---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/28/11: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:36 AM - Tiny solder tab (Stuart Hutchison) 2. 08:10 AM - Re: Tiny solder tab (Robert L. Nuckolls, III) 3. 08:46 AM - Re: Tiny solder tab (Christopher SeeStone) ________________________________ Message 1 _____________________________________ Time: 07:36:47 AM PST US From: "Stuart Hutchison" Subject: AeroElectric-List: Tiny solder tab G'day Bob, I have a tiny soldering job to do because the return wire shown in the photo has separated from the LED solder tab. The LED OEM (Luminus) data sheet says that the used and spare cathode (just visible at the top of the LED base) are interconnected, but there would be more strain on the main wire to reach the spare solder tab. Perhaps a small jumper between the first and second cathode (and same for the anodes) would be smart too, but I need to re-attach the wire without damaging the LED. I have some ideas about how to provide strain relief and protection for the wires Bob, but what do you think is the best way to prepare and re-solder to this tiny solder tab, which is only about 1/16 x 1/8" in size? For reference, the screws are M3. Cheers, Stu ________________________________ Message 2 _____________________________________ Time: 08:10:52 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Tiny solder tab At 09:32 AM 6/28/2011, you wrote: >G'day Bob, > >I have a tiny soldering job to do because the return wire shown in >the photo has separated from the LED solder tab. The LED OEM >(Luminus) data sheet says that the used and spare cathode (just >visible at the top of the LED base) are interconnected, but there >would be more strain on the main wire to reach the spare solder >tab. Perhaps a small jumper between the first and second cathode >(and same for the anodes) would be smart too, but I need to >re-attach the wire without damaging the LED. I have some ideas >about how to provide strain relief and protection for the wires Bob, >but what do you think is the best way to prepare and re-solder to >this tiny solder tab, which is only about 1/16 x 1/8" in size? For >reference, the screws are M3. What AWG are these wires? How much current does the LED draw? The first idea that comes to mind is replacing the wires with smaller gage still sufficient to the current. I'd bet you can go down to 24 or perhaps 26AWG. Remove all the existing 'fat' wires and bring smaller leads to the outside of the enclosure. Use some form of adhesive/sealant to secure the wires as they pass through the housing. Once in the more robust, outside world, figure out some form of connector . . . or perhaps splice to more robust leads and secure the joint mechanically under a band-clamp. You need a soldering iron with a small tip and some 63/37 solder. I'd clean off the pads with a piece of solder-wick, re-tin the pads with small dots of solder. Tin the ends of wires to be attached. Then 'tack' the wires onto the pads. Bob . . . ________________________________ Message 3 _____________________________________ Time: 08:46:37 AM PST US Subject: Re: AeroElectric-List: Tiny solder tab From: Christopher SeeStone Stu, If that's a MCPCB (metal core printed circuit bard, typically aluminum) you will need to preheat the board (and LED) on a hot plate to properly solder to the pad. Without heating the board you will never get the solder to flo w on the pad. At work we build hundreds of these type of LED assemblies. We set our hotplate to 150=B0 C and use 63/37 Pb/Sn solder. Place the MCPCB o n the hotplate. Place a small piece of solder on the pad. Bring the tinned wire and soldering iron tip in contact with the pad. The solder should flo w freely. Remove the solder iron and the solder should re-solidify on the pa d with the wire embedded. Remove the assembly from the hotplate. Chris Stone RV-8 OR On Tue, Jun 28, 2011 at 7:32 AM, Stuart Hutchison < stuart@stuarthutchison.com.au> wrote: > ** > G'day Bob, > > I have a tiny soldering job to do because the return wire shown in the > photo has separated from the LED solder tab. The LED OEM (Luminus) data > sheet says that the used and spare cathode (just visible at the top of th e > LED base) are interconnected, but there would be more strain on the > main wire to reach the spare solder tab. Perhaps a small jumper between the > first and second cathode (and same for the anodes) would be smart too, bu t I > need to re-attach the wire without damaging the LED. I have some ideas > about how to provide strain relief and protection for the wires Bob, but > what do you think is the best way to prepare and re-solder to this tiny > solder tab, which is only about 1/16 x 1/8" in size? For reference, the > screws are M3. > > Cheers, Stu > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.