[time-nuts] Thunderbolt "osc age alarm", where to get replacement oscillator?

Pete Stephenson pete at heypete.com
Sat Nov 14 08:01:30 EST 2015

On Sat, Nov 14, 2015 at 12:00 AM, Bob Camp <kb8tq at n1k.org> 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?

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.

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 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


Pete Stephenson

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