On 2016-09-26 10:00 AM, Christopher Hoover <ch@murgatroid.com> 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

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 <ch@murgatroid.com> 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 -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

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 <cfharris@erols.com> 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 <ch@murgatroid.com> 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 -- 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. >

Christopher wrote: > 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. It looks like a standard 5/32" nut driver will work fine. <http://www.homedepot.com/p/203310440> Best regards, Charles

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:time-nuts-bounces@febo.com] 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 <cfharris@erols.com> 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 <ch@murgatroid.com> 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 -- 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. > _______________________________________________ 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.