More bad parts from China - Page 1
Forum section: electronics / general

author: xrunner
author_rank: Super Contributor
timestamp: February 13, 2017, 12:20:44 am
content: This time right angle BNC adapters. I noticed noisy readings on a freq. counter and traced it to these BNC adapters. Attached are two pics - BNC Bad and BNC Good (for reference). The bad BNC is not made properly in that the grounding ring right around the insulator is supposed to have spring action slots cut in it so each part can spring out and touch the female BNC. The bad one has NO cuts in it meaning that it will not spring out and properly ground against the female. Beware before you buy these off Ebay (or anywhere) - look closely at the pictures before you buy!

author: avrishuvorlaz
author_rank: Regular Contributor
timestamp: February 13, 2017, 01:01:21 am
content: Simple solution: don't buy from China.

author: xrunner
author_rank: Super Contributor
timestamp: February 13, 2017, 01:05:03 am
content: Quote from: avrishuvorlaz on February 13, 2017, 01:01:21 amHow do I not buy parts from China when all these types of parts are made there as far as I know.

author: John B
author_rank: Frequent Contributor
timestamp: February 13, 2017, 01:13:13 am
content: Quote from: avrishuvorlaz on February 13, 2017, 01:01:21 amGood luck never getting anything from China!Thankfully, getting single/small number of items posted is still quite cost effective, so you can buy a sample to inspect the construction and quality before getting larger quantities.Thanks for the heads up OP.

author: trophosphere
author_rank: Frequent Contributor
timestamp: February 13, 2017, 01:24:28 am
content: We have to purchase from reputable re-sellers to decrease the chance of getting bad parts from China. That way, if they don't work as advertised then there is some sane way to get the money back.The majority of Chinese manufacturers aren't trying to purposefully screw the consumer*. They just want to cut costs and if they have to do less tooling then that is more money saved. The problem with their cost cutting measures is that they don't necessarily know the consequences and thus things they do - which may seem innocuous to them - result in poor function/dangerous consequences of the product they are manufacturing. It is the overall mantra to cut costs because everyone wants to make a buck and then some. The manufacturers that try to be more prudent about the decisions they make suffer as they have limited ways to cut costs in comparison to others and thus are priced out of the market. Consumers, in the end, look at the price tag of two competing products and if they seem similar on the surface then they go with the cheaper one. It isn't until they get bitten in the ass is when they start thinking and even then only a small portion do down the line.Which brings a good pearl of wisdom when having your product manufactured in China: One should always make frequent visits to ensure that the components/steps required to purpose a product to your design specifications is being met. The majority of manufacturers will try to make changes to save more money for themselves without telling you, and if you don't notice the changes then no one is the wiser. You have to keep them in line.* Some changes are just downright stupid and a malicious intent may be the most likely cause such as that melamine incident in baby formula to increase apparent protein content during tests.

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 13, 2017, 01:32:11 am
content: Quote from: avrishuvorlaz on February 13, 2017, 01:01:21 amYeah ...

author: james_s
author_rank: Super Contributor
timestamp: February 13, 2017, 02:39:14 am
content: The thing that gets me is that sometimes I'll buy something and it's actually very good, then later I buy another one and it's complete crap. You never really know what you're getting until it arrives so it's a crap shoot, however I've gotten a lot of really cool little modules and doodads. Often the total cost with shipping is less than just the postage would be to send it across town.

author: calexanian
author_rank: Super Contributor
timestamp: February 13, 2017, 02:46:28 am
content: +1 for buying from reputable companies. In connectors brand name still counts for something.

author: Cubdriver
author_rank: Unknown
timestamp: February 13, 2017, 03:41:15 am
content: I've had good luck with stuff from Pomona Electronics. Not sure where they're manufactured, but they seem to spec them properly so they're made correctly and work.-Pat

author: calexanian
author_rank: Super Contributor
timestamp: February 13, 2017, 06:18:34 am
content: Quote from: Cubdriver on February 13, 2017, 03:41:15 am+1 for Pomona test leads and jumper clips. For just connectors though you want to stay with the big boys. AMP, Neutrik, Amphenol, etc.

author: neil t
author_rank: Regular Contributor
timestamp: February 13, 2017, 07:03:20 am
content: Buyer beware, I think in general we just have to be a bit picky, I've learnt over the years to scrutinize pictures of stuff on ebay and buy low quantity until I have the parts in hand and then if they test out okay and it's something I use often I will buy more of the same (doesn't always work but mostly). for hi quality purposes I generally stick to amphenol and the like. As far as not buying from china that's a little crazy since if I buy at our local electronics store (here in Oz) i'm often paying at least 4x the price for the same components.Some manufacturers in china are good some are not, it wouldn't be the first time I've thrown bulk chips away from a bad supplier, I also keep a record of good suppliers (ebay sellers) and bad ones.regards Neil

author: Cubdriver
author_rank: Unknown
timestamp: February 13, 2017, 07:12:55 am
content: Quote from: calexanian on February 13, 2017, 06:18:34 amAgreed connector-wise, but I was thinking more for the adapters - looks like he has a 90 degree BNC street elbow there. I've got a fair number of the Pomona BNC Tees and Wyes, and the BNC to twin banana adapters in various sexes and configurations, and they seem to be good quality parts.-Pat

author: tkuhmone
author_rank: Regular Contributor
timestamp: February 13, 2017, 09:08:22 am
content: Quote from: calexanian on February 13, 2017, 06:18:34 amsame here, started to obtain few measurement clips from Pomona. Quality seems to be fine there, need to also use it longer time to see how it is in a used condition. In addition to Pomona I have some clips from Hirschmann.I have had problems with "non-branded" cheap RF-adapters (even in the case those were bought locally). Those were UHF-BNC adapters series. Within series they did not match each other, mechanical tolerances were too big. I try to avoid non-branded RF-connectors...My last BNC T-adapters I have ordered as Amphenol brand. Those have not yet arrived, I expect them to be good quality.For RF connectors, I nowadays buy from well known brands. Couple of those were mentioned earlier - occasionally I use Suhner, Radiall & Rosenberger connectors & adapters.EDIT (2017.02.16): BNC T-adapters arrived (Amphenol). Quality is good and fit to scope is OK. Those BNC male connector, have six sections of outer conductor...

author: raspberrypi
author_rank: Frequent Contributor
timestamp: February 13, 2017, 07:47:14 pm
content: Are sure it was China? China is known for its exacting standards and quality craftmanship due to highly paid and skilled workers. You are probably thinking of switzerland or Germany. China has too many quality controls in place to allow such a thing.

author: Dielectric
author_rank: Regular Contributor
timestamp: February 13, 2017, 08:31:57 pm
content: Quote from: tkuhmone on February 13, 2017, 09:08:22 amI've seen Pomona test leads that were probably used by William Shockley himself. They only get better with ageAs opposed to some cheapy pincer leads I bought that don't even have enough spring in the clips to stay on a jumper wire, or the "grabber" J-hooks that just sort of straighten out.

author: mcinque
author_rank: Unknown
timestamp: February 13, 2017, 09:15:15 pm
content: It's not a matter of China made items. It's a matter of quality control and - consequently - price.Buy at cheap prices from an unnamed Shenzen reseller and you'll get what you pay for.Buy from a reputable brand thru official distributors and you'll get good items.I don't understand why whine about quality when buying at the lowest price. It's a risk you should know.

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 13, 2017, 09:44:25 pm
content: Quote from: mcinque on February 13, 2017, 09:15:15 pmSo, as in reversal, if you buy everytime at the highest price, you'll get everything the best?No, belive me, that`s a to short thinking, both is wrong.The price has absolutly nothing todo with quality. You only have a better chance, that's right.But, there is no ohms law in this manner.

author: raspberrypi
author_rank: Frequent Contributor
timestamp: February 13, 2017, 10:08:05 pm
content: Quote from: mcinque on February 13, 2017, 09:15:15 pmIn America you dont often have a choice. EVERYTHING is made in China and often its sold at a huge mark up. Its normal to see household items in a store that cost a fraction of a cent to make from China for $20 or $30USD. 15 years ago you could spend more and get a better one or less for the chinese one but not anymore. Spend more and you still get the chinese one. Then these companies bitch that wages are too high and they pay too much in taxes. Its disgusting and alot of people are sick of it but they blame the wrong people, they think people like Trump will fix it when they in fact are the main offenders.

author: mcinque
author_rank: Unknown
timestamp: February 14, 2017, 12:33:58 pm
content: Quote from: hwj-d on February 13, 2017, 09:44:25 pmof course not. Overpricing a product doesn't change anything.Take Peaktech for example: rebranded product at highest prices.I mean if that you want a good connector and you'll buy from a valuable manufacturer, you will have a good product.Quote from: hwj-d on February 13, 2017, 09:44:25 pmIf you want to produce a well engineered, valued item and do proper QA, you will have costs. This is no short thinking, is a reality. While the price itself doesn't mean that a product is good, underpricing will warn you about the opposite.A good BNC connector for example, with proper heat resistant insulation and a good nickel plating of the outside and good gold plating of the center pin, assembled on a line that do proper QA control, cannot be sold at 0.15$ and do profit on it.

author: mcinque
author_rank: Unknown
timestamp: February 14, 2017, 12:39:28 pm
content: Quote from: raspberrypi on February 13, 2017, 10:08:05 pmI think it's the same in EU. But look at iPhones: made in China but well made.I mean that the matter is not China. If you're looking for good connectors, why you can't buy "TE Connectivity" products from RS, Digikey or Mouser?

author: saturation
author_rank: Super Contributor
timestamp: February 14, 2017, 02:12:23 pm
content: Thanks for the very good photos. Even if they were dimensionally perfect on visual inspection and seemed to fit well, we've found no-brand connectors, BNC or otherwise, can perform poorly. Reflections and frequency response vary. We keep some just to demo how bad they can be. Granted we use them only for <= 500 MHz, quality BNC is rated at least to 2 GHz.The cheapest connectors we use by brand is Amphenol RF. You'd have to buy them only from reputable dealers and the price is very reasonable. Last I checked, they are Taiwanese in origin. Also Jameco Valuepro BNC connectors are good to at least 500 MHz, also Taiwanese origin. Its not so much the country as the willingness of the maker to provide a product to spec, then price it later.The US version does not show country of origin, i.e., Newark, the UK and other EU site versions do.http://uk.farnell.com/amphenol-rf/31-9-rfx/adaptor-bnc-jack-bnc-plug-50ohm/dp/1704390?ost=31-9-RFX&selectedCategoryId=&categoryNameResp=All%2BCategories&searchView=table&iscrfnonsku=false

author: xrunner
author_rank: Super Contributor
timestamp: February 14, 2017, 03:06:20 pm
content: Quote from: saturation on February 14, 2017, 02:12:23 pmQuoteYou're right, that's a reasonable price and I should buy those. You know another issue with these cheap BNC's I've noticed on several pre-made cables and adapters is that they simply can not be inserted onto other BNCs all the way. I've inspected them up close and it's not obvious what the problem is. I think it's a matter of a few thousanths of a inch in tolerance inside but I can't tell. I just have to throw them away because you cannot repair them.

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 14, 2017, 03:28:17 pm
content: Quote from: mcinque on February 14, 2017, 12:33:58 pmYes. I'm by you. But this is our subjective, pardon, "feeling" from the viewpoint of them who manufactures the goods. But, not only, these chinese products are often very cheap and nevertheless pretty good. Why? There is the world of traders and politics, which determine the price, at first to be the cheapest on the market, after that and out of competition, to be the highest for max profit. As you can see, there is no general linear dependence as it should be from customers perspective. Maybe that's the point where poverty comes in, if we think e.g. about food speculation.And therefore we should develop a certain competence for what we will buy, that's right, but in both directions.Edit: This BNC-connectors are big crap, without question. The seller knows...

author: jfasoc
author_rank: Contributor
timestamp: February 16, 2017, 12:08:28 pm
content: A lot of good stuff is made in China, but they also make a lot of things that will kill you if you look at it wrong.If you are lucky you can get good things at less than 1/10 the price from Shenzhen but you never really know what it is you got. When you receive it you can see if it looks good. You take it apart you can see if it looks well made.What bugs me about things bought directly from Shenzhen is that you never really know how it was made, what it is made of. It looks OK, but what kind of plastic is that, what is in it, is that really copper, is that really stainless steel.

author: mcinque
author_rank: Unknown
timestamp: February 16, 2017, 01:01:24 pm
content: Exactly.If you buy from a known and respectable manufacturer or from one of its distributors, you know that you will get the same quality items for each order you place. If you buy connectors from TE connectivity, you will get the same connectors at every restock.Instead, if you purchase from an unknown (or even known) chinese reseller, you can't know where he get his stock; probably he purchase at the best price he can find, so changing its source every time. When you order from sellers like this, you can't know what you get until it arives. And if one time you got good items, the next time will be different probably.

author: testian
author_rank: Regular Contributor
timestamp: February 16, 2017, 01:20:48 pm
content: Often spare parts which does not fit the manufacturer requirements are sold on ebay for cheap. I usually buy things from aliexpress they have a quite good buyer protection.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: February 16, 2017, 03:07:05 pm
content: The worst culperts seem to be Chinese capacitors. I got a batch that looked good until you looked at the bottom. They all had different design patterns, dirty and some looked broken. They obviously tried to cover up the poor quality by using clean new plastic wrappers.

author: Codebird
author_rank: Regular Contributor
timestamp: February 16, 2017, 03:26:40 pm
content: After an encounter with some 'not-ky diodes' (regular small-signal diodes with a fake label) I've started building an instrument with the express function of measuring components under various conditions to identify counterfeits and defectives. In an amusing irony, all the parts are ordered off of eBay. From China.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 16, 2017, 03:46:15 pm
content: Buying from known brands does not assure quality, it only makes it more likely. The big guys are also competing for your dollars and the low price guys are taking their business. Some of them will naturally slip down a bit on the quality side to compete. If you could plot quality vs price for all the online retailers and all the distributors and manufacturers the correlation coefficient would be non zero and positive, but you would find not a simple line but a very fuzzy cloud. If you did the same thing over time you would see the same fuzziness, but the points would be moving around, mostly down and to the left.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: February 16, 2017, 03:49:41 pm
content: The killer for me is unknown spec parts which are rife.For example if I buy a 1k 0.25W MF resistor from China, what am I getting? Fuck knows.If I buy a 1K 0.6W MF resistor from RS from TE Connectivity (LR1F series), I'm getting a known 50ppm/oC, over twice the power dissipation in the same package footprint and it'll be delivered by courier the next day for a total of £0.46!A while ago I had some Chinese MF resistors which were more thermistors. I was wondering why the gain on my amp was shifting slowly and it turned out that the 1k resistor in the feedback network had drifted down to 811 ohms.

author: mcinque
author_rank: Unknown
timestamp: February 16, 2017, 08:42:56 pm
content: Quote from: CatalinaWOW on February 16, 2017, 03:46:15 pmIt depends. Just for example: buy Panasonic or Nippon Chemicon electrolytics. Buy Vishay resistors. Buy Murata caps. Buy Noble or Bourns potentiometers. Quality is assured. There are companies that sells quality products.You can bet that if you buy from a reliable connector manufacturer, you'll get the same connectors quality if you place an order every 6 months.I said "you will get the same quality items for each order you place", while on chinese "no-brand" market you'll get probably different stocks every time you purchase.

author: james_s
author_rank: Super Contributor
timestamp: February 16, 2017, 10:58:33 pm
content: The only poor quality resistors I've ever encountered were generic dirt cheap Chinese stuff. Anything from any sort of recognizable brand ought to be decent, it doesn't have to be top notch stuff.