[time-nuts] Inside of FT1200-100
ch at murgatroid.com
Sun Nov 20 00:44:50 EST 2016
tl;dr: I've made some progress and have the1200 oscillator core out of the
I got some 5 thou brass stock and worked it between the rubber sheet and
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
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. :-)
73 de AI6KG
On Mon, Sep 26, 2016 at 9:24 PM, Chuck Harris <cfharris at 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 at murgatroid.com> wrote:
> >>> >
> >>> >You might be able to slide something like a feeler guage down between
> >>> >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
> >>> >Dewar from your feeler guage. On mine, the mounting bolts for the
> >>> >transistor both have ground lugs. I think I see them on yours. You
> >>> >hook something through the ground lugs and use that to pull the
> >>> >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
> >> 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
> >> as my pull points. I can't pull on the lugs hard enough -- I've
> >> -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 at febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > and follow the instructions there.
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> and follow the instructions there.
More information about the time-nuts