So much information from so many that have obviously run into the smell of a burnt part. I do the cut the part to pieces and unsolder each leg. Also the 2 iron approach. The absolute goal, do not damage the board. I have a hot air station also and much like the comments made not impressed. I did grab a scrap board to play with as I was learning. Since your cap looks like it already split in half 50% of the jobs done. As everyone focuses on the soldering part. The damaged board is equally critical. The stuff in tantalums is nasty. I clean the whole area with alcohol. And at times actually carve out some of the carbon if I can measure some level of resistance from each trace to the center point. Your problem looks simple enough Tom. Just remember this. I hate caps. But have received some of my best equipment because they fail for $/pound. Kind of a love hate thing. Regards Paul WB8TSL
On Sat, Nov 5, 2016 at 4:37 PM, Tom Miller <[email protected]> wrote: > 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" <[email protected]> > To: "Tom Van Baak" <[email protected]>; "Discussion of precise time and > frequency measurement" <[email protected]> > 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 <[email protected]> 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>_______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to https://www.febo.com/cgi-bin/m >>> ailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
