I have done the same. It's easy!
First, you have to find a way to hold the can that doesn't pull all the
heat away from the joint. For long cans, you simply clamp the far end
in a vise. For smaller cans, you might have to find another way.
The next step is to attach a handle to the removable lid that will allow
you to pull the lid in an even pressured way.... without worrying about
burning yourself. Pliers can sometimes work, but it is much a much
harder way than simply bolting a strap of steel to the mounting screws.
Then the final step is to use a very hot propane torch, and quickly
heat the can's overlapping joint.
-Chuck Harris
[email protected] wrote:
I have opened quite a few soldered cans using a torch. Max heat for a very
short time did the trick. Any exposed connectors have to be protected. I
use Alum. foil. I have never had any sign of heat on the internal guts.
Bert Kehren Miami
In a message dated 12/5/2009 6:06:56 A.M. Eastern Standard Time,
[email protected] writes:
I had a Knights 10 MHz OCXO that I really liked for my ham stuff,
partially because it was clean and stable, partially because it worked
on 12 V making it great for mobile radio use.
Quite a few years back I messed up and hooked up the battery supply
backwards which killed it. I liked it enough that I opened it up,
replaced a bunch of semiconductors and fixed it. The circuits had
surface mount parts, so I guess it was late 80's or early 90's vintage.
It was a standard large metal can format, about 2 x 2 x 4 inches,
soldered together on the connector end.
Trying to break the solder seal would have been a lot of work. I'm sure
the solder flowed at least 1/8 inch down into the groove between the end
piece and the can. I have a milling machine and I used it to cut a slot
around the outside of the can. The deepest edge location of this cut was
about 0.225 inch down from the end edge of the can. I can't remember
exactly how I decided where to make this cut, I probably made a test cut
in one spot. What I did was cut beyond the solder joint and just deep
enough to go through the outside can, but there was still overlap
between the inner end piece and the can so it was not too difficult to
reassemble after fixing the electronics. I think I tack soldered the
pieces back together and then sealed it with silicon. Finally I wrapped
the outside with foil tape to electrically seal the slot.
If I didn't have the milling machine and slotting saw, I think I would
try my method with a dremel tool by hand before I would try to unsolder,
either mechanically or with heat.
For perspective, I had earlier tried to unsolder a smaller tcxo can. I
used a propane torch with a gentile flame. By the time I got the solder
melted and managed to separate the two halves, I had also desoldered a
number of random devices from the internal circuit board. Unsoldering a
can without overheating the contents is not easy.
So, one more approach for your project.
Joseph Gray wrote:
That's a good idea. I just spent the better part of the past hour
trying it. So far, I have made a nice pile of solder shavings and have
cramped my hand. I haven't succeeded in opening the OCXO, however. The
base fits very snug into the can, so there isn't much more I can dig
out. I'll make another attempt tomorrow, after my hand recovers.
Joe
On Fri, Dec 4, 2009 at 8:46 PM, Ed Palmer <[email protected]> wrote:
I recently had good luck opening up a soldered oscillator with a utility
knife. Rather than use the sharp edge, I used the back edge of the
blade.
That way, instead of trying to push the solder aside, the blade
actually
digs it out of the crack - sort of the way a cutter works in a metal
lathe.
Of course, great care is required to ensure that you don't amputate
something!
Ed
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