Hi > On Nov 14, 2015, at 8:01 AM, Pete Stephenson <[email protected]> wrote: > > On Sat, Nov 14, 2015 at 12:00 AM, Bob Camp <[email protected]> wrote: >> Hi >> >> First thing to check is that it really *is* at limit. There apparently are a >> few odd things >> that can trigger the alarm. > > What sort of odd things might cause that?
Since we do not have an exact firmware dump of any of the TBolt firmware (let alone a dump of each version) it’s only a guess as to what can trigger the alarm. What I have seen are OCXO’s that trigger it without being at either end of the tune range. What I would guess is that there is some sort of aging estimation going on. > > It was weird: yesterday LH highlighted the DAC value which was around > 0.38V (I didn't write down the number, alas) and the "osc age alarm", > both of which were red. Which is the sort of thing I have seen. > > I did a factory reset for good measure and things cleared up. The DAC > value is now around 0.42V and the alarms are off and everything is > green. The OSC plot in LH tracks the DAC value, so it appears that the > Thunderbolt is able to control the oscillator reasonably well. > > What's the max range that the DAC can produce? +/- a volt? Two? The DAC range is +/- 5V. The OCXO’s apparently start out from the factory set to center at 0V. If that’s true, your 0.4V OCXO has aged less than 10% of the range in how ever many years since it left the factory. > >> The OCXO’s out of the TBolt are sold on the auction sites from time to time. >> They >> seem to go for < $40 delivered. The footprint on the OCXO is pretty >> standard. You >> can tune the parameters on the TBolt. There are a lot of other choices. >> About the only >> real limit is the 10 MHz frequency. > > Cool. I see a bunch of Trimble and non-Trimble oscillators for sale on > eBay but would hate to get the wrong one. Does it need to be the exact > same model number, or are they usually all compatible (assuming that > they are 10MHz and use the same voltage for the oven and other > electronics? I would go for a proper TBolt part. I’d get one with the most recent date code you can find. Newer is always better :) To get the right sort, I’d take Tom up on his offer. It sounds like the best deal I’ve heard. Bob > > Cheers! > -Pete > > -- > Pete Stephenson > _______________________________________________ > 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.
