Hi At this point I'd contact the seller. You know that the part has a problem and you have done enough checking to be sure it's nothing trivial (like a loose wire). The worst that can happen is he does not reply, the best is that he sends you another part for free. There are a number of possibilities in-between the two. At this point you have a pretty good case. Once you start twiddling this or that, you are not in as good a position.
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Beale Sent: Wednesday, November 30, 2011 2:18 AM To: [email protected] Subject: [time-nuts] troubleshooting a FE-5680A (got two; only one works) Just yesterday I received two FE-5680A units from China. One of them works and one doesn't achieve lock. Both are labelled with FEI P/N 217400-30352-1. Here's a photo of the one that works, the other looks just the same but different serial number. https://picasaweb.google.com/109928236040342205185/FE5680A#56804736636531401 62 FE-5680A Rb #1: At startup, RF out (pin 7) ramps from 9.999828 to 10.000066 MHz for a few minutes, then locks at 10.000000 MHz and pin 3 drops low. The RF signal is about 2 Vpp. Power draw at startup about 25 W, dropping to 10 W. FE-5680A Rb #2: RF out scans from 9.999799 to 9.999994 MHz repeatedly, and does not achieve lock. Pin 3 remains high. The RF signal is about 1 Vpp (half the level of the working unit). Power draw similar to unit #1. Any suggestions for what might be done to prod the 2nd unit towards working? I see some things which might be trimmer caps on the board, and what might be a round heating element(?) soldered to a crystal can in this photo: https://picasaweb.google.com/lh/photo/0WRM10pGG0Kd89Ji80yoa9MTjNZETYmyPJy0li ipFm0?feat=directlink thanks for any advice! John Beale N8JUF _______________________________________________ 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.
