On Tue, January 30, 2018 11:33 am, Richard Solomon wrote:

Others have noted that the PCB appears to support multiple different
footprint oscillators or input of an external oscillator.

If the output buffer is not operating properly, then there is a high
likelihood the broken output buffer will just drag down the output of the
OCXO, which will prevent the entire device from operating. Even with the
buffer disconnected you risk disrupting the operation of the GPS receiver
when you connect and disconnect loads to the BNC connector (if the GPS
receiver even keeps operating properly with a 50 Ohm load directly on the
oscillator output).

What are the markings of the devices close to the BNC connector?  Don't
forget to check the bottom of the PCB, there are a few devices there as
well on some models, but I don't know if the layout is the same on all
revisions.

--
Chris Caudle

Just a guess based on some previous comments from Bob, you are probably
looking for a logic gate, probably with an LC filter on the output.  Could
also be some kind of MMIC device, but gate with a filter seems like a good
possibility.
Probably SOIC device, shouldn't be too hard to replace.

--
Chris Caudle

At least one model used a comparatively noisy wideband unity gain analog buffer IC.
Without the buffer the OCXO PN was is lower.

Bruce