Hi If I remember it’s a half turn trimmer. The “right” direction will depend on where they left it …
If it’s multi turn then the answer is counterclockwise. Best to simply watch the result on a counter. Bob On Dec 14, 2013, at 4:09 PM, Jamieson (Jim) Rowe <[email protected]> wrote: > Hi Bob, > > Thanks for that tip. I have tweaked C217 a bit already, but I'll try again in > the hope that it'll finally do the trick. By the way, which is the correct > direction to push the frequency up a tad -- clockwise or anticlockwise? I > think I tried antclockwise the first time... > > All the best for the festive season. > Jim Rowe > > > -----Original Message----- From: Bob Camp > Sent: Saturday, December 14, 2013 5:14 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? > > Hi > > One thing it could be is the VCXO not quite making it above 10MHz for long > enough to lock. I’d tweak the cap to move it up and see what happens. > > Bob > > On Dec 13, 2013, at 8:49 AM, [email protected] wrote: > >> Jim >> unlike older Rb's there is very little analog in the unit. It is sweeping >> trough its lock range so maybe you may find something around the lamp. The >> lamp should not be the problem because the 5680 has not been around and >> been operating for extensive time before pulled. >> How ever I like to caution time nuts and be careful who they buy from, I >> did have a bad experience with one vendor and I did post it previously. >> False claim of new and when returned after return authorization refused >> refund >> since I refused to give a 5 star rating. I forwarded the emails to ebay and >> they did nothing. So any time nut that buys from ggg* fitting deserves >> what he is getting. We have other sources out there that time nuts have good >> experiences with and with the price increasing by a factor of 4 one should >> be careful. Personally I do not think they are worse the price >> Bert Kehren Miami >> >> >> In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, >> [email protected] writes: >> >> Hi, >> >> I’m an elderly time-nut newby, and I’ve already struck trouble with a >> used FE-5680 Rb-vapour reference >> I bought via eBay. It runs (from +16V and +5V), and the current drain >> starts at 1.75A and then drops over >> 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it >> powered up for a few hours (with a fan >> to keep it from getting too hot). >> >> The output frequency just keeps switching up and down between about >> 9999850Hz and 10000080Hz, with a bit of ‘lingering’ >> near each end. And of course the ‘lock’ output at pin 3 stays stubbornly >> at about 4.35V. >> >> To my newby brain, this sounds like the problem is either in the Rb lamp >> (too dark, perhaps), or >> else in the photodetector and buffer, etc, forming the ‘dip detector’ >> part of the feedback loop. >> >> Could one of you much-more-experienced time-nutters tell me if my >> diagnosis sounds right? >> >> Also, I’ve found a schematic for the digital sections of the FE-5680A in >> your archives, kindly drawn up >> by one of your very experienced members, but has anyone done a similar >> schematic for the ‘analog’ >> sections? I suspect I’m going to have to work out for myself where to >> test for a fault in these >> sections. There’s also a bit of a mystery (in my mind, at least) regarding >> that little 2-pin SIL header >> just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? >> >> All the best in anticipation, folks. >> >> Jim Rowe >> _______________________________________________ >> 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. > > _______________________________________________ > 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. _______________________________________________ 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.
