Never assume anything about parts and how they change - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 04, 2023, 04:46:14 pm
content: Not a question, but I wanted to share my experience here if only to get it off of my chest.I was using a part for a cable on my board, the Molex 73412-0110 UMCC Coaxial Connector back in 2020 at first. It's a simple coaxial receptacle, and from the STL file that I downloaded back then, the side with the signal pin was indicated with an angle/notch. That's very clear from the STL file that I use to model my projects.I've been using it like that for the last 3 years, and there were no problems.....up until now. I requested the same part be used for an assembly that I outsourced to a company. To my surprise, the part changed. As of now, instead of the signal pin being on the side with the angle/notch, it's now on the opposite side of that. I verified that with the datasheet (released back in 2022). Therefore, on my latest board, it's as if my input was shorted to ground as a result of this assumption.Annoying how one little change can cause so much trouble. However, I suppose that there's a lesson to be learned here to never blindly trust the parts you used for so long. Still, that's so weird that they would make such a change like that.

author: mwb1100
author_rank: Frequent Contributor
timestamp: August 04, 2023, 05:24:31 pm
content: You'd think they'd at least tack an "A" or something to the part number to give at least some indication that there was a a change of that nature.-https://media.digikey.com/pdf/PCNs/Molex/PCN511407.pdf

author: mikerj
author_rank: Super Contributor
timestamp: August 04, 2023, 05:42:21 pm
content: That is pretty naughty IMO. I see that they changed the orientation of the devices in the tape so a dumb pick and place would have put them down in the correct orientation, but if the silkscreen showed the corner notch an observant operator would have picked that up and "fixed" it.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 04, 2023, 06:42:09 pm
content: Quote from: mwb1100 on August 04, 2023, 05:24:31 pmThanks for this. That reveals so much. Seriously, what kind of customer requests/complaints did they have that necessitated such a change?...do my eyes deceive me, or do I see some Korean characters in that image?

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 04, 2023, 06:44:30 pm
content: Yeah, my silkscreen had the notch. Though, who would have anticipated such a change? Maybe I'll have to retool my silkscreen lines to make it a square for neutrality and use something else to indicate the signal pins. Pick-and-place machines should be able to sort that out, right? (Though, when I left assembly to someone else, I told them that the silkscreen notch was the correct orientation. Maybe that's on me then)

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: August 05, 2023, 02:25:22 pm
content: > Date Issued : April 01, 2022With this date, the poor quality rasterised images, and just the feel of the thing, you'd think it was a low-effort third-party April Fool's joke.Nope.Here's a more detailed version of the PCN, including presentation slides with LG branding (Molex's CM for this part? Would explain the Korean).The best part from the slides: "The new 73412-0110 can be used on existing customer’s PCB layout , it’s not affected". Technically correct: the best kind of correct.

author: MrAl
author_rank: Super Contributor
timestamp: August 05, 2023, 04:16:17 pm
content: Quote from: LoveLaika on August 04, 2023, 04:46:14 pmHi,Is this the new drawing?If so, look in the upper left hand corner of the drawing. You'll see an arrow with the word "NOTCH", which is on the UPPER RIGHT HAND corner of the part itself.Are you saying that now they put the notch on the LOWER LEFT HAND corner?That would cause the part to be rotated by 180 degrees which would reverse the ground and signal pins.If that's the case, i would contact the company to find out what the hell is up with that. It seems like they are following suite on what software makers often do: change things any way they feel like it regardless of what happens to other companies' software.Can you verify this or show another drawing?

author: mikerj
author_rank: Super Contributor
timestamp: August 05, 2023, 10:56:56 pm
content: These are the files I found, revision "C17" to revision "D" clearly shows the corner notch has moved to the opposite corner of the part.

author: Eraldo
author_rank: Regular Contributor
timestamp: August 05, 2023, 11:18:11 pm
content: I find this part hilarious

author: MrAl
author_rank: Super Contributor
timestamp: August 06, 2023, 11:45:10 am
content: Quote from: mikerj on August 05, 2023, 10:56:56 pmHello,That's what i suspected. Something changed over the course of about 10 months.Why does this smell like class action lawsuit. Do you realize how many products already in production this could affect. They effectively made the PC boards obsolete for the manufacturers that use this product.Does it say anywhere that specifications are subject to change at any time without notice.If you ask me, this shows an extreme lack of integrity on behalf of the company that made these parts. Since that causes such an extreme change in the mounting of the part, this is almost like changing the number 1 pin of a 7400 TTL chip to what is now pin 8. It almost sounds like something a crazy person would do because that one small change could require a complete re-routing of the traces on the PC board, or at least a change to a set of drawings.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 07, 2023, 01:50:55 pm
content: Quote from: MrAl on August 05, 2023, 04:16:17 pmHello Mr. Al. Yes, the attachment that you provided is indeed the new drawing. As you can tell from it, the notch is at the top-right corner of the part when you look at it from the top oriented as such. However, looking at the bottom of the part as shown in the drawing at the bottom right there, the side with the notch is no longer the Signal pin, but it is the ground pin. Also, notice the date on the document: 2022/07/20. That's when this revision was made.Unfortunately, I don't have any documents to compare it to. Really, I should be keeping track of all the components I've been using by holding on to their datasheets, but I never saw the need to. All I have is this STP file for the 3D model. I downloaded this when I was first using the part. Looking at it in FreeCAD, you can clearly see the model having the notch on the side with the signal pin.

author: mwb1100
author_rank: Frequent Contributor
timestamp: August 07, 2023, 03:53:47 pm
content: They should have modified the part number (add an "A" or whatever) to indicate an important change like this. In essence they swapped the function of pin 1 and pin 2. Even though the part is functionally identical, it's still something that people should be forced to check if the change impacts them.A change notice that doesn't get sent to all customers isn't enough.

author: mikerj
author_rank: Super Contributor
timestamp: August 07, 2023, 05:47:33 pm
content: Quote from: LoveLaika on August 07, 2023, 01:50:55 pmI attached a previous revision of the datasheet a few posts up.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 07, 2023, 08:39:29 pm
content: Thanks. I appreciate that. But what I meant was that I didn't have a copy of the datasheet on my local drive.

author: MrAl
author_rank: Super Contributor
timestamp: August 08, 2023, 11:53:12 am
content: Quote from: LoveLaika on August 07, 2023, 01:50:55 pmHi,Yes I see what you mean, and I also see that someone else posted the two drawings you can check them out if you like. I did, and i see where the change came in but do not see any part number change just like you and others here.The DRAWING revision changed, but not the part number.That's one of the stupidest things I've ever seen in all my years. However, things in this field and others have gotten stupider as time went on. I have a feeling it was brought on by the software evolution where you can put out some software that doesn't even work right, then simply modify it later as an "update".It never used to be like this. Products either worked or they didn't work. If they didn't work, you brought it back.With this kind of trend, designers are probably getting used to making mistakes and not worrying about it too much because that's the trend now. Only those with high enough integrity are going to do it right, and luckily there are still some left, for now anyway.This company needs to be told about this and the impact it has on other manufacturer's product lines. This is a very important issue in my view.This also brings up another question, maybe even more important and significant.What happens if you order a part from outlet A and they have some of the 'older' parts in stock and they send them, but they also have some of the 'newer' parts in stock, and they send some of them with the older ones. Now you get some older parts with the first orientation of pins, and some newer ones with the second orientation of pins. How do you know which ones are which, so how do you know how to tell the setup machine how to place the parts. You may have to have a hand assembler place the parts and solder by hand because they would have to examine each and every part before it is placed, and they would have to know what to look for in order to do that effectively. That also means the possibility for error and rework comes up as well.This is truly a crazy issue.

author: MrAl
author_rank: Super Contributor
timestamp: August 08, 2023, 12:01:12 pm
content: Quote from: mwb1100 on August 07, 2023, 03:53:47 pmHi,Yes I agree the part number should and must be changed. Otherwise you don't know if you are getting an older part or a newer part, and that means you can't be sure how to place it without examining the part by eye.How would the parts outlet (like Digikey) even know what drawing to show on their website, or even be able to tell which part they got.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 08, 2023, 04:05:53 pm
content: What interests me is that there could be other parts affected in such a way. If such, and there are more users affected as such, it feels like class action territory.Once I found the issue with my part, I had a look at Digikey to see what alternatives there were that had the older orientation. To my surprise, a lot of other parts also had the same change. You can see this by looking at TE Connectivity's part onDigikeyand in in theirdatasheet. I mean, I suppose if one manufacturer made such a significant change, others would do the same as well to ensure their part follows the change.

author: MrAl
author_rank: Super Contributor
timestamp: August 09, 2023, 09:44:15 am
content: Quote from: LoveLaika on August 08, 2023, 04:05:53 pmThings in these fields just keep getting stupider and stupider.This kind of change kind of makes auto insertion equipment obsolete.

author: MrAl
author_rank: Super Contributor
timestamp: August 12, 2023, 10:55:34 am
content: Hello again,I found out something interesting about this issue but I would hope someone here can take the time to verify this information.It is true that the notch on the part has changed the orientation by 180 degrees and that means that if you or a machine goes by the placement of the notch the part ends up getting installed and I presume soldered such that the signal and ground pins get reversed, and that of course will cause the device it is installed on to fail dramatically.However, there is another side to the story, another aspect that I dont think we considered yet.That is, these parts, used with automatic insertion machinery, will be loaded into the machinery via a tape reel. The tape reel SHOULD have the parts orientated in the SAME way as they were originally with the notch on the opposite corner, the way they were originally made. Thus, when the machine places them on the board, they should be orientated correctly even though the notch will be on the completely opposite corner. That means that the part should function normally.It could still fail a visual inspection though because the notch will be in a different place, so that would still have to be taken into account. It is hoped that there is a second way to verify the orientation rather than relying on the notch.I hope someone could verify this I can't do it right now. You may have to compare reels or something, or maybe a drawing showing the parts placement on the reel itself. On the new reel, the notch should be rotated by 180 degrees from the old reel.I still agree that the part number should have been changed but maybe if the new reel has the signal and ground pins orientated the same as with the old part, then the parts at least should load onto the PC board correctly. That is of course if this new information is true.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: August 17, 2023, 07:31:22 pm
content: So, say the PCB assemblers loads the tape reel in such a way that the pick-and-place machine places the component in a certain way, say like the way you mentioned with the notch on the opposite corner. Thus, the machine when placed would orient them correctly UNLESS the assembly notes otherwise.Without knowing of the change, that could be what happened in my case. Could the issue have been avoided if I worded the notes differently?I was basing my placement of the component on the notched side having pin 1. So, I asked to follow the silkscreen in terms of component orientation (i.e., notch silkscreen corner matches with notch on component). However, if I worded it to say that the notched side of the silkscreen outline is the side that pin 1 should be connected on, would the assembler understand that and place the component correctly based on how the part is loaded?

author: mikerj
author_rank: Super Contributor
timestamp: August 17, 2023, 07:50:25 pm
content: Quote from: MrAl on August 12, 2023, 10:55:34 amI did mention this in my first post in the thread...

author: MrAl
author_rank: Super Contributor
timestamp: August 18, 2023, 02:52:24 pm
content: Quote from: mikerj on August 17, 2023, 07:50:25 pmHi,Ok great, but I did mention that someone needs to verify that what I said was true, about the orientation being right if the tape has all the parts rotated 180 degrees from what they used to be, which would place the signal pin and ground pin in the right position even if the notch is not in the right position. I did not verify that was actually true yet.

author: RossJ
author_rank: Newbie
timestamp: August 19, 2024, 04:27:30 am
content: Quote from: MrAl on August 08, 2023, 11:53:12 amNot just a possibility... We purchased this part in late 2022 and used them in production. We noted at the time that the silk screen image (from the KiCad library) was wrong. As it turns out, these were the updated parts and the KiCad library was designed for the original part.We recently did a second production run using a different batch of connectors purchased during 2023. These turned out to be the older (pre-change) connectors! To make things more confusing, the remainder of the first batch was used before changing to the new batch. This led to a test panel being populated with different parts to those used in the rest of the run! Fortunately (as pointed out elsewhere in this thread) for us, dumb pick and place machines will get it right so long as the operator doesn't try to correct anything.Obviously the position of the signal pin can be determined by inspecting the bottom of the part. However, a queue when viewed after soldering is where the join in the ring is located. It is always (old or new type) above the signal pin. This is likely non-normative though.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 19, 2024, 07:39:27 am
content: More years ago than I want to believe, the TV station I worked at designed a device to, on a programme fail into the transmitter site, automatically switch the transmitter inputs to a local video source & to start a cartridge tape player for a spoken announcement.The video stuff required it to switch on&off, but the tape cart would run to its end, then re-cue by itself, which wasn't a major problem.We later replaced the cart machine with a compact disc player so had to modify the on & off functions.In the process, for some reason, (maybe because it was done in wire wrap) I removed a couple of NS monostable ICs which were used elsewhere in the box, & promptly lost one.After tearing the place apart, I gave up & grabbed one of the same number from the store.To my consternation, when I went to test the device, one of the monos timed out early & everything ceased.I could swap in the one original one I had (which was from a different function) & restore operation , but the fault then swapped with the IC.I tried every IC of that type in the store to no avail, pored over the National Semiconductors & Philips handbooks eventually finding a "throwaway remark" that some customers using the mono for short delays were having problems.National then fixed their problem by optimising the mono for short delays, rendering it useless for long ones, with Philips following suit.All good, but did they give the new design a different number?---Hell, No!, They kept the old number for the new design & changed the number for the old one.To us it wasn't much of a problem, as the device was an "In house" design, we just had to slot in a couple of the new number ICs, change the documrntation & it was all good, but what about a manufacturer with thousands of units "out in the wild"?