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Unofficial Ten-Tec web pagehttp://mywebpages.comcast.net/w8kc/tentec.html
The Century 21 (C-21) was Ten*Tec's answer to the call for a low priced, entry level, novice rig in the mid 1970's.
Very popular, and the C-21 helped many Novices upgrade to General class quickly. This is partly in thanks to the attention paid to its superb CW operation including 3 filter bandwidths. Direct conversion receiver, but without the broadcast band blow-by of the Power Mite.
The C21 was also available as a "digital" version with large LEDs replacing the dial. 35 watts RF output, 80-10 meters. 120VAC powered.
BE PREPARED to rebuild the PTO of this transceiver (known, well documented problem).
No Big Deal @ $25 and a couple hours of your time (or a technician's - IF you can not handle small parts).
Here is Monty, N5ESE excellent website on the C-21 PTO REBUILDhttp://www.io.com/%7En5fc/c21_pto.htm