Hello ; Thank you for posting your request here and for the time taken to write to us. Regarding your description "I check the part inventory at LCSC Electronics and place it.." let us explain first that LCSC doesn't assemble parts because it is a company selling electronic components and it has its own stocks, the company which assemble SMT is JLCPCB and it uses its produced PCB and its own SMT Parts, means that JLCPCB has its own parts stocks that you can find through the following link : [https://jlcpcb.com/parts](https://jlcpcb.com/parts) Both LCSC and JLCPCB are sister companies, JLCPCB buy parts from LCSC to re-load JLCPCB stocks and both companies have their separated logistics process because they are not sharing the same stocks, the thing that these two companies share is the parts references and parts details, means the searching method in LCSC by reference is the same at JLCPCB. Backing to EasyEDA library, in the searching library please select "JLCPCB Assembled" class to get the supported parts by JLCPCB SMT Assembly. Here is a detailed explanation about how to properly get SMT Assembly by JLCPCB for boards designed under EasyEDA tool : [https://jlcpcb.com/easyeda](https://jlcpcb.com/easyeda) Considering your posted screen-shot, the two first parts are available in JLCPCB SMT parts library but the rest of parts are not available, it could be available at LCSC stocks but as I already explained above, JLCPCB can only assemble parts available at JLCPCB SMT parts library. Any further questions, just let us know. Thank you.

Thank you, support. It was very helpful. I understand that "LCSC only sells parts, and SMT assembly is impossible even if there is stock. JLCPCB does SMT assembly of parts in stock." Is it right? Among the components that go into the PCB that I make, many are not in JLCPCB. LCSC has all the parts I want. I think it would be great if LCSC parts could also perform SMT. In addition, are there any tips for finding parts for SMT? For example, I want to assemble DC005-2.0MM with SMT, but SMT is not possible, so I need to replace it with other parts capable of SMT. Is there a good way to find parts with similar performance and function? Is there just to study and experience a lot of circuits?

@SungukPark The DC Barrel jack that your are asking for has an SMD version that already exists on LCSC stock (see Ref. C319134) this is in case you want to have it as SMD part so you can just search for it at EasyEDA library by it LCSC Ref as it shows the below image  This is not supported by JLCPCB Assembly because JLCPCB hasn't added connectors to its Parts library and technically JLCPCB don't assemble any type of connectors, unfortunately for JLCPCB but the SMT process team are working in improving the service so hopefully it gets to exist in near future. About how to find the appropriate part support by the assembly service, no time wasting by checking the SMT Parts library to verify the part availability and copy its Ref and search for it in EasyEDA library, the simplest way is directly search for the part in EasyEDA library under "JLCPCB Assembly" class and you can check the availability for SMT Assembly as it shows the below image  Once you set some search key words related to your needed part, set"JLCPCB Assembly" classes and you will have the parts stocked at JLCPCB stock (even the parts that stocked before and have currently zero stock), the example above is for a resistor part and as you see in the red rectangle that is the stock at LCSC and in the blue rectangle that is the stock at JLCPCB means you can get it for SMT Assembly because it is available at JLCPCB stock :) If a part has zero stock at JLCPCB stock but it is available at LCSC doesn't mean that we can immediately order it for SMT assembly because our logistics has their re-load planing for each part. Hopefully that this helps. Anything else, just let us know ^_^

Hi, Support. Thank you for your kind explanation. It has been a lot of study. Parts that cannot be assembled by SMT will be purchased from LCSC. In this case, is there any way to order parts that cannot be SMT while purchasing PCB from JLCPCB? Do I have to place an order from LCSC? I mean that "while ordering PCB from JLCPCB, I want to purchase necessary parts from JLCPCB at once." If this is not possible, I will need to purchase parts from lcsc. In this case, I have to pay the logistics cost again, and I will be burdened. I am wondering if there is a way to get it shipped together.

@SungukPark As I mentioned in my previous comment, the JLCPCB company has its own logistic service and it is separated of LCSC logistic so unfortunately you can't combine one order for PCB from JLCPCB and parts from LCSC. Yes the missed parts you have to order them separately. Anything else, just post a comment here :) Glad to assist you.

Good afternoon, Support. Thank you for always replying. It's a natural part for PCB experts, but I'm a beginner so I'm curious about everything. One more question.  Here are some pictures of the PCB I made. Take the circled R1, for example. R1 is 10K and is LCSC Part No.C131361.However, I order the PCB from JLCPCB and there is no C131361 for SMT parts. So, I want to change it to another 10K resistor as shown in the picture below.  If you look at the 10K resistor replacements here, each has a different size. If I choose any of these as a replacement, they may differ from the size of my R1 PCB. In this case, SMT process would not be possible. Should I find a 10K resistor that matches the size of the R1 PCB I made and select it as a replacement? Or does the SMT proceed by modifying the PCB in JLCPCB even if I choose any replacement product? In addition, let's say I have to find it myself. Let's say I chose a 10K resistor that doesn't fit my size as a replacement. If I place an order in this state, will JLCPCB cancel the order after confirmation? Thank you.

@SungukPark Your main problem it that you manage to use JLCPCB Assembly service and you are searching parts at LCSC which is not convenient, so please search the parts availability at JLCPCB Parts library : [https://jlcpcb.com/parts](https://jlcpcb.com/parts) Regarding the example of the resistor, the following image is a screen-shot from our JLCPCB Parts library  In the search toolbar write the part description (see the black rectangle) You will find many parts having the same value but they have different package size (see red rectangle) your resistor has a 0402 package so the C25744 is the appropriate one as replacement since it is available in JLCPCB stock (see blue rectangle). One tip to consider is try to search for basic parts (see yellow rectangle) this will reduce the Assembly fees, find more details about this here : [https://support.jlcpcb.com/article/83-smt-assembly-faqs](https://support.jlcpcb.com/article/83-smt-assembly-faqs) One more thing, it is not about professionals or beginners, JLCPCB made it easy for any one to create a PCB and assemble it, the easy way. So we are here to reply to your questions whatever it is, so just don't worry about it :) Welcome.

 Hello! Something goes wrong - but today I can't find something in "JLCPCB Assembled" library: trying to fing 10kohm, stm32f030, sp485 - and get nothing

@egor121 Yes there is a problem in EasyEDA search library since yesterday, it will get solved soon so you can search again once this get solved. @[UserSupport](https://easyeda.com/UserSupport)

Thank you Support always. If I don't know anything about PCB, I will ask you. Thank you again

@SungukPark Problem solved, you can search in the EasyEDA library now :)

Hi, Support. I have made one PCB order at JLCPCB. When proceeding, I remember that there is a function to produce if there is no problem after reviewing. 1\. If there is something wrong\, will I notify you by email? Can you tell me what's wrong with it? 2\. Do you review the function I intended? I don't know much about the circuit, so I find SMT as a possible alternative, but I think it may not work as intended. I am wondering if there is a function to help verify the circuit. I will attach my circuit photo and BOM. I made a step down converter. My intention is "Input voltage Max 40V, and output voltage is adjusted by turning a variable resistor."  

@SungukPark Hello; We only review the design to check if it respects our capabilities or not but we don't check the circuit functionality itself, and this feature is not available among our services because we are a PCB manufacturer so we only provide PCB related services. But you can start a new topic in the forum under "**General Discussion**" and you can ask for help :) Thank you and good luck.

Hi! I suggest adding 100nF ceramic capacitor into the input and to the output. This should help with the ripple voltage in the output. Using only electrolytic capacitor in the input and the output may cause regulator instability in certain loads. Regards, Markus Virtanen HW / Electronics Designer