SB-650/led modification

Mark Graalman WB8JKR wb8jkr at JUNO.COM
Sun May 2 12:17:18 EDT 2004


  I have a question for you digital TTL type guys, I'm an
RF man myself.  ;^)

 Anyway, I'm thinking about converting my SB-650 from a
nixie readout to a seven segment LED display. It looks
to me like "basically" the 7447 BCD/decoder driver for the
LED's is the same thing as the 7441 used to drive the nixies
except for interchanging a few pins.

 Of course the +170 volt supply for the nixies would no longer
be needed, just the 5 volt supply for the LED's, and I think the
stock circuit board can remain, just pull out the 7441's and run the
four lines from each storage register to each 7447 input.

 Any thoughts?

73, Mark  WB8JKR

Support Amateur Radio, have a Ham for dinner
Member ARRL, QCWA, OTC, Society of Cable Telecommunication Engineers
WAS, WAC, WTO, DXCC MIXED, DXCC PHONE, GJDXCC, VUCC 2M, 1st place Ohio
single op 1988 ARRL  Sweepstakes
Novice 3/71, General 8/72, Advanced 8/78, Extra 8/89

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