Buying the wrong part - even after you tried to tell them - Page 1
Forum section: electronics / general

author: Brumby
author_rank: Unknown
timestamp: February 25, 2016, 11:27:43 pm
content: Many years ago, I was chatting with the manager of a Jaycar store, when a guy came in asking for a part. He described a standard DIP package and did not seem to understand he needed to provide a specific number. He didn't know if it was 14 pin or 16 pin, what it did or where in a circuit it went - he just wanted one!To try to illustrate the variety of different ICs, the manager turned to the wall of drawers behind the counter and grabbed one at random. Before he could utter a word, the guy just about jumped out of his skin "YES! That's It!!!"After that, nothing - and I mean absolutely NOTHING - that either of us said to him would get him to evenconsiderit was the wrong part. He just reached for his wallet and insisted on paying for it and after some further words of warning, he completed the payment and left the store.The manager and I just looked at each other.There were no words.

author: XOIIO
author_rank: Super Contributor
timestamp: February 25, 2016, 11:33:30 pm
content: Ever hear back from him? I want to know the ending!

author: Brumby
author_rank: Unknown
timestamp: February 25, 2016, 11:42:00 pm
content: I asked the manager that very question several months later ....He never showed up again and nothing was heard from head office nor any other sources.Maybe he got the right part?

author: MapleLeaf
author_rank: Contributor
timestamp: February 26, 2016, 01:27:05 am
content: Or maybe he needed one as a "show and tell" and not as one to install.

author: Stonent
author_rank: Super Contributor
timestamp: February 26, 2016, 01:42:42 am
content: The common wrong part I'm asked for in IT is a "splitter cable".Sometimes people will just come by and say "Do you have any splitter cables?"And never say what they want to split without us prompting for clarification. Frequently they will be very evasive and many times just continually ask for the item thinking they know better than we do.So recently when someone asked for one I said "First, tell me what you're trying to split and then I'll tell you how it probably won't be what you really want."So far I've had:1. Ethernet splitter so they could run 2 computers from 1 port just like how you can run two analog phones off one one RJ11 port with just some wall plug. This one I told them "ethernet doesn't work that way, you need to put in a request for a second port to be installed" as I was leaving I heard the guy make a remark "Don't bother with that guy, you just need a splitter cable, that's all."2. VGA Splitter cable. Now this one I try steer them away from because yes it will "work" but it tends to cause both displays to be darker or blurry. They also seem to think that simply splitting a VGA cable gives them the capability of independent displays. Since we use Dell computers, they pretty much all have a vga port and 1 or 2 digital outputs as well, so we can usually accomplish what they want to with a Displayport or DVI cable.3. HDMI Splitter cable. They wanted to run TV screens that were fairly far apart from one port. I told them something like that would probably not work because HDMI is digital putting the extra load on the signal would probably cause neither to work. We do have and have used devices from Extron that are powered multiport signal boosters that work well, but they typically want something cheap, and these tend to not be.Another one is wanting some sort of USB gender changer so you can connect A to A or B to B.

author: Leiothrix
author_rank: Regular Contributor
timestamp: February 26, 2016, 02:32:43 am
content: Quote from: Stonent on February 26, 2016, 01:42:42 amBeing really picky, but 10/100 Ethernet only requires two pairs, so you can run two separate connections from one cable. The two connections have to be wired in at the switch for it to work though obviously.Just pointing out that maybe they actually had seen something like that before, they wouldn't know how it worked. Or why doing it like that is not particularly recommended, but anyway.

author: Brumby
author_rank: Unknown
timestamp: February 26, 2016, 04:06:44 am
content: I think you're being overly generous.An RJ45 just looks like a fat RJ11/RJ12 - and theyKNOWhowtheywork, so the wider one will work the same, won't it?!!

author: Halvmand
author_rank: Regular Contributor
timestamp: February 27, 2016, 07:30:20 pm
content: My local electronics stores owner is of that type. One of the first times I where there I was after some filter capacitors. I only knew the value I needed.He of course grabbed the most expensive without asking further questions. And I walked out the store without capacitors but with a bad taste in my mouth. Hated him ever since.Another time and in another store I asked the cashier for a to-220.He though was nice enough to tell me that to-220 was the packet style.Sadly ELFA does not have physical stores in denmark any more, yet the idiot with his overpriced components and horrible costumer service is still there.

author: nctnico
author_rank: Super Contributor
timestamp: February 27, 2016, 07:37:42 pm
content: Quote from: Stonent on February 26, 2016, 01:42:42 amThese do exist to transfer files from one computer to the other.

author: wraper
author_rank: Unknown
timestamp: February 27, 2016, 07:40:37 pm
content: Quote from: Leiothrix on February 26, 2016, 02:32:43 amThat is not splitting and certainly isn't something that average clueless guy would want. This is only an option when you have a one cable (for example, in the wall) but need two Ethernet connections.

author: Stonent
author_rank: Super Contributor
timestamp: February 27, 2016, 11:41:55 pm
content: Quote from: Leiothrix on February 26, 2016, 02:32:43 amYeah but in our case that had already been done at that time. One of the previous guys here liked to cheat and use one cable for 2 ports in the wall. That caused a problem last year when we got rid of all the remaining analog phones and the split cables could not support the power over ethernet on the voip phones.

author: jwm_
author_rank: Frequent Contributor
timestamp: February 28, 2016, 12:04:25 am
content: Apparently these fire hazards are asked for enough that ACE hardware made a sign about them.https://consumermediallc.files.wordpress.com/2009/01/aceadapter.jpg?w=640&h=746

author: JoeN
author_rank: Frequent Contributor
timestamp: February 28, 2016, 12:44:48 am
content: Quote from: Halvmand on February 27, 2016, 07:30:20 pmThen he misled you. It's the package style.

author: GabYoung92
author_rank: Regular Contributor
timestamp: February 28, 2016, 01:28:53 am
content: Quote from: Stonent on February 26, 2016, 01:42:42 am"I've seen it on eBay!" ...

author: Brumby
author_rank: Unknown
timestamp: February 28, 2016, 11:54:29 pm
content: I actually purchased a cheap HDMI splitter to parallel one of my computer monitors to a bigger screen TV when required. I thought that by having the same native resolution, I would at least be starting off with half a chance. My monitor connection is essentially buried, with the TV being a little more accessible.The bottom line is - it workedBUT....For my graphics card to deliver the right signal at boot up or changinganydisplay settings, the TV had to be completely unpowered - not in standby mode - or have the HDMI plug removed.In addition, every now and then (from 0 to 4 times a day) my monitor would black out for a couple of seconds before returning to normal. This would happen even if the TV HDMI cable was completely removed.I decided my need was not enough to put up with this, so it's now sitting in a box somewhere.

author: Galenbo
author_rank: Super Contributor
timestamp: February 29, 2016, 08:17:06 am
content: Quote from: Stonent on February 26, 2016, 01:42:42 amJust sell them what they ask. They've done the research, they defined the specs, they take responsability.Let them make notes of their specs, you know, for "educational" purposes.Next time, if they come again, they will first ask for consulting and advice.I saw a guy enter a store, asking for "a working round fuse"For him, "working" was defined as the device make sound again and don't stop.Well, the shop salesguy sold him the fuse with the highest value, this gave the best propability for "working"

author: Artlav
author_rank: Frequent Contributor
timestamp: February 29, 2016, 08:26:46 am
content: Quote from: jwm_ on February 28, 2016, 12:04:25 amWTF?Can someone explain why would anyone need something like that?I tried googling, and christmas lights come up a lot for some reason, but i don't get what the use case is.

author: Artlav
author_rank: Frequent Contributor
timestamp: February 29, 2016, 08:32:11 am
content: Quote from: Artlav on February 29, 2016, 08:26:46 amAh, ok.Apparently christmas lights commonly come with a female socket on the opposite end of the string, for ease of wiring.That makes sense, kinda.

author: XOIIO
author_rank: Super Contributor
timestamp: February 29, 2016, 10:32:28 am
content: They are actually most commonly used for backup generators. If the grid goes down, power up the genny, plug into it, and plug into an outlet in the house, and you have power again.They are called suicide cables.

author: Jeroen3
author_rank: Super Contributor
timestamp: February 29, 2016, 02:16:18 pm
content: Him: "Can you give me an DVI - VGA adapter?"Me: "I can, but it won't work on your dock".Him: "Sure it does, it works at my home pc".Me: "Yes, but there are different versions of DVI. It actually needs more pins for the vga signal".Him: "I'll buy one myself!".I should have given him one on a bet for a crate of beer if it didn't work.

author: stmdude
author_rank: Frequent Contributor
timestamp: February 29, 2016, 07:53:24 pm
content: Quote from: Jeroen3 on February 29, 2016, 02:16:18 pmOh, crap. That's the bane of my existence at work right now. Apparently, I'm the only one in a building of engineers that knows the signaling in DVI, HDMI and DisplayPort.. Things got a lot worse after we started buying 2560x1440 monitors.IT Guy: "I bought a bunch of mini-DP to DVI converters (cheap), but they won't give full resolution"Me: "Are they dual-link?"IT Guy: "Huh?"Few days later:IT Guy: "So, I figured out that the laptops have HDMI, as do the monitors, so I bought a bunch of cheap HDMI cables"IT Guy: "But, the screens keep going black"Me: "Are they high-speed / HDMI v1.3+?"IT Guy: "That's all bullshit.. It's all digital, man.."Me: "It's _10Gbps_ digital..."

author: wblock
author_rank: Regular Contributor
timestamp: February 29, 2016, 08:15:19 pm
content: Related:http://www.newegg.com/Product/Product.aspx?Item=9SIA76H35K0295That is a DVI to VGA adapter. DVI-D, as in no analog pins in the connector. Call me skeptical about there being active D/A circuitry in a $4 adapter. But I would really like to take one of those apart and see if there is even an attempt.

author: hli
author_rank: Frequent Contributor
timestamp: March 01, 2016, 07:42:50 am
content: Quote from: Stonent on February 26, 2016, 01:42:42 amUSB port A to port A is sometimes needed. I got my hands on an external hard disk enclosure, and only realized afterwards that it just had an USB-A connector. I sacrificed two USB cable and soldered them together...

author: Zbig
author_rank: Frequent Contributor
timestamp: March 01, 2016, 08:16:12 am
content: Quote from: hli on March 01, 2016, 07:42:50 amIt was only needed because some moron designed the enclosure to have improper, standards-violating downstream USB A port in the first place. Probably it was cheaper than the proper one.

author: nogood
author_rank: Contributor
timestamp: March 01, 2016, 08:20:59 am
content: Quote from: Galenbo on February 29, 2016, 08:17:06 amYou contradict yourself a little bit there: First you say, if the customer has researched it and knows better (than you) what wrong part to buy, "just sell it" etc. . Then you bring up an example of an obviously non-informed customer, who doesn't know anything about fuses and may set his house on fire if you sell something like that to him.Quote from: hli on March 01, 2016, 07:42:50 amI blame that on cheap micro usb cables. Many people will tell you, that micro usb is crap because can pull the cable out of the device by looking at it funny. Interestingly I can relate, but this only happens with cheaply made (not always cheap) cables, which do not interlock correctly. Also sometimes the micro usb ports in the device is recessed too far to lock tight with thicker connectors.One may argue that micro usb is not as sturdy as USB-A, but that is what USB-B or by a stretch mini USB-B is for IMHO. Hardrive enclosures with USB-A are a big red flag not to buy that product for me.

author: XOIIO
author_rank: Super Contributor
timestamp: March 01, 2016, 08:24:06 am
content: Quote from: Zbig on March 01, 2016, 08:16:12 amI actually prefer USB A to A, it would be much nicer than the micro usb 3.0 connectors that are used more commonly. It just feels like a much more secure and strong connection.

author: karoru
author_rank: Regular Contributor
timestamp: March 01, 2016, 04:22:38 pm
content: Quote from: Brumby on February 26, 2016, 04:06:44 amI'm up for making some twisted pair Ethernet cable with RJ11 plug on one side. Why waste power for these blinkenlight router magic, when you can just connect your computerstraight to the landline! Special offer includes software DSL to Ethernet converter & if you buy it today you get free 3-month America Online subscription.

author: hli
author_rank: Frequent Contributor
timestamp: March 01, 2016, 09:09:02 pm
content: Quote from: Zbig on March 01, 2016, 08:16:12 amThats right, its non-standard and should not have been used. Now its a red flag to me as well, but back then I just did not think about it (and was expecting either a B or USB-Mini socket). But given the situation, what should I do? Throw it away?

author: Galenbo
author_rank: Super Contributor
timestamp: March 07, 2016, 02:53:33 pm
content: Quote from: nogood on March 01, 2016, 08:20:59 amLife is full of contradictions. And full of dangers.The customer wasn't non-informed, he was false-informed. I wasn't selling, I was the customer beside him.There was no way to stop him because everybody already saw the insults and false accusations coming.

author: Galenbo
author_rank: Super Contributor
timestamp: March 07, 2016, 02:56:59 pm
content: Quote from: Zbig on March 01, 2016, 08:16:12 amLike this moron:

author: wraper
author_rank: Unknown
timestamp: March 07, 2016, 03:44:46 pm
content: Quote from: XOIIO on March 01, 2016, 08:24:06 amThe micro USB connector itself is much more robust against the mechanical damage than USB A, and, especially, USB B which can be ripped off with a slightest mechanical abuse. The micro USB connector itself gets damaged very rarely. The question is, how they are mounted on the PCB, if it is just surface mount, they can be ripped off with the pads. But if they are soldered into 4 holes in the PCB, they are almost indestructible.

author: macboy
author_rank: Super Contributor
timestamp: March 07, 2016, 04:27:19 pm
content: Quote from: blueskull on March 01, 2016, 07:02:30 amIn what universe does it not? On every DVI, Pin 14 is +5 V and pin 15 is the return/GND for it. HDMI has this +5V also, and it is commonly used to power active repeater/equalized cables, VGA adapters, etc.

author: nogood
author_rank: Contributor
timestamp: March 07, 2016, 05:17:29 pm
content: Quote from: Galenbo on March 07, 2016, 02:53:33 pmWell I see a burned down house coming, that's why doing things this way is bad.I would not support a shop like this in any way.

author: wraper
author_rank: Unknown
timestamp: March 07, 2016, 05:27:35 pm
content: Quote from: macboy on March 07, 2016, 04:27:19 pmYes there is 5V, and you can buy a real active adapter cheaplyhttp://www.ebay.com/itm/121639927599or even cheaper HDMI adapter (which I bought and it is a real deal)http://www.ebay.co.uk/itm/131425635470. However that particular adapter is a non working BS which have approximately five wires in it IIRC.

author: jwm_
author_rank: Frequent Contributor
timestamp: March 08, 2016, 12:18:20 am
content: Quote from: Galenbo on March 07, 2016, 02:56:59 pmThat is the correct socket, that is a downstream port; it sources 5V. It is not to run the thing off 5V. (though, it will probably sorta work like that by accident if you don't care about 5V regulation)

author: rrinker
author_rank: Super Contributor
timestamp: March 08, 2016, 03:55:47 am
content: See, always learning something. I would have been with Galenbo on those, that it was designed to input 5V either via the USB port or the coax jack. I looked at the one I have sitting here and sure enough, the USB port is to OUTPUT 5V, not feed power in. Might be in the instructions, had I bothered to read them, or if it even came with any, I don't recall. I've just been using a small wall wart with a coax connector to power the supply which powers the breadboard.

author: Galenbo
author_rank: Super Contributor
timestamp: March 08, 2016, 07:59:13 am
content: Quote from: jwm_ on March 08, 2016, 12:18:20 amNo it is not. No need to make things up to make it fit.Nobody wants to charge a phone on this thing.http://www.aliexpress.com/item/1PC-Promotional-Breadboard-Power-Supply-Module-3-3V-5V-MB102-Solderless-Bread-Board-DIY-New-Power/1884561980.html"Input voltage: 6.5-12 V (DC) or USB power supply"

author: OilsFan
author_rank: Regular Contributor
timestamp: March 08, 2016, 08:36:49 am
content: Quote from: jwm_ on February 28, 2016, 12:04:25 amWe use things called cam-lok suicide pins at work all the time on generators and sound stage power cans. They are M/M or F/F as needed. You are only supposed to use them on reverse ground schemes when your cable or distribution boxes do not have the right connectors. You run reverse ground in order to prevent mixing it up with one of your phase legs, especially the blue phase leg as a lot of people can't see the difference between Green and Blue. This is especially true under bad lighting conditions like using a cheap blue led head lamp in a dark forest at 3am. You could easily hook the blue phase leg up to the ground making all of the metal chassis hot if ground were not reversed. Here is what they look like....http://www.filmtools.com/casuco.html

author: jfasoc
author_rank: Contributor
timestamp: March 08, 2016, 08:47:42 am
content: Quote from: Leiothrix on February 26, 2016, 02:32:43 amI have done that in my apartment. Easier than running another cable or putting up another switch. Works fine.