4060 CMOS 14 bit binary counter IC

 PRO2004.1

   A pushbutton switch, attached to a 4060 CMOS 14 bit binary counter IC,

selects one of the 16 groups.  The 4 counter output leads are used to select

the high order 4 bits of the HM62256.  The new group select pushbutton switch

is mounted on the front panel, in place of the headphone jack.


   How can you tell which group you are in?  A specially programmed  EPROM

(type 2716, 2532, or 2732) is addressed by the ouput of the counter.  The

EPROM output is connected to a 7 segment LED readout, mounted in place of the

Sound Squelch pushbutton.  The readout indicates groups 0, 1, 2, 3, 4, 5, 6,

7, 8, 9, A, B, C, D, E, and F.


   [Note: If I were to expand the memory in my PRO-2004,  I would use just the

new HM62256 memory IC and a BCD switch instead of the pushbutton.  This would

eliminate two of the three ICs, and the 7 segment readout.  Sorry, I cannot

provide further information, nor a reference, as the sheets sent to me

contained no name or address. - Bob

   Parnass] Bob Parnass AJ9S

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