[time-nuts] 5MHz ocxo

Thu Jul 26 17:52:50 UTC 2012

"Everything old is new again."

Now that I think about it, maybe the added solder is helping by doing 
more than just transfer the heat.  As the current, which is at least 100 
amps, spreads from the copper to the solder, the solder will heat up 
which is exactly what we want.

Ed

On 7/26/2012 9:19 AM, Ron Ward wrote:
> Hi ED:
> Good point but I guess that it's all resistance heating and copper is
> about 10 times more conductive than steel and the contact surface area
> is quite small. Anyway, it has worked for me several times in the past.
>
> I did a search at the ARRL website on crystal grinding and found two
> articles that may interest you!
> QST July 1963 page 75 "Removing Hermetically-Sealed Crystals" and
> QST March 1963 pages 30,31 "Grinding Surplus Hermetically sealed
> Crystals".
>
> I didn't know that these articles existed until I did the search. Talk
> about re-inventing the wheel!
>
> Ron
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Ed Palmer
> Sent: Thursday, July 26, 2012 12:43 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 5MHz ocxo
>
> I'm not the original poster with the dead oscillator, but I have done
> this in the past ( and will again in the future, I'm sure).  I'm
> definitely going to try this idea.  I have both models of soldering gun
> as well.  The bigger one is Model D550 and is rated at 200/260 watts.  I
>
> think that's the one to use.  As you say, you want to work fast and the
> larger one will do that.  I'm a little surprised that wrapping the wire
> around a metal case and using solder to improve the heat transfer
> doesn't more or less short out the loop and reduce the heat generated on
>
> the side of the loop opposite to the connection points.
>
> Ed
>
>
> On 7/25/2012 11:55 PM, Ron Ward wrote:
>> Hi:
>> I have two. Both are made by Weller. The first one is rated for
> 100/140
>> Watts and works well for disassembling soldered HC-6U crystals without
>> damaging them. The second one is at least 250 watts maybe as high as
> 300
>> Watts. It is old and the label is missing. It has two lamps for
>> illumination. I feel that if you make the wire tight aginst the solder
>> area of the case that the 100/140 watt gun would work okay. Be sure to
>> tin all of the contact area of the wire that is wrapped around the
>> case's soldered junction. The non-contact area of the wire may be left
>> to oxidize and will act like an insulator making the tined area
> hotter.
>> Fresh rosin core solder is easier to work with. Solder braid is also
>> very helpful to clean up the groove after the top of the case comes
> off.
>> Be sure to ware safety glasses or goggles. Not much solder is released
>> but I wouldn't take any chances!
>> Also you might try both #12 and #14 as I don't know the current rating
>> of your soldering gun. The resistance of going to #12 wire is
>> compensated by the longer length for larger cases. I have never tried
>> Chip Quick but it could also be helpful. You could have a friend
> preheat
>> the case with a large soldering iron if extra heat is required. I like
>> the soldering gun because it makes for a nice clean job when finished.
>> You will want to work fast so as not to heat damage the oscillator's
>> components.
>> Ron
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
> On
>> Behalf Of Ed Palmer
>> Sent: Wednesday, July 25, 2012 8:28 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] 5MHz ocxo
>>
>> I haven't heard of that trick before, but it sounds interesting.
> What's
>> the wattage of your soldering gun?
>>
>> Ed
>>
>>
>> On 7/25/2012 6:41 PM, Ron Ward wrote:
>>> Hi:
>>> If you want to de-solder the case, I have had success taking some #12
> or #14 bare copper wire ( standard solid conductor house-wiring stripped
> of the PVC insulation ) and wrapping it tightly around the base just
> above the soldered junction. The wire is installed in my soldering gun
> just like a new soldering gun tip. Add just a little solder to help in
> heat transfer. Be careful as it will get really hot. I hold the top with
> a weird set of very long needle nose pliers. They are small enough that
> they don't act like much of a heatsink. You could fabricate one out of
> wood. They would be disposable.
>>> I hope this helps,
>>> Ron
>>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>>> On Behalf Of Paul Flinders
>>> Sent: Wednesday, July 25, 2012 2:59 PM
>>> To: Tom Miller; Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] 5MHz ocxo
>>>
>>> On 25/07/12 22:27, Tom Miller wrote:
>>>> Can you post up a few pictures of the oscillator?
>>>>
>>>> There have been people that have opened these up and repaired them.
> If you feel not up to it, why not see if someone on this group can help.
>>>> Repairing it will eliminate a lot of searching.
>>> Pictures at
>>>
>>> http://www.wild-pc.co.uk/images/P1000981.jpg
>>> http://www.wild-pc.co.uk/images/P1000982.jpg
>>> http://www.wild-pc.co.uk/images/P1000983.jpg
>>>
>>> Apologies for slightly poor quality.
>>>
>>> It's fully soldered at the base - possibly wasn't done in one go but
> I
>>> suspect would all have to be heated to get it apart - I have an SMD
>>> style hot air gun but it couldn't tackle that job.
>>>
>>> If anyone is able to repair it I'd certainly be interested.
>>>
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