Hi How old is the FRK? Does it look like it's been run without a heat sink for very long? They tend to get flaky if run for a while (many months) without heat sinking. There's nothing mysterious about it. The MTBF of the parts gets noticeably worse as the unit heats up.
Bob On Feb 9, 2013, at 1:09 AM, Garren Davis <garren.da...@qlogic.com> wrote: > > Well for some reason the 10 Mhz stopped working on the FRK. Don't know why. > Started up the thunderbolt. It acquired satellites but then the DAC voltage > went to -5 volts. It's been there for an hour. Will this change after the > unit stabilizes? Going to bed. Will check it tomorrow. > > Garren > > > > > On Feb 8, 2013, at 8:25 PM, "Ed Palmer" <ed_pal...@sasktel.net> wrote: > >> Hi Garren, >> >> I suggest that you get the Thunderbolt working first. Without a known 10 >> MHz source to compare to, you're flying blind. Once the Tbolt is running, >> you should be able to check the frequency of the FRK by feeding both into >> your scope. Trigger on the Tbolt and watch what the FRK does. You should >> see the trace scrolling in one direction, then slow down, then stop, then >> scroll the other direction. The 'stop' point is at 10 MHz. The frequency >> sweeps a total of 20-30 Hz so it's easy to see. If you don't see the 'stop' >> point, the FRK isn't getting to 10 MHz. Now use the best frequency counter >> you've got to measure the Tbolt. Regardless of the calibration of your >> counter, the number your counter gives you becomes your 'new' 10 MHz. Now >> measure the FRK to see if it's running fast or slow. >> >> You should check the temperature of the lamp. It's easy to get at by >> removing the cover in the center of the heat sink. Probably best to remove >> the cover and then power down before you go poking around inside! The >> temperature of the cavity is also important, but getting to it is more of a >> hassle - don't go there if you don't have to. >> >> Of course, check for the normal things like internal power supply voltages, >> ripple, current drain (both initial and steady-state), etc. >> >> Regarding your second message, yes, the adjustment under the heat sink near >> the edge is the C-field. That won't help you at this point. The adjustment >> in the center of one side is the VCO. You could try adjusting it, but like >> I said, you're flying blind at this point. You won't know if you're >> adjusting closer to 10 MHz or further away. >> >> Good luck, >> >> Ed >> >> >> On 2/8/2013 6:12 PM, Garren Davis wrote: >>> Been lurking on the list for a while and finally started playing with a >>> FRK-L rubidium frequency standard. I've had this thing for a while and >>> decided to power it up and see what it would do. I do not get a lock. What >>> I see is the lamp voltage at 8.54 volts which I think is good but the xtal >>> control voltage swings from 2 volts to 15 volts and back to 2 volts and >>> keeps cycling like that. I don't have a good frequency counter but I have a >>> 3 Ghz 40 G/sample scope and it shows that the 10 MHz signal is there. I >>> just don't know how accurate it is. Has anyone seen a problem like this? >>> Can anyone point me to a place to start debugging this? I have the >>> schematics and test tools. I am a test engineer so I'm not afraid to poke >>> around in the guts of this thing. Hopefully I can get this thing running. I >>> also have a thunderbolt that I'll get running this weekend. I don't know >>> how deep I'll get into this time-nuts thing but I have this nice scope and >>> a Wavecrest sitting in my garage an > d >> I'd lik >> e to put them to use. Any help would be appreciated. >>> >>> Garren >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > ________________________________ > > This message and any attached documents contain information from QLogic > Corporation or its wholly-owned subsidiaries that may be confidential. If you > are not the intended recipient, you may not read, copy, distribute, or use > this information. If you have received this transmission in error, please > notify the sender immediately by reply e-mail and then delete this message. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
