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 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
