January 16, 1987

HD-1530                                         Bulletin No:

Touch-Tone(R) Decoder                           HD-1530-1



        Won't Indicate Valid A, B, C and D Tones Except At Very Low

                                  Audio Input Levels



In the input circuitry of the DTMF receiver at U103, change:



        R107 from a 100 kilohm resistor to a 47 kilohm resistor [PN

6-473-12].



Install this change only when needed.

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Thats everything I hold up to 1989 that covers the HD-1530.  Enjoy!

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73 de Joe  W7LPF/4  [NNN0KUU]

QWCA - SOWP - NCVA - FISTS - RCC

Gordonsville, Va 22942 [Orange Co]