[Elecraft] OT - Heath CW Twins

[John H Gibson]

Hello David,

Chuck Penson's excellent book, HEATHKIT: A GUIDE TO THE AMATEUR RADIO 
PRODUCTS, 2nd Ed., lists both the HR-1680 and the HX-1681. According to 
Chuck, the HR-1680 was released in the Fall of 1967, but the HX-1681, which 
initially was advertised as "coming soon," was plagued with problems and not 
released until the summer of 1979. 

Continuing Chuck's comments, early HX-1681s had key-click problems, and 
Heath provided a free modification to owners to remedy this. This modification 
was included in later-production HX-1681s. A modification to solve the key-
click appeared in the March, 1981, QST. Eventually the HX-1681 was pulled 
from production a year earlier than the HR-1680. 

Chuck further says that, the both the HR-1680 and the HX-1681 use plug-in 
circuit cards, and the card-edge connectors are subject to oxidation over time. 
These connector contacts may need periodic cleaning.

Overall, Chuck Penson has kinder things to say about the HR-1680 than he does 
about the HX-1681.

I hope this is helpful

73,
John, no8v