Hi I suspect that the unit puts out an ok 10 MHz signal. That would suggest that the +12 and likely the +5 supplies are ok. If the monitor software can talk to it, that's another indication that the +/-12 and +5 are fairly close to working.
I think that a problem with the GPS front end / antenna connection is the most likely issue. Here's another one to consider though: How far off *is* the 10 MHz output? If the OCXO has gone way off frequency, the GPS may not be able to lock. It should be pretty simple to check with a counter and the second TBolt. Bob On Jun 10, 2010, at 8:22 PM, Didier Juges wrote: > The TB has an error flag if there is no antenna connected (open) or if it is > shorted. The tboltmon PC software reports these flags, and so does my GPSMon > firmware in the fluke.l monitor. > > It is possible but unlikely that there would be something wrong with the bias > circuit that would not be reported by the TB. > > Didier > > > ------------------------ Sent from my BlackBerry Wireless thingy while I do > other things... > > -----Original Message----- > From: Arthur Dent <[email protected]> > Date: Thu, 10 Jun 2010 15:49:00 > To: <[email protected]> > Subject: [time-nuts] Thunderbolt not seeing satellites > > > It may or may not tell you what's wrong but a quick check of the > Thunderbolt would be to put a tee in series with the antenna and > see if the unit is supplying +5 volts under load to the antenna.You > have verified that the antenna works with a second unit so you can > rule that out. Where you are getting some data from Lady Heather > showing it picks up at least 1 satellite I suspect the +5 Vdc power > supply that supplies the logic is functioning properly or you'd probably > see no data. The +12 Vdc mainly supplies the oscillator so if that's > working properly, the +12 is probably ok, It may well be a component > in the receiver section on the Thunderbolt board. > > The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier > ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM500002.pdf ) > located on the top side of the board directly behind the antenna connector. > The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS > connector and they apparently supply the +5 to power the antenna. Those > two areas would be likely suspects. > > > > _______________________________________________ > 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.
