SOT23 desoldering tip - Page 1
Forum section: electronics / general

author: Geoff
author_rank: Contributor
timestamp: November 27, 2021, 06:27:57 pm
content: Does anyone use a "Chip Components" de-soldering tip?Is there a "Chip Component" de-soldering tip for SOT23eg:https://www.jbctools.com/cartridges-category-4-design-Chip-menu-4.html

author: ataradov
author_rank: Super Contributor
timestamp: November 27, 2021, 06:43:36 pm
content: Do you need the component to survive? If not - big blob of solder and a regular soldering tip would work. Heat each pin by moving the blob around, eventually they all will heat up enough. And if you do rework more or less often - get a hot air station. No matter the tip - desoldering stuff like this with a soldering iron is a pain.If it is SOT23-3, then you can also lift one pin, then desolder the rest of them. This will mot damage the device if done carefully.Or you can cut the pins if you don't need it to survive at all.

author: jpanhalt
author_rank: Super Contributor
timestamp: November 27, 2021, 06:51:41 pm
content: "Chip-Quik" which is a very low melting solder may help. If you have access to a little "Wood's" meltel or anything similar, that may work too. Otherwise, I would just use my flush cutters to cut 1 or 2 of the legs off and remove in the usual way.

author: wraper
author_rank: Unknown
timestamp: November 27, 2021, 07:10:13 pm
content: Two soldering irons (one in each hand) and no special tips are needed.

author: Ian.M
author_rank: Super Contributor
timestamp: November 27, 2021, 07:16:06 pm
content: The problem is the width of a JEDEC SOT23 package leg bend to leg bend is not well defined. Here's NXP's dimensions:https://www.nxp.com/docs/en/package-information/SOT23.pdfAdd up the tolerances, and you'll find that a bit that jams on the legs of a max lead length (NXP: HE) SOT23 with minimum flat end length (NXP: Lp- c, where c is the lead thickness) wont even land on the leg ends of a min. lead length package.Therefore you'd need a deeply slotted tip that could be bent to accommodate your specific SOT23 width across lead bends.

author: Geoff
author_rank: Contributor
timestamp: November 27, 2021, 11:33:59 pm
content: Quote from: Ian.M on November 27, 2021, 07:16:06 pmAs you say, it looks like the leg bend may be a problem.This bit from JBC C245658 looks to be the best fit, but while it will clear the package (it has a 2mm gape) it will jam on the leg bend.https://www.njr.com/electronic_device/PDF/package/SOT-23-5_E.pdfhttps://www.nxp.com/docs/en/package-information/SOT23.pdfThat said, with amply applied solder to bridge down to the pad, do you think it could do the job and even grip the part making it easy to remove?https://www.jbctools.com/c245658-cartridge-chip-20-l-product-1512.html

author: ledtester
author_rank: Super Contributor
timestamp: November 27, 2021, 11:41:47 pm
content: Reminds me of these videos:Desoldering without hot air -- Androkavohttps://youtu.be/CVsmwFAkf7IOne Hit Desoldering -- Androkavohttps://youtu.be/Hb9gWodVx7Y

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 12:13:26 am
content: Does anyone know of a video of these de-soldering tips that shows there use?I would very much like to see a video of an SOT23 being de-soldered using one of those tips from JBC or Hakko.

author: SteveyG
author_rank: Unknown
timestamp: November 28, 2021, 10:42:16 am
content: There's not much to it, just add a small amount of solder to act as a thermal bridge.

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 01:29:50 pm
content: Quote from: SteveyG on November 28, 2021, 10:42:16 amGreat, and thank you for your videos on the T3A and the T3B.These tips for de-soldering look to be a nice, clean, and reliable way to de-solder without risking damage to other nearby parts. But there is nothing online that I have found, about them.

author: Ian.M
author_rank: Super Contributor
timestamp: November 28, 2021, 02:32:36 pm
content: https://www.jbctools.com/c245150-cartridge-chip-22-s2-product-453.html2.2mm slot looks like a better choice. It still wont fit a max bend width SOT-23, as you'd need slightly over 2.5mm slot for that. If I were you, I'd measure the typical SOT-23 width across lead bends on a representative sample of the boards you intend to rework before ordering any bits . . .

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 04:41:02 pm
content: Quote from: Ian.M on November 28, 2021, 02:32:36 pmYour right about fitting over the bend of the legs, but that bit will not reach across all the legs (see e1 in attached).

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2021, 04:49:34 pm
content: I changed to using a heat gun in the 90's but procured a set of micro tweezers for home a few years ago along with a set of wide tips. They are much faster than the heat gun and easier on the board.Showing me removing SOT23s with a crude home made soldering iron. This is about is crude a setup as it gets.https://youtu.be/5Gjz6jqOiSQ?t=1097

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 05:44:22 pm
content: Quote from: joeqsmith on November 28, 2021, 04:49:34 pmThat is hardcore soldering, using a 100 Year old Clayton & Lambert Torch.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 28, 2021, 06:20:05 pm
content: Quote from: Geoff on November 28, 2021, 05:44:22 pmI was going to use an antique galvanometer to measure the temperature.

author: Ian.M
author_rank: Super Contributor
timestamp: November 28, 2021, 06:34:52 pm
content: Back to the O.P's problem, if there's at least one mm clear either end of the SOT-23,https://www.jbctools.com/c245268-special-15-product-446.htmlwith its 'arms' carefully spayed out to just fit over the package legs should work. As is its a 1.5mm gap between two 15mm long 5mm wide at the tip 'arms', so it wouldn't take much bending to open it out to around 2.4mm.

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 07:09:01 pm
content: Quote from: Ian.M on November 28, 2021, 06:34:52 pmInteresting idea.It would be helpful if there was some more details on using these nice JBC tips.

author: ygi
author_rank: Regular Contributor
timestamp: November 28, 2021, 10:36:08 pm
content: Just get a cheap chinese T12 knife or chisel tip (in the 3$ range) and slot it to your need with a dremel or whatever tool you have at hand.I mean, SOT23 isn't exactly the hardest package to desolder, there's no need to overthink this.

author: DavidAlfa
author_rank: Super Contributor
timestamp: November 28, 2021, 10:58:16 pm
content: Why so much drama about a sot23? You can perfectly remove them with a small solder blob, not killing either the board or the component.I've removed thousands of components much larger than a sot23 this way, like mcus, memory ics... Just get some practice with scrapped parts.

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 11:07:54 pm
content: Quote from: ygi on November 28, 2021, 10:36:08 pmIt might be good to have some cheap T12's on hand to hack for one off jobs. But a AUD$50 tip that lasts and can work in a densely packed board. And without risk to other parts, like plastic connecters for example, is worth the extra cost.

author: Geoff
author_rank: Contributor
timestamp: November 28, 2021, 11:19:54 pm
content: Quote from: DavidAlfa on November 28, 2021, 10:58:16 pmNo drama. There is a lack of info on these tips. And I tried the local supplier, but I've yet to get a response.Based on this discussion it does look like they are worth the extra cost.Thank you to all those who replied.

author: Ian.M
author_rank: Super Contributor
timestamp: November 28, 2021, 11:31:06 pm
content: It depends on how frequently you need to desolder SOT-23-3. For occasional repair work, simply lift the single pin with a bent mounted needle or fine tipped dental pick while heating it with an ordinary chisel tip bit (wide enough to bridge the other two pins when you do the other side), and wick off the solder from the lifted pin, possibly sliding a kapton shim under it, or prod it and check it flexes once its cooled, to guarantee its free, then heat up the other side and slide the SOT-23 off its pads.However if you've got thousands of them to do, e.g. a production run of hundreds of boards each with tens of the wrong part fitted due to an assembly or specification FUBAR and you've been left holding the baby, a dedicated desoldering bit would be a worthwhile investment.Ygi's suggestion of machining the tip of a bit to suit could work, but if you don't send it out to get the cut surfaces heavily nickel plated as a barrier layer, then hard chromed where you don't want it to wet, it will have a short life due to the exposed copper core eroding.

author: Geoff
author_rank: Contributor
timestamp: November 29, 2021, 12:11:41 am
content: Quote from: Ian.M on November 28, 2021, 11:31:06 pmMurphy's inverse law - if I get the tip and are ready, I'll never need to use it.

author: gnavigator1007
author_rank: Unknown
timestamp: November 29, 2021, 03:21:49 am
content: Was browsing cartridges earlier for my Pace station and came across their SOT-23 removal tip.https://paceworldwide.com/sot-23-removal-tipNot a whole lot of detail in the listing

author: Geoff
author_rank: Contributor
timestamp: November 29, 2021, 04:35:06 am
content: Quote from: gnavigator1007 on November 29, 2021, 03:21:49 amInteresting, the gape is only 1.8mm, so the tip is only on the legs.https://www.mektronics.com.au/pace-sot-23-removal-tip-0522.html

author: SteveyG
author_rank: Unknown
timestamp: November 29, 2021, 07:27:21 am
content: Quote from: ygi on November 28, 2021, 10:36:08 pmAs soon as you slot it, you'd be removing the plating on the area that you need to be wetted. It's doubtful it would work.

author: ygi
author_rank: Regular Contributor
timestamp: November 29, 2021, 01:49:52 pm
content: Quote from: SteveyG on November 29, 2021, 07:27:21 amRaw copper will wet as long as it's clean. Put flux on it before the initial tinning and after that, keep a blob in the slot. Obviously, it's not a tool up to professional standards but it would work to unsolder a few dozens sot23 once every blue moon.

author: thm_w
author_rank: Super Contributor
timestamp: November 29, 2021, 11:56:12 pm
content: Metcal version is basically the same (SMTC-105), 1.7mm gap (attached).Its great for desoldering the SOT23, but its close to useless for holding and installing them. So as Ian.m said, if you're doing a huge batch, I'dmaybeconsider using this tool to remove them all, then switch to something else to go and install the replacements.Hot tweezers are better for removing, holding, and installing the new part, as long as the width is wide enough to cover two legs. You can also use tweezers for 0603, 0805, etc. without needing to switch tips.

author: DavidAlfa
author_rank: Super Contributor
timestamp: November 30, 2021, 03:58:08 pm
content: If you cut it the copper will be gone in no time, there's a layer of iron on top of it for something.I don't know if it's been said already, you have the T15-R23 (T15 is how T12 is named for US market)

author: tooki
author_rank: Super Contributor
timestamp: December 01, 2021, 01:05:16 pm
content: Quote from: Geoff on November 28, 2021, 12:13:26 am6:15 in this ancient video shows it done using a Pace:https://youtu.be/M0wI-5YZQm4I agree with the other comments here: if the part is trash, just drown it in molten solder and pull it off. If not, use hot air.