What were the differences between the DX-100 and the DX-100B?

Was there a DX-100A?

Rick (W-A-one-R-K-T) wrote:
What were the differences between the DX-100 and the DX-100B?

Was there a DX-100A?

No, they went straight from the plain to the B model.

Differences:

100 - 4 crystals or VFO, switched from front panel
100B - 1 crystal with switch inside cabinet

100B - chassis punched for connectors for the SB10 SSB adapter

100 - course loading and fine loading control
100B - larger gear driven loading capacitor

100- knobs point with narrow white lines
100B - knobs point with white triangles

100- multi piece cabinet
100B- one piece cabinet with hinged hatch on top
for access to the crystals


This information is paraphrased from Chuck Penson's
book, "Heathkit, A guide to the Amateur Radio Products"

-Chuck

On Jul 30, 9:30 am, Chuck Harris wrote:
Rick (W-A-one-R-K-T) wrote:
What were the differences between the DX-100 and the DX-100B?

Was there a DX-100A?


Chuck and Jim's answers seem complete to me. The Heath retrofit kit
was the "MK-3" to replace the Coarse Loading switch.

FWIW- This subject formed the original discussion that led KM6NK to
start the first "boatanchors" e-mail list 15 years ago, and which
became the inspiration for rec.radio.amateur.boatanchors

73 & Have Fun,
Nick KD4CPL

On Jul 30, 8:35 am, "Rick (W-A-one-R-K-T)"
wrote:

Was there a DX-100A?

Not formally, but you may see informal references to "DX-100A"

What happened was this:

The original DX-100 used a relatively-small air variable loading cap
for fine adjustment, and a bunch of switched fixed caps for coarse.

In practice, this combo turned out to be unreliable in ham use, and in
the DX-100B the combo was replaced by a large air variable loading
cap.

Heath sold a retrofit kit so that DX-100 owners could replace the
small-air variable-cap-and-bunch-of-switched-fixed-caps arrangement
with the DX-100B style setup. Retrofitted DX-100s became known as
DX-100As. I don't know if that's an official Heath name or just
something hams made up. I do know that when Heath came out with the
new model, they called it DX-100B.

At least that's the history I knew.

--

btw, if your DX-100 has only one fuse in the primary side, it needs to
be modified so each power transformer has its own fuse.

73 de Jim, N2EY