[time-nuts] I love the smell of tantalum in the morning

Tom Miller tmiller11147 at verizon.net
Sat Nov 5 20:37:59 UTC 2016


I usually nibble away at the center of the part until it is two separate 
pieces. Then unsolder each piece. Clean the pads off with wick then install 
the new part.

Use a good sharp pair of flush cut side cutters.

Tom


----- Original Message ----- 
From: "Bob Camp" <kb8tq at n1k.org>
To: "Tom Van Baak" <tvb at leapsecond.com>; "Discussion of precise time and 
frequency measurement" <time-nuts at febo.com>
Sent: Saturday, November 05, 2016 4:24 PM
Subject: Re: [time-nuts] I love the smell of tantalum in the morning


> Hi
>
> A *lot* depends on how many planes there are in that board. The weight of 
> he copper
> also maters a bit. If there is enough thermal mass, you will need a 
> pre-heat process.
> There are lots of ways to do it ranging from the kitchen oven to various 
> “frame and
> lightbulb” setups and on into ever more complex heating approaches.
>
> If the hot tweezers / soldering iron / hot air tool does not reflow the 
> solder quickly (10 seconds
> or less) stop. Get a pre-heat setup and try again. With proper heat you 
> should have the part
> off in under 4 seconds. People don’t tend to use stopwatches when 
> soldering. 4 seconds is quite
> a while on a joint. Ten seconds is pretty much forever ….
>
> Bob
>
>> On Nov 5, 2016, at 3:12 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
>>
>> See C13 in the attached photo. I need to replace some blown caps on a few 
>> boards [1]. In one instance the cap got so hot it melted itself off the 
>> board. Quiet convenient, actually -- it acts like its own fuse -- but I 
>> don't think the 5071 designers had that clever feature in mind.
>>
>> Having not done SMT before, how should I do it with minimal risk to the 
>> very precious PCB. Or, what equipment should I use this as a good excuse 
>> to buy?
>>
>> Thanks,
>> /tvb
>>
>> [0] http://www.imdb.com/title/tt0078788/quotes
>> [1] http://leapsecond.com/museum/hp5071a/A1-mother.htm
>> <A1-mother-6.jpg>_______________________________________________
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