[Letters from Customers] 100% E-test, necessary or not?

It’s Friday again, at least in China! Friday is coming all the way, and it’s time for me to discuss a topic with your guys which I selected from letters from customers. This week, a customer brushed up against a problem on PCB, and after he fixed it he wants us to post the whole thing as a reminder for other customers who would like to take advantage of this service. Thanks a lot! We appreciate your warm heart very much! Then following is the story.

You know we offer fusion PCB service, but have you noticed that one of the options you need to confirm is the type of E-test? E-test is an optional service we provide in the case that you need to make sure all boards are ok, without electrical problems once you get the package. And for this item, 50% E-test and 100% E-test are two available options. That means you can have your boards half pretested or all pretested. We advise you to choose the latter one to assure your satisfaction, but considering even if there are some flaws they tend to be easy to be fixed yourself, so you can choose 50% E-test to save the cost.

Usually problems with the untested part are some kinds like extra metal, but this time our customer find a new problem:

“…However, on the third PCB, I found this shown in the yellow circle on the attached image file.  I have never seen this before on the PCBs.The traces just don’t connect.  It is very obvious….

Here is the attached image:


This is an infrequent situation. Our customer found his way to solve this problem like this:

“I added wires to my board to replace the 3 traces that were bad. After doing this, the board worked properly.”

And he suggested that we should share his story at the end.

First of all, we are sorry to hear about this problem, because it may cost you a while to deal with it. And then we need to make it clear that 50% E-test means some degree of risk. Of course, we are always ready to help you solve those problems, but if your total amount is getting high enough, then 100% E-test is strongly recommended. After all, it cost you only $10 more no matter how many boards you need to be tested.

However, if $10 occupies a fairly big proportion, then 50% E-test may be your better choice. Don’t worry about those problems, because our after-sale team is ready to give you support all the time. If there is any problem, send us a letter! We will try our best to fix it. And guess what, on the other side, you have a community to support you like the warm-heart customer we mentioned above. So that’s it! See you next week, or I should say “Have a nice weekend!”

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6 thoughts on “[Letters from Customers] 100% E-test, necessary or not?

  1. I just noticed that you had posted about my issue. I appreciate that you are informing customers in this way.

    In the future I will probably order 100% eTest on any orders of more than 10 PCBs.

    If I am only prototyping something, I would probably order 10 PCBs with 50% eTest. This is what I would recommend to others.

    By the way, I posted about this at DangerousPrototypes, also. If you care to read a bit more on the topic, it’s here.

  2. Boards that have been tested have two red or black lines on one wall side. That’s the mark you can use to tell tested ones from untested ones.As to failing boards, if a slight modification can fix them (like remove extra metal) , they will be fixed. If not, they are usually trashed by our supplier, instead of being passed to us, not to mention passed to customers.


    What happens when you run across a board that does not pass the E-test? Is it trashed or is it shipped to the customer? Is the customer somehow notified that the specific board did not pass?

  3. What happens when you run across a board that does not pass the E-test? Is it trashed or is it shipped to the customer? Is the customer somehow notified that the specific board did not pass?

  4. We usually use Flying Probe Test as a main E-test tool. With that tech, we check for shorts, broken circiuts, and poor connections all over a PCB board.It’s used to make sure each component performs as expected. Not simply check for shorts between all nets, but follow a pre-programmed application to make sure all components are set right and read right on a multimeter.

    Steve Marple:

    Can you tell us exactly what gets tested and how? I imagine you test all pads on a net conduct? And then repeat that for all the nets? Do you check for shorts between all nets, or just ‘neighbouring’ nets?

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November 2011