K7AAE - Bob Swain
Information on CX11 S/N 922740

My CX11 S/N 922740 is now once again among the living. This was radio #15,
the last CX11 produced before the CX-11A was introduced.

I acquired the radio several months ago, but have been busy and just
recently managed to find the time to work on it. The radio had power supply,
counter / display and IF board problems as received.

Trouble shooting was interesting ( this is putting it mildly) since some of
the boards are similar, but different, being early versions and using
individual pins and multi pin Berg connectors instead of the ribbon cables
and mother boards that are found in the CX-11A. Oh, did I mention that there
apparently was never a factory produced manual, and the radios were
supposedly built two or three at a time, with circuit board changes,
connections, wire numbering and wire colors changing from batch to batch!

The radio uses a multiple oscillator board with crystals instead of the
synthesizer in the CX-11A, and the AGC board has a 100 KHz crystal
oscillator (similar to the CX7) instead of the 10 MHz chip oscillator used
in the CX-11A.

I managed to use a lot of tantalum caps, and replaced the 5, 15 and -15 volt
regulators with new production units. I also added a few of the later
production updates and mods to the A3 power supply board while I had it out
for repair. I found it interesting that after all these years, there were
several instances of original parts with one or more leads in the proper
hole, but not soldered to the board. 
 
My thanks to Bill Turini, and others that helped by listening to my rants
and ravings, and by supplying bits and pieces of information on the CX11.

The radio needs to be aligned (my next project), but is fully functional,
sounds good on receive and received good reports when I made a couple of
contacts with it.

The Signal One's are great radios and deserve to be kept working and on the
air.

Bob K7AAE


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Created: October 11, 2011. Last Updated: October 13, 2011
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