I've used an LED direct to the lock output. 330R resistor in series and the other end of the LED to the +5V rail.
Works fine for me, but then, I'm not interested in the 1PPS (actually not even sure my bricks have that feature). Rob Kimberley -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of bob grant Sent: 02 February 2012 20:46 To: [email protected] Subject: [time-nuts] FE5680 missing PPS soln Some info... Its tempting to attach an LED to the /LOCK signal on the DB9. However this signal is very weak and the LED does not seem very bright and PPS signal does not pulse...Hmm Internally the /LOCK pin is connected the 74AC240 buffer, but with an LED helping to keep the signal voltage high (2.3V) a logic low is never asserted. This logic low is needed to enable one half of the 74AC240 buffer (pin 1) that gates the PPS signal. Don't directly drive LEDs from the LOCK signal on the DB9 and, voila, the PPS signal reappears. Bob -- bob grant [email protected] -- http://www.fastmail.fm - Choose from over 50 domains or use your own _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
