If Hallicrafters had not run in to contractual problems with State and Federal government production contracts I believe the 400 series would have taken over the medium priced transceiver market. The SR-400 Cyclone proved the design concept. The Cyclone II and Cyclone III refined it. The 95% failure rate of the FPM-300 also struck at about the time of the release of the Cyclone II. All this and more added up to the demise of Hallicrafters. The Cyclone II is arguably the better of the three. To this day any of the three properly refurbished SR-400’s will be a proud addition to any vintage shack.
Need a fresh look at troubled radio? Contact me, perhaps we can work it out together. Use the CONTACT page on this site.

SR-400 RESTORE AND REPAIR MANUAL
LOW POWER IN CW/TUNE FUNCTIONS
CYCLONE TO CYCLONE II CONVERSION
CYCLONE & CYCLONE II PA UPGRADE TO 6KD6