-of band operation, 
perhaps?).

The original DX-40 power transformer always ran hot, so I replaced the 
5U4 rectifier with a pair of microwave oven diodes and added a small 
filament transformer
to take some additional load off the existing transformer.  I never 
cared for having to manually switch the transmitter with the function 
switch,
so I added a PTT circuit.  I replaced the uni-color gray wire with color 
coded hookup wire, added a 3-wire power cord and fuse, and added the 
improvements
which came out in the "second generation" of the DX-40 in 1960.

Is it original?  Not hardly.  Did I butcher the front panel?  Nope. 
You'd never know anything was different unless you took it out of the 
cabinet.

The transmitter runs about 650 volts key-down, rather than 580. Power in 
CW mode is close to 100 watts input, and the interior of the cabinet is 
quite a bit
cooler, now that the 5U4 is gone.

I spent a lot of hours and probably $40 in new parts rebuilding the old 
girl.  After all that, I gave it away!
I took it to my buddy at my local electronics emporium and told him to 
find a home for it.
I have too much ham gear and test equipment as it is.  For me, the fun 
is in the challenge of building and/or repairing gear. Operating is sort 
of in second place.

Am I crazy?  Maybe just a little.  Do I care?  Nope.  I'm having fun.

Build on ...
Mike, WB0LDJ
mharmon at att dot net