hybridfree/eevblog-posts huggingface dataset:
Fit primary after Current transformer fitted to PCB? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 25, 2022, 11:23:58 pm
content: Hi,Doing 50:1 Current sense transformer for UCC28070A Boost PFC (60kHz). Each Booster is 1kW. Using E20/10/6 core.Pri and sec will not be terminated to former pins...instead we have pads on the PCB, right by the footprint PTH's.(Former fitted into its footprint PTHs, but not soldered to them , it gets tied down by nylon fishing line).Will only wind the secondary on the former, then fit the former to the PCB........Then, we will simply slip the primary round the core the one turn, and then solder the primary to the said PCB holes.Can you see anything wrong with this ploy?UCC28070Ahttps://www.ti.com/lit/ds/symlink/ucc28070a.pdf?ts=1658719626832E20/10/6https://www.tdk-electronics.tdk.com/inf/80/db/fer/e_20_10_6.pdf(ysing vert bobbin, and not the split bobbin)Pri is one turn of 7/0.3mm TEX-ELZSec is 50 turns of TEX-E 0.2mmPictures as attached.Do you think pri to sec coupling will be good enough like this?Also, the TEX-ELZ 7/0.3mm is said to be solderable, but trying to solder the ends to the PTH pads was less than easy (as pic shows)...also difficult to be sure that all the Enamelled strands have been soldered....do you have a better way?
Manufacturing Test Result Database and Visualization Software - Page 1
Forum section: electronics / general

author: adrianmc32
author_rank: Newbie
timestamp: July 25, 2022, 09:42:29 am
content: Hi FriendsI'm looking for good off the shelf solutions for managing manufacturing test result data.Currently we use an extensive custom solution but its maintenance is overwhelming.Most people seem to use custom solutions, but there has to be some good off the shelf stuff out there.Features Needed:- Test Specification Management- Test Result Data Collection- Test Result Data VisualizationThanks for your help

author: SMTech
author_rank: Frequent Contributor
timestamp: July 25, 2022, 11:28:15 am
content: I don't use it. But one piece of software( well I think its a huuge and expensive modular suite) that comes up again and again is Aegis Factory Logix. I think it can do literally everything that might be involved in manufacturing product. Data prep, data collection, test data, asset management, procurement, work instructions, compliance etc. I think its the brains behind many of the addon solutions you can buy when buying a surface mount line from most of the major vendors for example. However if you needs and industry justify or require that kind of traceability and analysis I don't think there's anything like it.https://info.aiscorp.com/factorylogix-production

author: kripton2035
author_rank: Super Contributor
timestamp: July 25, 2022, 11:59:05 am
content: going to a commercial software coming from a custom in house solution will always deceive you...because lots of things won't be present in the commercial app, you will have to get used to it.it would be a better idea IMHO to redefine the in house app from scratch, now that you know what works inside and what don't work.it would certainly also cost you less.ps: I do that kind of work in half of my everyday job.

author: SMTech
author_rank: Frequent Contributor
timestamp: July 25, 2022, 01:10:11 pm
content: Quote from: kripton2035 on July 25, 2022, 11:59:05 amEqually off the shelf products at a certain level often involve massive amounts of customization to integrate with existing systems or match your procedures instead of rewriting those procedures to match their own version if the "right way" of doing things. It still might be cheaper to hybrid a custom/off the shelf product than develop and maintain in-house however, as with anything else it depends on the value of your time, available skills, and how much of those things you have to spare on a non cash generating project...

author: Gribo
author_rank: Frequent Contributor
timestamp: July 25, 2022, 06:45:51 pm
content: I'm not using it, but evaluated it:https://www.wats.com

author: adrianmc32
author_rank: Newbie
timestamp: July 25, 2022, 10:04:30 pm
content: Well Said @SMTTechI think that perfectly describes the predicament I am in.Thanks or your thoughts.
Heatsink paste differences? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 19, 2022, 06:43:47 am
content: Hi,This heatsink paste is marked "hazardous".https://uk.farnell.com/mg-chemicals/860-4g/silicone-heat-transfer-compound/dp/2811968?st=heatsink%20paste..This one is not...https://uk.farnell.com/akasa/ak-455-5g/thermal-compound-cpu-5g-standard/dp/3498327?st=heatsink%20pasteDo you think the one not marked "non hazardous" really is that?

author: ebastler
author_rank: Super Contributor
timestamp: July 19, 2022, 07:39:13 am
content: Farnell provides the Safety Datasheets for both products right on the product pages you linked to. If you check the datasheet for the Akasa product (which Farnell has not labelled as hazardous), you will find the same warning as in the MG Chemicals datasheet: Very toxic to aquatic organisms. In addition, the Akasa datasheet warns of potential hydrogen release.So your suspicion is correct; the Akasa product is not safer than the MG one, and Farnell seems to simply have forgotten to list the warning on their product page.

author: wraper
author_rank: Unknown
timestamp: July 19, 2022, 08:05:36 am
content: None of them are hazardous as far as shipping companies are concerned. But goods containing liquid may get slapped this shipping restriction randomly.
source for 008004 (0201 metric) or 009005 (03015 metric) SMD resistors? - Page 1
Forum section: electronics / general

author: plingane
author_rank: Newbie
timestamp: May 22, 2021, 04:37:19 am
content: Does anyone know where I can actually buy size 008004 (0201 metric) or 009005 (03015 metric) SMD resistors? It would be helpful to even find out what manufacturers make these. I know Yageo does but they have an $11,000 minimum order. I've been searching to no avail. Even Octopart.com doesn't list them.

author: mon2
author_rank: Frequent Contributor
timestamp: May 22, 2021, 06:09:48 pm
content: 0201 metric is an industry standard footprint. It is rather small but very common.Check Arrow / Digikey / Mouser - each should have them.https://www.arrow.com/en/products/search?cat=&q=0201+smd+resistor&r=true

author: TimFox
author_rank: Super Contributor
timestamp: May 22, 2021, 09:28:47 pm
content: Those parts at Arrow are inch-dimension 0201 (0.020 in by 0.010 in), not the microscopic inch-dimension 008004.

author: SMTech
author_rank: Frequent Contributor
timestamp: May 23, 2021, 08:05:52 am
content: There appear to be a small number listed but not stocked @ Mouser but the lack of general availability is perhaps not all that surprising. Components that size are not something most people need and perhaps those that do are making very compact, high volume electronics recuing the number of contractors to a very select number all of who deal directly with manufacturer. Most pick and place machines don't handle 4mm tape or parts that small.

author: plingane
author_rank: Newbie
timestamp: July 14, 2022, 08:00:55 pm
content: Update a year later (in case anyone cares): Digikey now actually stocks three values of the Yageo RC0075xS series. Avnet shows available to order.KOA Speer sampled me 1,000 pcs of their RK73B1DTTX101J (100 ohm, 5%) 10 months ago so it is a real part, but they are very slow to respond to inquiries.ROHM has these smaller sizes supposedly available to order but they are all on allocation and not with distributors.Other manufacturers with at least data sheets are Cyntec and Topline.Please make inquiries so the manufacturers can see some interest.
Nylon 6/6 screws cause ESD problems to components on PCB? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 13, 2022, 05:33:21 pm
content: Hi,Have some control PCBs wired into a main PCB...the control PCBs stand on top of Nylon 6/6 screws as follows...https://uk.farnell.com/duratool/d01494/hex-threaded-spacer-nylon66-natural/dp/1733426?ost=1733426The internet seems to suggest that Nylon 6/6 is "ESD static dissipative"....https://www.copeplastics.com/materials/nylon-6-6-electrostatic-dissipative/..so i believe we will not inspire ESD problems to the components on the PCB just because of these Nylon 6/6 screws?

author: TimFox
author_rank: Super Contributor
timestamp: July 13, 2022, 05:38:51 pm
content: The material in your second link is not normal 6/6 Nylon, but Nylon infused with carbon fibers to become ESD-dissipative.Plain Nylon has a problem with moisture absorption, but is not particularly dissipative.See the full description:https://www.copeplastics.com/materials/tecamid-66cf20/I have used black polypropylene cable ties that were treated with carbon for UV resistance, but their DC conductivity was very low. The dielectric loss (at about 10 MHz) was substantial.The same manufacturer's green polypropylene cable ties did not show substantial dielectric loss.The hardware in your first link is not conductive: read the spec sheet for its very high resistance. Note that the material is natural 6/6 Nylon, not the specialized material in the second link.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 13, 2022, 06:11:49 pm
content: My mind fills with dread to begin to understand how captive hardware is being abused in such a way that it would be an ESD hazard.o.oTim

author: TimFox
author_rank: Super Contributor
timestamp: July 13, 2022, 06:38:50 pm
content: He thinks that plain 6/6 Nylon screws will dissipate ESD.Better to use brass.

author: thm_w
author_rank: Super Contributor
timestamp: July 13, 2022, 08:06:16 pm
content: Quote from: TimFox on July 13, 2022, 06:38:50 pmBut in reality it wouldn't matter. Its just a standoff to support a PCB, that is likely electrically connected to the board below it.Of course the information to determine this wasn't provided here, as usual.

author: TimFox
author_rank: Super Contributor
timestamp: July 13, 2022, 08:41:23 pm
content: No, he just looked at the headline from a Google search and didn't read the data sheet.

author: ebastler
author_rank: Super Contributor
timestamp: July 14, 2022, 02:52:09 pm
content: Quote from: Faringdon on July 13, 2022, 05:33:21 pmAs long as you don't rub those Nylon screws with catskin, you should be alright I think.
Does your P&P have an air filter? - Page 1
Forum section: electronics / general

author: TankSparks
author_rank: Contributor
timestamp: April 07, 2022, 04:16:51 pm
content: For P&P with builtin suction pumps, do they normally put a small filter after the nozzle. Is a filter required. Does a Neoden 4 have an airfilter?

author: jmelson
author_rank: Super Contributor
timestamp: April 08, 2022, 04:44:52 pm
content: Yes, both P&P's I have owned had filters between the nozzle and the vacuum/puff valve. When vacuum is on, it can draw lube oil and solder paste bits into the valve, which will cause sticking of the valve. My current P&P also has a n air filter before the vacuum venturi to keep comressor oil and debris out of the venturi.Jon

author: vstrulev
author_rank: Contributor
timestamp: September 02, 2022, 12:13:11 am
content: Quote from: TankSparks on April 07, 2022, 04:16:51 pmGood day. Take a look at my setup. There is a pdf file as well with the schematic of the whole setup. PNP is a pneumatic device with lots of parts. If you don't supply a clean air, it will eventually fail and there will be no point of fixing is as there are lots of pneumatic valves/vacuum pumt/etc.https://www.eevblog.com/forum/manufacture/yx-smt660-smt880-pp-machines/msg3977414/#msg3977414
Future Semiconductor. Are they reliable? - Page 1
Forum section: electronics / general

author: advark
author_rank: Contributor
timestamp: July 12, 2022, 08:05:11 pm
content: Hi everyone,I need a few LM35DT/NOPB (https://www.ti.com/lit/ds/symlink/lm35.pdf?ts=1657656253161&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM35%252Fpart-details%252FLM35DT%252FNOPB) temperature sensors to monitor heatsink temperature. The problem is that I can't find it anywhere. Nobody has it any in stock for quite a while and it won't be available until Q1/Q2 2023!Curiously enough, I found a chinese supplier (Future Semiconductor) that has 90K+ in stock at almost half the price of Digikey (min qty is not specified). So I'm wondering if anyone has any experience dealing with them. I fear those would be conterfeited or non-genuine parts (https://www.future-semi.com/parts/LM35DTNOPB_95e.html).At the moment, I'm stuck with TO-92 type has a replacement which is not ideal to stick on a vertical heatsink (OMNI-UNI-34-75), so if you known of any TO-220/TO-247 replacement to the LM35DT/NOPB, I'm buyingThanks

author: thm_w
author_rank: Super Contributor
timestamp: July 12, 2022, 09:24:15 pm
content: Lots on Aliexpress if you just need a few.What quantity? Future probably expects you to buy a few hundred or thousand.https://octopart.com/search?q=LM35DT&currency=USD&specs=0
Neoden YY1 Pick and Place - Page 1
Forum section: electronics / general

author: deanclaxton
author_rank: Regular Contributor
timestamp: July 06, 2022, 04:03:19 am
content: Neoden have posted videos showing a new low-cost PnP machine - the YY1. Looks interesting - pull type feeders like the low end Charmhigh, but much more compact with the reels underneath. Two heads with a nozzle change capability, 3000CPH with vision, under USD$3k and can handle 0201 apparently.

author: deanclaxton
author_rank: Regular Contributor
timestamp: July 09, 2022, 10:36:24 am
content: For under USD$3k this looks like a neat little machine for hobbiest/low vol usage.
Winding Boost PFC torroid with thick wire? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 07, 2022, 12:01:57 pm
content: Hi,I need to wind 42 turns of 1.25mm enamelled copper wire round two stacked Micrometals torroids (MS226026-2), without nicking the enamel of the wire.M2 226026https://powermagnetics.co.uk/wp-content/uploads/2020/04/Micrometals_Arnold-Catalog.pdfOD=58mmID=25mmHt=15mmI have tried just finger working the turns on, but is their a better way?Extreme finger muscles are needed to "hug" the wire against the torroid(s) and prevent slackness.

author: Zero999
author_rank: Super Contributor
timestamp: July 07, 2022, 12:10:08 pm
content: Is 1.25mm the crossectional area, radius or diameter?How about winding several strands of finer wire, to get the same crossectional area? Another option is to use flexible high temperature PTFE insulated cable.

author: Faringdon
author_rank: Super Contributor
timestamp: July 07, 2022, 03:33:31 pm
content: Thanks,Its the diameterhttps://uk.farnell.com/pro-power/ecw1-25/wire-47m-1-25mm-copper-enamelled/dp/1230986?ost=1230986Good point i think three strands of 0.71mm may be better...https://www.farnell.com/datasheets/3705631.pdfMost ones i rev eng'd have one strand of ~1mm, but it must be a machine that does that.....my fingers have welts in them now.

author: Zero999
author_rank: Super Contributor
timestamp: July 07, 2022, 08:33:18 pm
content: Quote from: Faringdon on July 07, 2022, 03:33:31 pmThree strands of 0.71mm diameter wire doesn't have the same or greater crossectional area as 1.25mm diameter wire. Remember a = πr2.

author: coppercone2
author_rank: Super Contributor
timestamp: July 07, 2022, 09:20:42 pm
content: You need partial molds (shaped like lemon squeezer kitchen tools) I think. I would glue the wire on one end with some epoxy to hold tension then put a turn on it and throw it over a special mold/arbor with a cutout on where you want to wind it.Not really sure if that would work perfectly but it might be a better start. Like a flared pipe. You might need more then one size once you get some turns on it. I think if you make it with a single wire it will be more robust/professional.

author: langwadt
author_rank: Super Contributor
timestamp: July 07, 2022, 09:28:42 pm
content: https://youtu.be/XTn72F0YBz4

author: coppercone2
author_rank: Super Contributor
timestamp: July 07, 2022, 09:30:53 pm
content: you also need a tool for holding the wire so you can pull on it good, the idea being that if you hold the tool strait it allows wire to pass, but if you tilt it, the friction jams it up so you can tug on it. I think you can make this out of a strong dowel with a notch
How do you get your PCBs when they are stuck in courier warehouse? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 07, 2022, 10:30:23 am
content: Hi,Do you know how to get your PCBs from China when they are stuck in the courier warehouse in UK?I ordered from China on 17th June. (~£250 incl shipping for 5 46x48cm PCBs, 5.9kgz package)China shipped it on 22nd June.It arrived in UK, and I got a message from courier saying delivery to my Mail Box had been attempted, but failed due to non payment of customs fees.On 4th July , I then clicked a link they (courier) sent me and payed the £57 customs fees.However, its still stuck in the warehouse.I phoned the courier but always just get the phone-bot, and it doesn’t help.Tracking website just says “In warehouse”, and has done since 4th July, its now 7th July.Is it worth just turning up at the courier warehouse to try and pick it up myself?

author: beanflying
author_rank: Super Contributor
timestamp: July 07, 2022, 10:38:31 am
content: Step 1 - GET A CLUEStep 2 - Don't start thread number 52 in the last 5 weeks because you failed at step 1.Step 3 - Still no Clue pay a professional to do your customs work.

author: wraper
author_rank: Unknown
timestamp: July 07, 2022, 10:46:18 am
content: You should at least mention which courier it is.

author: Faringdon
author_rank: Super Contributor
timestamp: July 07, 2022, 11:01:41 am
content: thanks, its a very well known coUrier. i Payed all the Shipping/fees etc.

author: cgroen
author_rank: Unknown
timestamp: July 07, 2022, 11:09:06 am
content: You could try and show up in front of the courier and make a small dance and see if that helps ?(See, my suggestion is pretty much as stupid as the question.....)
Class 1 Earth Testing In Production - Page 1
Forum section: electronics / general

author: Northy
author_rank: Regular Contributor
timestamp: July 07, 2022, 04:38:35 pm
content: Does anyone have any recommendations for equipment to test the earthing of a class 1 piece of equipment in a production environment?Ideally results will be stored automatically and traceable back to the serial number or some other way of identifying the particular DUT.How do others do it?Thanks,G

author: Mangozac
author_rank: Frequent Contributor
timestamp: July 08, 2022, 04:42:17 am
content: So an earth bond tester? We use a simple pass/fail unit but the much more expensive ones will do reporting the way you describe. Any particular reason for needing that level of traceability though?

author: SMTech
author_rank: Frequent Contributor
timestamp: July 08, 2022, 08:05:23 am
content: We used to print the test result for this kind of equipment and ship it with it, using a Seaward PAT tester, new models have barcode scanners, bluetooth connectivity, apps etc. You can define the suite of tests relevant to the product you are testing and then it steps you through it, logs the serial number etc. If you're running ISO or similar levels of traceability, logging that you have carried out the process and recording the result is the best way to make sure it was done and be able to demonstrate it was. We still use one of these but I'm pretty sure we've moved on from the hardcopy.

author: Northy
author_rank: Regular Contributor
timestamp: July 08, 2022, 10:39:03 am
content: Hi,Yes, I believe it's a requirement for safety approvals that the test result for each product should be recorded and traceable back to the item.Thanks,G

author: Northy
author_rank: Regular Contributor
timestamp: July 08, 2022, 10:41:12 am
content: Quote from: SMTech on July 08, 2022, 08:05:23 amHi thanks, yes that's pretty much what I'm looking at. I'm looking at recording the results in as easy way as possible while still being traceable back to the individual product.Thanks,G
Pace Soldering Desoldering SensaTemp & IntelliHeat Connections - Page 1
Forum section: electronics / general

author: Brians6
author_rank: Newbie
timestamp: July 06, 2022, 04:56:13 am
content: I have seen posts from some people that appear to know a lot about Pace equipment but I was unable to PM them.There were comments in other posts about the correct type of third party connector to use for a SensaTemp connector but no one verified whether the suggested connectors were the correct ones.Can someone who has used third party connectors for Pace please state if the connectors were for SensaTemp or Intelliheat, what brand & part number they used, if they appear the same as the Pace ones, & if they have the locking capability?I’m about to receive a MBT 350 off eBay Australia for a bit over AUD $500. It will be a major upgrade for me but I have the older SensaTemp items so I will need to make or get Gender Bender Adaptors to change for the IntelliHeat to SensaTemp. Those adaptors are more than AUD $80 plus shipping each so I am looking at making them if I can. I'm an ex-military pensioner so if I can save a few dollars on them I will. That is why I wish to find out about connectors.I will have to try & work out the wiring for an adaptor too, if I can get the plugs & sockets.If it is possible to get the parts then I was even thinking of making an adaptor panel to mount on top of, or on the side of, the MBT with a lead to the front socket for each channel going to panel mount sockets for BOTH IntelliHeat & SensaTemp so that I can just plug anything in.I saw the post on DIY ISB SetBack Cubbies so I will probably make one of them up as well while I am at it.Many thanks,Brian.
Compact SMA connector PCB surface mounting? - Page 1
Forum section: electronics / general

author: Martin F
author_rank: Regular Contributor
timestamp: July 05, 2022, 11:52:59 am
content: Hi all,We're developing a new IoT product which will have LTE and GNSS SMA connectors for antennas.The SMA connectors should ideally be compact, low cost and possible to surface mount at our PCBA.Currently, we are testing with the below model from Molex:https://www.molex.com/molex/products/part-detail/rf_coax_connectors/0732511142This connector costs around 1.5 EUR, is easy to mount during our PCB assembly process and takes up very limited space inside the device.However, the SMA connector is also very short. It extends ~6.6 mm beyond the edge of the PCB. With a 1.5 mm enclosure wall-thickness, the externally exposed part of the connector is ~5.0 mm. To be able to mount a relief hex nut and to secure some clearance between the enclosure (+nut) and a fully inserted antenna, we need the external part of the connector to be > 8 mm. The total length from PCB edge should be > 9.5 mm.The challenge is that we are simply not able to find SMA connectors with a similar design as our current model, which also support the longer connector. Connectors that do support the longer length seem to require manual mounting - or they take up a lot of space on the PCB (e.g. various 'through-hole' options).Do any of you have specific suppliers you recommend we check out (we've reviewed e.g. Molex, Linx)?And do some of you have specific SMA connector alternative part numbers that you know of that are similar to the Molex one - but with longer SMA connectors?Thanks!

author: mon2
author_rank: Frequent Contributor
timestamp: July 05, 2022, 12:54:44 pm
content: Try this vendor - they may be able to help:https://www.renhotec.com/sma-connector/

author: langwadt
author_rank: Super Contributor
timestamp: July 05, 2022, 01:18:59 pm
content: I think the keyword is bulkheadhttps://uk.rs-online.com/web/p/coaxial-connectors/7123254
"Arc lighters" and surface treating plastics for better adhesion? - Page 1
Forum section: electronics / general

author: e100
author_rank: Frequent Contributor
timestamp: June 26, 2022, 02:44:53 am
content: Has anyone used one of those electric lighters gadgets for surface treating hard to glue plastics such as PVC?I don't want to burn the plastic, just change its surface chemistry.https://youtu.be/voTVI0bL9C4?t=153Are these things deadly to electronics?

author: Uunoctium
author_rank: Frequent Contributor
timestamp: June 26, 2022, 03:28:43 am
content: due to lack of purge gas flow this is not an cold plasma what's normally used for etching!With such an arc lighter you will immediate burn plastics - too hotbut you can modify ithttps://siamagazin.com/a-cold-fire-torch-that-you-can-touch-and-not-get-burned-explained/

author: e100
author_rank: Frequent Contributor
timestamp: June 26, 2022, 04:37:34 am
content: Quote from: Uunoctium on June 26, 2022, 03:28:43 amLooks complicated to build and needs an argon or helium supply.Would a normal stream of air going through the discharge of an arc lighter still allow the arc to form but keep it cool?

author: Marco
author_rank: Super Contributor
timestamp: June 26, 2022, 06:57:50 am
content: I'd be scared of that electrode arcing to my finger in that demonstration in the video, the plasma might not burn it but a HF arc can be nasty.

author: twospoons
author_rank: Frequent Contributor
timestamp: June 27, 2022, 05:03:03 am
content: Quote from: e100 on June 26, 2022, 04:37:34 amIts not really. Simple 2 transistor push/pull oscillator built around a tv flyback to give ~20kV @~20kHz.Quote from: e100 on June 26, 2022, 04:37:34 amAir works just fine. Probably even better for surface treating plastics - all those oxygen radicals do a great cleaning job.Ideally you want to set this up for dielectric barrier discharge.Years ago I built a low pressure version for treating LCP, and the increase in glue bond strength was incredible. LCP is one of those difficult plastics.

author: e100
author_rank: Frequent Contributor
timestamp: June 27, 2022, 06:34:58 am
content: How about an ozone generator. Is this the same principle with electrodes separated by a dielectric?https://youtu.be/yfmWGl1DRWI?t=195

author: jpanhalt
author_rank: Super Contributor
timestamp: June 27, 2022, 09:48:18 am
content: One can and I have used simple flame treatment with a propane torch. That's an old technique. There are lots of articles on it. Here's one of the first to pop up on my search:https://www.sciencedirect.com/topics/engineering/flame-treatmentFor Teflon, I use a chemical etchant.

author: Marco
author_rank: Super Contributor
timestamp: June 30, 2022, 08:57:09 pm
content: Quote from: e100 on June 27, 2022, 06:34:58 amSame principle, but ozone accumulates across that tube and plasma is already gone by the time it gets to the output. A cold plasma torch has to generate the plasma very close to the exit.
Temperature resistant, strong nylon wire to tie down inductors? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: June 28, 2022, 11:24:22 am
content: Hi,I have 2kW offline Proto PCB.....big torroid inductors for PFC.....need tie-ing down to PCB.....stop them moving about....i have NPTH's in PCB...now seek strong, temperature resistant, electrically insulating "wire" to tie the torroids down.Will fishing line be OK? What do people use for this?This is purely for prototype only.Fishing line 0.5mmhttps://www.amazon.co.uk/HCFGS-Fishing-Tension-Monofilament-Tensile/dp/B07XJNJN28/ref=asc_df_B07XJNJN28/?tag=googshopuk-21&linkCode=df0&hvadid=399647712860&hvpos=&hvnetw=g&hvrand=16761693699491400875&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006886&hvtargid=pla-836317726001&psc=1&tag=&ref=&adgrpid=88836927967&hvpone=&hvptwo=&hvadid=399647712860&hvpos=&hvnetw=g&hvrand=16761693699491400875&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006886&hvtargid=pla-836317726001

author: Berni
author_rank: Super Contributor
timestamp: June 28, 2022, 11:36:58 am
content: Zipties are one popular way of doing it.Even the normal zip ties should handle boiling temperatures without a problem, but you can also find more specialized zip ties that are designed for more hostile environments because they are made from special high temp/ high chemical resistance plastics.

author: coppercone2
author_rank: Super Contributor
timestamp: June 30, 2022, 04:03:57 pm
content: how about a nylon bolt and washer? I think threading into a riveted PCB insert would be best.
TSSOP breakout by hand - Page 1
Forum section: electronics / general

author: josuah
author_rank: Regular Contributor
timestamp: June 29, 2022, 08:43:07 pm
content: WARNING: The following post contains graphical content that could hurt the sensibility of engineers who appreciate professional-looking results with no mark of handcrafting.I am waiting packages for TSSOP breakout boards and photoresist for etching, the toner from my printer is not soluble to acetone and gave terrible results, so did the thermal transfer method, and no CNC or laser engraver around, redrawing the traces with a sharpie was not accurate enough, and I love complaining as you see.This looks bad, but it works!1. Sand a blank single-side PCB: full of copper, not etched.2. With a cutter, cut a rectangle of the exact size of the TSSOP minus the pins, so that the pins are not connected to the ground on the middle of the chip.3. Solder the TSSOP chip to it. It will be very easy.4. Remove as much extra solder as you can from around the chip with a soldering iron by dragging it away.5. Sand each side of the TSSOP to remove the extra tin6. With a cutter, cut lines on each side of the TSSOP to split the copper between each pin, and have tracks.7. With a cutter, keep these lines going but widen then until you arrive to 0.1" (2.54mm) pitch (convenient for breadboards) until the edge of the PCB.8. Drill holes between these 0.1" lines, put pins through, solder them.You end-up with the worst-looking dev board possible to make.Please, forgive my madness.

author: josuah
author_rank: Regular Contributor
timestamp: June 29, 2022, 08:49:24 pm
content: Other madness I have tried but did not work:1. Solder small copper wires one by one to the chip.2. Solder the chip on a grid of wires as presented on the image below.Flux party in both case, and I believe the reason it failed was the wrong solder tips: too big or too small.For (2.), the idea is building-up a grid thin enough by attaching copper wires to headers, then shifting down one of the header: the pitch between the wires goes down as one of header is translated.Shortly after, on another project (top post), I discovered the wonders of the chisel soldering tip./

author: josuah
author_rank: Regular Contributor
timestamp: June 29, 2022, 08:51:55 pm
content: In case you happen to work for SIliconLabs:> No EFM8BB51 was harmed in the process of this experiment.
Do you ask for "electrical test" with PCBs? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: June 26, 2022, 01:54:28 pm
content: Hi,When you order PCBs from China and the selector offers you "electrical test"....is it worth selecting it?....i am speaking of just standard offline SMPS PCBs.Is it worth selecting any of the test methods offered?

author: ebastler
author_rank: Super Contributor
timestamp: June 26, 2022, 02:36:14 pm
content: With the low-cost Chineses PCB houses I have used, the cost for electrical testing is zero. Hence yes, it's worth selecting it.

author: Faringdon
author_rank: Super Contributor
timestamp: June 26, 2022, 09:58:41 pm
content: Thanks, what if you choose the option with no testing or inspection...is that a bit dodgy?......(just so i can gauge it, i appreciate its so low price its worth getting testing)

author: Gyro
author_rank: Super Contributor
timestamp: June 26, 2022, 10:04:25 pm
content: Is spending your time (and parts) building a prototype board, only to find that there are one or more unknown shorts or opens a bit dodgy?

author: Faringdon
author_rank: Super Contributor
timestamp: June 26, 2022, 11:56:01 pm
content: Thnaks, may i ask, what do you think the chances of that might be, ie, if you didnt select the test/inspection thing?

author: ebastler
author_rank: Super Contributor
timestamp: June 27, 2022, 06:51:04 am
content: 1.24% * board area  / (track spacing )².I just made that up, ignore it. But seriously -- the probability will depend on so many aspects of your board design and the manufacturing details, I don't think anyone can give you solid numbers.Some low-cost vendor I ordered from a few years ago would typically send 11 or 12 PCBs when I ordered 10, which suggests to me that they expected one or two failures out of 10. That was for small, double-sided boards. Manufacturing processes may have improved since, but the fact that flying probe tests are still part of the standard offering indicates that the failure rates are not negligible.Yours is a large 4-layer PCB, if I remember correctly. You will put a lot of time into populating it and bringing it up, and the parts will cost you money as well. There are more than enough things that can go wrong and cost you time to troubleshoot. I would not want to potentially lose days, plus the cost of having to build a second unit, due to some internal short on the board.

author: jc101
author_rank: Frequent Contributor
timestamp: June 27, 2022, 04:06:02 pm
content: I'd turn the question around, when would you not have PCB electrically tested to verify all the nets are valid and there are no shorts?
WLSCP/BGA package mount for testing without soldering - Page 1
Forum section: electronics / general

author: Chrische
author_rank: Newbie
timestamp: June 19, 2022, 07:37:45 pm
content: Hej Everyone,I got a custom ASIC in a WLSCP package. The thing is tiny: 0.5mm pitch, 0.25mm bump diameter, with a total outline of 5.3x3.2mm.I will receive a handful of them and would like to be able to test them on a evaluation board.Since I do not have access to some professional solutions, i would like to get some advice on solutions, where I don't have solder the ASIC onto test board.The best idea that I have come up with so far, is to create a custom holder, where outline of the package will just fit into.Then i would apply some pressure from above to make contact with the PCB. Has anyone tried something like this with a bga perhaps?I'm curious to hear any ideas of how to approach this.

author: jeremy
author_rank: Super Contributor
timestamp: June 19, 2022, 11:19:34 pm
content: I have seen this used before:https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=1640905&DocType=CD&DocLang=ENbut I am assuming it is out of your price range. Similar tech here:https://www.ironwoodelectronics.com/products/bga-sockets/

author: jmelson
author_rank: Super Contributor
timestamp: June 20, 2022, 02:05:19 am
content: Check with Ironwood Electronics, they make test sockets for a wide range of parts. But, they are NOT cheap.Jon

author: Kasper
author_rank: Frequent Contributor
timestamp: June 26, 2022, 07:37:14 am
content: Before trying a custom holder, it's probably easier and cheaper to buy a used toaster oven and try that with flux, without stencil or paste. No guarantee it'll work very long or at all but it has worked for me with a $80 board and a $25 toaster oven.

author: Kasper
author_rank: Frequent Contributor
timestamp: June 26, 2022, 07:38:49 am
content: Stencil and paste would be better but it sounds like you want cheap and easy, so this could be a starting point.
Cost of aluminium heatsink - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: July 25, 2022, 08:30:36 am
content: Hi,Do you know a cheap place to order aluminium plate from? (pref near London , UK but not necc, if postage is cheap)Approx 1cm thickness. 30cm by 20cm...doesnt need to be finned.Our local Metal company just quoted me £216 for a 20cm by 20cm by 15mm piece of aluminium....that includes "cutting services" they tell me.Even here its £84 for a 30cm by 20cm piecehttps://uk.farnell.com/fischer-elektronik/sk-56-200-sa/heat-sink-alum-extruded-0-3k-w/dp/1211722Just needs to be flat plate to hold the seven HSC100 power resistors for approx 500w....will put a fan blowing over it all too.HSC100 resistorhttps://uk.farnell.com/cgs-te-connectivity/hsc10047rj/resistor-100w-5-47r/dp/1174294?st=hsc100Its only for a test jig, dummy load

author: Gyro
author_rank: Super Contributor
timestamp: July 25, 2022, 09:02:39 am
content: One time that ebay is your friend. I often use ebay sellers for metal stock...eg.https://www.ebay.co.uk/itm/281757264594(just at random)P.S. 30cm wide by 20cm long ismuchcheaper (than 20cm wide by 30cm long - £36 vs £56)

author: Kean
author_rank: Unknown
timestamp: July 25, 2022, 09:32:27 am
content: If it doesn't need to be pretty, then visit your local scrap metal place and see what they have. Usually these places have bins of random stuff waiting for recycling, and sometimes keep nicer pieces aside.Keep in mind that a 300x200mm plate of 15mm thick Aluminium is not going to be ideal for a 500W dummy load. You actually need surface area rather than thickness so that air flow can remove the heat. Otherwise you are mainly relying on the thermal mass, which will only last for so long before the whole thing gets darn hot. Heatsinks have fins to increase the surface area to allow quicker removal of the heat.An aluminium plate of 300x200x15mm at estimated 2800 kg/m3 (depending on grade) is approx 2.5kg. Aluminium (again depending on grade) has a specific heat capacity of approx 900 J/kg.K.After 5 minutes (300 seconds) at 500 W you have supplied 150 kJ of energy. Your metal plate will have risen in temperature by roughly 67 K and any cooling by air flow will be limited by the minimal surface area.

author: pcprogrammer
author_rank: Super Contributor
timestamp: July 25, 2022, 09:48:10 am
content: If it is just a test rig, you could also use separate and smaller pieces of cheaper scrap you can find. Might even improve the cooling of the individual resistors. Sure might be a bit more work, but could save you some money.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 25, 2022, 09:57:48 am
content: Heatsink companies get raw stock of extrusion they saw, mill and anodize for you.The price is for the customization.For example, a small heatsink we bought like Sk407 15cm milled costs €75.Buy catalog heatsinks if you can't afford the custom price.
fpc connector, slide lock? How does it work? - Page 1
Forum section: electronics / general

author: julian1
author_rank: Frequent Contributor
timestamp: June 15, 2022, 07:17:07 am
content: I cannot figure out how this FPC connector is supposed to work, even having the damn thing in my hand.https://www.digikey.com.au/en/products/detail/te-connectivity-amp-connectors/4-1734839-0/2180502?s=N4IgTCBcDaICwFoCMB2AzHAHGgnAgDCALoC%2BQApdf datasheet drawing,https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=1734839&DocType=Customer+Drawing&DocLang=EnglishIt is supposed to be "Slide Lock"Does that means it slides open somehow?Or is the flex pushed into it, and that is what constitutes the sliding lock?Also, are connections supposed to be made top-side or bottom side or both sides of the flex?

author: darkspr1te
author_rank: Frequent Contributor
timestamp: June 15, 2022, 07:18:59 am
content: There are two tags on the outer edges that you pull on to unlock the connector.darkspr1te

author: julian1
author_rank: Frequent Contributor
timestamp: June 15, 2022, 07:28:55 am
content: Ok, Thanks I got it. It pulls apart in the same direction that the flex travels. Even having pulled the thing into pieces it wasn't clear.

author: eugene
author_rank: Frequent Contributor
timestamp: June 15, 2022, 01:14:28 pm
content: Thedatasheetseems to indicate that something flips up.EDIT: looking closely at the figure just causes more confusion. In the center figure, the one with something rotated 20 degrees, the terminals that solder to the PCB are on the right. ?EDIT 2:This sell sheetseems to suggest that it's what TE calls a "stuffer actuator" as darkspr1te said. Now I'm curious about the angle shown in the figure in the datasheet...

author: julian1
author_rank: Frequent Contributor
timestamp: June 15, 2022, 10:42:14 pm
content: The drawing with the angled cam confused me also. It suggests a kind of tilting lid style connector which I have seen before. But the drawing orientation/viewpoint implies the range of travel extends below the pcb surface.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: June 19, 2022, 10:12:46 am
content: Quote from: eugene on June 15, 2022, 01:14:28 pmI'am not 100% sure but i think it's saying that if this connector was mounted at the edge of the pcb (where pins are top right) then the latch with be loose when open and have 20deg of movement up and down where if you mount fully on the pcb that movement will be restricted by the pcb itself .darkspr1te
PCB manufacturing thickness tolerances - Page 1
Forum section: electronics / general

author: Skerved
author_rank: Contributor
timestamp: June 17, 2022, 07:37:55 am
content: We have a product design that is rather sensitive to the final PCB thickness. I know I should probably try to do a redesign that eliminates this issue, but at the moment that is not possible.So what I want to ask for advice on are PCB manufacturers and possibly manufacturing techniques that give better final thickness tolerances than the standard ±10%. Can anyone point me in the right direction?

author: jmelson
author_rank: Super Contributor
timestamp: June 17, 2022, 03:31:53 pm
content: Wow, I suspect 10% is a cover your backside number, not an actual spec of what is manufactured, at least for double-sided boards. Now, for multilayer, I suspect the finished thickness could vary a bit more due to the laminating process.Jon

author: thm_w
author_rank: Super Contributor
timestamp: June 18, 2022, 12:49:35 am
content: Probably ask your preferred manufacturer what they can do.Otherwise the spec is noted here:https://madpcb.com/tolerances/QuoteMaybe someone with IPC-2222A can find itQuoteAnother option might be to make it thin and then shim it.

author: Skerved
author_rank: Contributor
timestamp: June 21, 2022, 06:44:54 am
content: We have had panels delivered close to or even over 10% plus. If it's outside tolerance, we can of course get them replaced.The more I look, the more it seems like this is not a common request. We'll meet with our supplier to see what we can come up with.Thanks for now!
recommended connectors for pin in paste / through hole reflow or press fits? - Page 1
Forum section: electronics / general

author: loki42
author_rank: Frequent Contributor
timestamp: June 19, 2022, 06:38:55 am
content: I'm contemplating reflow soldering some PTH parts. I'd also be open to press fits. Does anyone know of good / cheap / PiP compatible IDC, 3.5 mm TRS jack, 1/4" jack connectors and 2.1 mm barrel jack power connectors? What should I look for if trying to see if they'll survive reflow? I tried some Neutrik connectors using SAC305 GC 10 in our previous oven and melted them. Would it be worth switching to low temp paste (Bi or something else, lead free only).I've got gear for press fits if that's a better option / possible.
Boards with no bottom resist? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: June 17, 2022, 08:26:30 pm
content: Hi,I just sent off gerbers for a 4 layer SMPS PCB to PCB train in Ireland. Components are only on one side....all is through hole....daughter boards hold the SMD.I forgot to send off the "bresist" layer in the gerbers.I also forgot to add the component designators to the topsilk layer....So do you think they will put solder resist over all the bottom side pads and make it unsolderable?

author: IconicPCB
author_rank: Super Contributor
timestamp: June 17, 2022, 09:04:00 pm
content: Of course You can and should.The sooner the better as it minimises the effort the factory puts into the half arsed task.The solder mask is among the final additive stages of production and there shouldn't be too much cost associated with the early engineering work changes brought on by addition of new data layer,

author: jpanhalt
author_rank: Super Contributor
timestamp: June 17, 2022, 09:45:30 pm
content: If you are using Eagle, through hole pads should protect the bottom (solderable) layer from getting resist over those pads. Frankly, I have never done that (sent without proper bottom layers). Check what layers show on the bottom layers. However communication with your boardmaker should take precedence over worrying about it here.
conformal coating for HP 8350 solder mask repair substitute? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: June 15, 2022, 08:16:29 am
content: So I had a 3x AA battery pack go off inside of a HP8350 generator that I got on ebay, and the solder mask coating on all the thicker traces is screwed up.When I started to clean up the residue, basically all the solder mask on thicker traces started to come off, and the planes are totally exposed now. (after cleaning it started coming off like sunburn on any trace wider then 1mm, and the traces with battery chemical damage are spotty, but the solder mask adheres better here)Since its a big backplane PCB and it has connectors soldered to it, I need a conformal coating that I can carefully paint on with a brush.The PCB is large, around 2sq feet and has a gold finish. I thought to use a MG chemicals product, but I am not sure what the best one would be. I thought about the 4200UV coating, which is UV triggered.https://www.mgchemicals.com/products/conformal-coatings/uv-conformal-coatings/uv-cure-conformal-coating/Is this a good choice? I hope these coatings can be put on bare gold finish without having a solder mask...? It is just a interconnect board, there are only some gold pins and cinch connectors on it.

author: SMTech
author_rank: Frequent Contributor
timestamp: June 15, 2022, 12:24:07 pm
content: I'd just slap some TRV on it ...

author: coppercone2
author_rank: Super Contributor
timestamp: June 17, 2022, 06:08:46 am
content: where you get that? sounds like some jungle warfare shit lol, read for the patrol boat

author: coppercone2
author_rank: Super Contributor
timestamp: June 18, 2022, 01:51:51 am
content: wow that green ebay solder resist is some real tomato paste bullshit, what a wastei should have just used paint lol, it might have came out OK

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 18, 2022, 02:02:44 am
content: I think SMTech meant RTV, like automotive silicone, perhaps they misunderstood the question. Personally I'd be inclined to just leave it be, especially if I'm understanding right and the exposed copper still has gold over it. This is a bench instrument that shouldn't see corrosive or condensation prone environments.

author: coppercone2
author_rank: Super Contributor
timestamp: June 18, 2022, 03:02:06 am
content: nah TRV is a thing its tropicalized varnishI haphazardly squegeed the green crap on most of the gold. Problem is I got some on the capacitor screw holes but it looks like those use crown washers , so if there is a slight amount of residue it should be OK. its very hard to get off completelyI think its a good idea in case a capacitor leaks