Hi …. but … you might *build* one of those oscillators.
The Dewar flask OCXO thing died out many decades ago. The main reason was size. A secondary reason was the fragile nature of a Dewar (they don’t take well to being dropped … I have empirical evidence). Neither one of these issues is particularly significant for a Time Nut basement project. Since they tend to be a bit on the big side, super dense PCB’s are not a major advantage building them. The same auction sites that will sell you questionable OCXO’s will sell you nice working Dewars as components for your build. Bob > On Nov 23, 2016, at 8:33 AM, paul swed <[email protected]> wrote: > > Chris enjoying the pictures. Most likely I will never run into one of these > oscillators. But it is nice to know that you have gone "where no man has > gone before". Star Trek? Not sure. > Regards > Paul > WB8TSL > > On Wed, Nov 23, 2016 at 1:45 AM, Christopher Hoover <[email protected]> > wrote: > >> A Wiha nutdriver set later and I'm in: >> >> https://goo.gl/photos/SDHtvgFmftQq6vYJA >> >> See the last two pictures. >> >> I will disassemble the board stack and work out some schematics next. >> >> Thanks everyone. >> -ch >> 73 de AI6KG >> >> On Nov 20, 2016 5:19 AM, "J. L. Trantham" <[email protected]> wrote: >> >> Christopher, >> >> Enjoyed the pictures. >> >> You might want to look at these items on theBay. >> >> 381408412092 >> >> 311736541103 >> >> I've had the same issue and broke down and bought a set of these small nut >> drivers. >> >> Good luck. >> >> Joe >> >> -----Original Message----- >> From: time-nuts [mailto:[email protected]] On Behalf Of >> Christopher Hoover >> Sent: Saturday, November 19, 2016 11:45 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Inside of FT1200-100 >> >> tl;dr: I've made some progress and have the1200 oscillator core out of the >> dewar: >> >> https://goo.gl/photos/SDHtvgFmftQq6vYJA >> >> >> >> I got some 5 thou brass stock and worked it between the rubber sheet and >> the dewar. >> >> That seemed to help but it was insufficient free things up -- I busted off >> the unused solder lug trying to pull the core out with it. >> >> Having not a lot to lose, I took a chance that the screws going into the >> TO-23 went into threaded holes (rather than being clearance holes with nuts >> inside). This was indeed the case. >> >> With two 6-32 threaded rods into the TO-23 threaded holes and and an >> appropriately machined piece of mild steel bar stock suspended across the >> case <https://goo.gl/photos/1pfiN2GX3WxYCSbg8>, I was able to easily get >> the oscillator core out of the dewar by evenly tightening the the nuts on >> the bar. Really easily -- I might have been able to pull it out by just >> pulling on the bar stock. I don't know if the shim stock shenanigans were >> even needed. >> >> Despite running out the three sloted screws on the "top" around the >> circumference, I'm not into the inside yet. I don't have the right >> thin-walled socket to remove the nuts at the opposite end. >> >> I found an epoxy covered hole on the top. It is/was under the green blob >> midway between 1 and 2 o'clock in this picture here < >> https://goo.gl/photos/ >> iHbSbqwBiKD7NRfJ6>.. There was something blue and >> at this point crumbly underneath it. Not sure yet what, if anything, is >> beyond all of that. I'm hoping for a trimmer cap. :-) >> >> -- Christopher. >> 73 de AI6KG >> >> >> >> >> On Mon, Sep 26, 2016 at 9:24 PM, Chuck Harris <[email protected]> wrote: >> >>> Back when I was going to work on mine, I was thinking of prying the >>> rubber away from the aluminum oven with something like a feeler gauge, >>> but also using some naptha (lighter fluid) to help release any >>> adhesive... I didn't get around to doing it, but that was the way I >>> was going to progress. >>> >>> -Chuck Harris >>> >>> Ed Palmer wrote: >>>> >>>> >>>> On 2016-09-26 10:00 AM, Christopher Hoover <[email protected]> wrote: >>>>>>> >>>>>>> You might be able to slide something like a feeler guage down >>>>>>> between >>> the >>>>>>> oven and the rubber blanket to break the oscillator free. The >>>>>>> oven >>> on mine >>>>>>> is a plain metal cylinder. This way, the rubber sheet should >>>>>>> protect >>> the >>>>>>> Dewar from your feeler guage. On mine, the mounting bolts for >>>>>>> the >>> 2N3792 >>>>>>> transistor both have ground lugs. I think I see them on yours. >>>>>>> You >>> could >>>>>>> hook something through the ground lugs and use that to pull the >>> oscillator >>>>>>> out of the rubber sheet and then remove the sheet later. >>>>>>> >>>>> Thanks Ed, >>>>> >>>>> I think the rubber sheet on mine is against metal. I haven't yet >>>>> seen >>> the >>>>> glass dewar. >>>>> >>>>> The adhesion is huge. >>>>> >>>>> Do you know if the holes opposite the 2N3792 are threaded? If they >>> are, I >>>>> might try running the screws out and using those holes with longer >>> screws >>>>> as my pull points. I can't pull on the lugs hard enough -- I've >>> tried. >>>>> >>>>> -christopher. >>>>> 73 de AI6KG >>>> >>>> Yes, you have seen the Dewar. The silvery ring that's outside the >>> rubber is the top >>>> of the Dewar. What you have to do is unstick and unfold the rubber >>> starting from the >>>> open area in the center. Work your way outward. The rubber is only >>>> 2 >>> or 3 mm >>>> thick. Once you completely clear the rubber out of the way, you'll >>>> see >>> the edge of >>>> the oven. The TO-3 transistor is mounted on top of the oven assembly. >>> Once you can >>>> see the edge, you have to slide something like a long feeler gauge >>>> down >>> along the >>>> edge of the oven to break it free from the rubber. Work your way >>>> all >>> around the >>>> oven. It's about 85 mm long. It'll still be stuck on the bottom, >>>> but >>> you might be >>>> able to pull it free. >>>> >>>> When I took mine apart, I ended up tearing off all the rubber at the >>>> top >>> and then >>>> cutting out that ring of hard foam to get at the Dewar so I could >>>> smash >>> it more. I'm >>>> guessing you'd rather not do that! :) But sacrificing the rubber on >>>> the >>> top might be >>>> okay, if you have to. >>>> >>>> Sorry, but I don't know if the mounting holes for the transistor are >>> threaded or >>>> not. In any case, since the oven and Dewar are bonded to the >>>> rubber, >>> you're pulling >>>> on the Dewar when you pull on the oven. Not a good plan until you >>>> break >>> the oven >>>> free from the rubber. Those Dewars are built in a rather fragile >>> manner. Your >>>> typical home Thermos is much more robust. >>>> >>>> Ed >>>> >>>> _______________________________________________ >>>> 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. >> >> _______________________________________________ >> 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. _______________________________________________ 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.
