Experiences with returns / manufacturing defects with PCBWAY - Page 1
Forum section: electronics / general

author: MrD
author_rank: Contributor
timestamp: April 09, 2020, 06:01:49 am
content: Has anybody got any experience with returns to PCBWAY? I'd like some advice:I've used PCBWAY for the PCB fabrication and SMT assembly for two of myGame Raccoonboard revisions now.For my latest revision, I ordered two identical fully assembled prototype boards, both appeared to be high quality with good components. One of which works perfectly as far as I can tell, but I'm having an issue with the second. I have a Flash unit on the PCB, and in testing I found strange mirroring behaviour in the address space. I tracked it down to a short between two physically adjacent address lines. I believe it's due to a soldering error around the pads of one of the devices attached to my address bus (transceiver, microcontroller, Flash), but I can't see anything visually. I've tried cleaning the board gently with IPA but the two address lines are still showing low resistance under a multimeter.I think it's best that I send this back to the manufacturer as I'm certain this board wasn't manufactured properly. Does anybody have any experience sending non-working projects back to PCBWAY for a refund and could give me some advice? What information should I prepare before I contact them?

author: OwO
author_rank: Super Contributor
timestamp: April 09, 2020, 06:41:02 am
content: You've already found the short, so it should be easy to determine if it's a board or soldering issue. Remove one or both of the chips and check for a short again. PCB shorts just shouldn't come up at all (100% e-test is standard), so I would change suppliers if that is the case. Soldering defects otoh are normal and even in production you can have 1-2% units fail. If you ordered only 2 units of PCBA, it is going to be hand-placed or even hand-soldered and will have a higher defect rate. That's just the way it is and I would just fix it when it happens.

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: April 09, 2020, 06:42:19 am
content: No experience here, but suspect if you did a large order with a Chinese PCBA house (>500pcs) then you might have some push. But with a prototype run of two I would imagine they would at best give you a discount on the next order

author: OwO
author_rank: Super Contributor
timestamp: April 09, 2020, 06:48:38 am
content: I read your post wrong and thought you had already tried touching up the soldering at the shorted pins. Do that first. Apply some flux and drag a cleaned soldering iron across the pins.

author: MrD
author_rank: Contributor
timestamp: April 09, 2020, 10:14:26 am
content: Thank you both.I can't remove the chips myself - I have absolutely no experience with surface mount, and wouldn't want to wreck the board if I have to send it back to PCBWAY.https://imgur.com/a/P6wUCFMThe highlighted lines are the ones that are shorted together (these link to A15/A14 on the Flash and on my internal address bus). I can't see any fault in the soldering at the Flash at the top or at the 164245 transceiver at the bottom. Retouching wouldn't hurt, I'd just have to be very careful there.Looking at it again with the layout file in front of me, the pins are either side of one of the many ground pins on the 164245 so they might even be connected together through that - when I'm able, I need to test to see if they're both shorted to ground and each other there.

author: OwO
author_rank: Super Contributor
timestamp: April 09, 2020, 11:12:44 am
content: Is that a shitload of solder bridges on IC4?

author: MrD
author_rank: Contributor
timestamp: April 09, 2020, 11:22:29 am
content: They're unused transceiver inputs from the cartridge side being held to ground.

author: Pinkus
author_rank: Frequent Contributor
timestamp: April 09, 2020, 01:00:43 pm
content: Cut the PCB tracks one by one (of course only at places where they can be easily patched - usually at a pad or at a via is a good place) and measure again to narrow the problem down.Or if you own a thermal camera, let some current flow to find out, where the shortage is.

author: SMdude
author_rank: Frequent Contributor
timestamp: April 09, 2020, 01:08:56 pm
content: IC1 pins 25 and 26 appear to be shorted.

author: MrD
author_rank: Contributor
timestamp: April 09, 2020, 01:38:22 pm
content: Quote from: SMdude on April 09, 2020, 01:08:56 pmIntentional (and also shown on the design image). I'm holding the Flash's !CE on pin 26 low at all times by connecting it to the adjacent ground on pin 27 as I only need !WE and !OE control, this is a valid way to operate the Flash according to the datasheet, and works on the non-malfunctioning prototype board.

author: JDubU
author_rank: Frequent Contributor
timestamp: April 09, 2020, 02:09:37 pm
content: Have you tried heavy fluxing and reheating pins 1 and 2 of IC1?

author: jmelson
author_rank: Super Contributor
timestamp: April 09, 2020, 03:36:47 pm
content: There are 3 vias in a row, to the lower left of the square chip. The two affected lines pass very close to the leftmost of those vias, on the back of the board.There could be a short right next to that via. Might be worth a look with a powerful magnifier and good light.Jon

author: E-Design
author_rank: Regular Contributor
timestamp: April 09, 2020, 04:20:02 pm
content: To cycle back to the OP original question..That board doesnt look like it is pushing the processes of PCBway - so I would put the odds that your short was created during assembly and not built into the PCB.Ive done a lot of PCBWay boards, and never have had an issue. Sometimes if they find a small cosmetic defect, they will email me a picture and ask me if its ok.Great service experience from them - highly recommended.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: April 09, 2020, 09:57:27 pm
content: Top left of IC 1, you have a track running exceedingly close to the pad. I would move the bend in that track over.And it may just be the image or my monitor, but some of the pads for IC1, IC3,& IC4, seem to vary in width, making them very close together.

author: MrD
author_rank: Contributor
timestamp: April 10, 2020, 09:02:28 am
content: QuoteThat's a good observation! Though I can't see anything wrong there myselfOk, I'm going to contact PCBWAY and tell them what I've found, as briefly and directly as possible. I don't think I'll be able to get this board working, and it's nothing I've done. If I start messing with flux or knives, that's not going to help my ability to return the item.

author: NorthGuy
author_rank: Super Contributor
timestamp: April 10, 2020, 08:25:41 pm
content: Quote from: MrD on April 09, 2020, 10:14:26 amIf you're going to do any sort of prototyping, you'll have to learn to solder/unsolder parts anyway. I always need to re-solder things, cut traces, do other small fixes. It would take ages if I outsourced every little repair. Why not to start learning now? This is the perfect opportunity. Soon, you will be able to fix things, solder your own boards by yourself, etc.I had the best experiences with PCBWay. Usually their boards are perfect. They screwed up an order only once and they made me new boards without any hesitations. I don't do PCBA though, only PCBs. I'm sure if they screwed up your board, they will make you a new one. But it sounds silly to me to request a new board from across the ocean when you only need to re-solder one chip.

author: MrD
author_rank: Contributor
timestamp: April 11, 2020, 11:34:10 am
content: Thanks NorthGuy, but you're overestimating how well-equipped I am at present. If I was prepared to handle SMT, I wouldn't have used PCBWAY's service.I don't mind using it as a learning board, but only if I don't need it non-messed-up for PCBWAY's purposes first. Also, since this thing is designed to go into a fragile Mega Drive that's way more valuable than my project is, I'm very reluctant to throw bodgy boards about.I have done some trace cutting and bodge soldering on the previous Revision 0 if you're curious: I had to verify that some of my original bus control logic was incorrect - short version: I'd worked to the 68000 specifications, but didn't consider the behaviour of other devices on the bus which do read requests in a different way that doesn't use the 68000 signalling pins, so they ended up ignored.

author: MrD
author_rank: Contributor
timestamp: May 16, 2020, 10:00:26 am
content: PCBWAY asked to see a photo of IC1, so I sent it. They said that everything looked fine (which I already suspected), but said I should try reflowing the left edge. I personally think it's a bit weird for a manufacturer to be basically telling me to just have a go, but I said I'd pass it along to my engineers (i.e. me in the future when I have a flux pen) to look into.A line of flux and a bit of hairy but as calm as possible reflowing later (using a solder sucker for the inevitable balling on the final pin since I didn't have any braid available), and this second board is now passing all my tests, and as reliable as the other of my assembled boards if not better!I reported this to PCBWAY and they sent me a voucher to make up for the inconvenience.

author: NorthGuy
author_rank: Super Contributor
timestamp: May 16, 2020, 01:52:00 pm
content: Looks like I didn't overestimate you!

author: MrD
author_rank: Contributor
timestamp: May 17, 2020, 06:01:05 am
content: Hahawell I wouldn't be comfortable -selling- this board after my home-spun repair job at least! I haven't got any huge magnifiers to check if all the pins are 100% securely soldered - it's possible that some of them are simply resting on the pads depending on how the solder set I guess? Surface mount boards oughtn't to be made or repaired in an attic with a 25W iron, a flux pen and a solder sucker. Seems like a technological gap in my mind.But after testing every adjacent pair of IC pins for bridges (using the vias where I could), there's no sign of any strange behaviour and the Flash is throwing out correctly values to the Mega Drive as quickly as needed.

author: OwO
author_rank: Super Contributor
timestamp: May 17, 2020, 07:35:25 am
content: You can do shock & vibration testing to catch most soldering defects. You just need to hit the board on all 3 axis (6 directions) with a moderate amount of force.EDIT: this is probably obvious but you need to be running the functional tests during the shocks to catch transients; testing afterwards won't do the job.

author: kylehunter
author_rank: Regular Contributor
timestamp: May 18, 2020, 02:42:11 am
content: Quote from: OwO on May 17, 2020, 07:35:25 amI've been curious about vibration testing PCBs.. Do you have any info on building/buying a tester? Haven't been able to find much info on the topic.

author: OwO
author_rank: Super Contributor
timestamp: May 18, 2020, 03:02:35 am
content: Doing it "properly" is hard, there is a lot of mechanical design to get the forces correct. I'm investigating ways of building a simple vibration test jig. For prototypes and one-offs it's fine to do it manually.

author: KL27x
author_rank: Super Contributor
timestamp: May 18, 2020, 10:08:59 pm
content: 100% e-testing is not a given, even on a bare board. I use a manufacturer where that is an extra, for 2 layer PCBs. If you don't want to pay for e-test on this 2 layer board, they will still do visual inspection and x-outs,* and on a simple board this can be totally sufficient, and still result in a near-zero error rate (and effectively zero compared to other sources of issues). For PCBA, I don't expect any assembler to do e-test on the assembled board, unless you have arranged for that (at a great cost for a prototype, doh!). This might mean they request a schematic and firmware from you so they can create a testing process; or you have to create and provide them with this process/equipment. You can't do a generic e-test after a board is populated.This is gonna be harsh, my apologies in advance:QuoteYou don't "return items" to a pcb manufacturer. Never ever think that you're going to return a PCB to any manufacturer for the reason of a refund in circumstance such as this. They already did the work, and paid for the materials and components, and that assembled board is worth less than zero to them. No reason to return it unless for diagnostic for future board or for them to fix it. So if you wanted to, you could potentially make them fix it, but you would probably be charged for shipping to and fro. Because you did not order electrical testing after assembly. That is a big investment you don't do until you're ready to manufacture in higher quantity.YOU know there's a short because you know what the board is supposed to do. Did you expect someone else to infer that and learn every part that needs to be learned about the datasheets and communication protocols to reverse engineer and know exactly what your board does, just from looking at a bare PCB/gerber and a BOM? That there's some genius there who will do this for the pitiful $100 bucks a board you paid for a whole 2 of them? A customer with no contract for future guaranteed business, who can just go to any other manufacturer tomorrow? Insanity. Your engineers are the ones paid to do this; this should never have been emailed to the manufacturer/assembler.If you are going to make a fuss, they might issue you a refund, but more likely a credit. But they might tell you to keep the board and put it in your own garbage can. And possibly to take your business elsewhere.The only manufacturer/assembler who might bend over backwards to give you a refund is the middleman/broker who orders the stuff from china and charges you 300% markup. The Chinese manufacturers make you pay up front to avoid this bullshit. People like this increase my cost of business for the customer service problem they create. LOL. These manufacturers are doing the rote BS labor and exposure to chemicals and disposing of toxic wastes at an incredible price. This is why they have customers lined up, wiring money in advance, even if someone like you were to post how awful the customer service is, because you don't know what you're paying for or why. The rest of us pay for this slow and painful education for noobs, which these manufacturers have to deal with.*They're generally hypervigilant about this, X-ing out boards for the most minor and obviously inconsequential reasons. I've found some I never figure out why they failed in the first place. Even going so far as to populate and use a couple, just to see if they were really bad (no). Often they score through the copper. Maybe just in case the marker rubs off. Or maybe to prevent cheapskates from salvaging the actual good ones.

author: Psi
author_rank: Super Contributor
timestamp: May 18, 2020, 10:23:26 pm
content: You need to find someone near to you who can do SMT soldering. They will be able to pull the chips off and see if the short disappears, then put them back afterwards.From a SMT perspective your parts is not that complex, no BGA chips and the pin pitch isn't super small. So pulling chips off and putting them back on should be easy for anyone competent at SMT soldering.My guess is some solder paste got under the chip and is shorting between pins in a way you can't see externally.

author: MrD
author_rank: Contributor
timestamp: May 22, 2020, 08:38:56 am
content: Thank you for your answer KL27x, I appreciate it, and understand it. But I'm going to completely ignore it insofar as you're suggesting I just take it on the chin.I paid for two Zigs, and got a Zig and a Zag. That's 50%. Of course I'm going to follow through normal channels to get what I ordered (or an acceptable value of, which I did). I don't care whether it's difficult or hard or out of their normal workflow. I know it's difficult, that's why I paid someone else to do it.

author: ebclr
author_rank: Super Contributor
timestamp: May 22, 2020, 09:27:06 am
content: The 3rd pin up from the S29GL06...... counting from Led 1 is clearly in short

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 22, 2020, 09:35:26 am
content: All the tracks are spider thin with some odd angles... needs tidying up for Rev 2There is something odd going on at the top corner. There is a trace that appears to have solder on it but it just routes around the top chip (and goes very close to Pin1)Hot air off the top left chip and see what happens. You are going to need Hot Air at some stage?IMHO you shouldn't give PCBWAY a hard time over this; instead consider it a learning experience.

author: MrD
author_rank: Contributor
timestamp: May 22, 2020, 09:37:58 am
content: Quote from: ebclr on May 22, 2020, 09:27:06 amSee the following:Quote from: MrD on April 09, 2020, 01:38:22 pm

author: SMTech
author_rank: Frequent Contributor
timestamp: May 22, 2020, 11:12:26 am
content: Lets assume that to do this low volume low value job PCBway did what many of us would do and used the very cheapest method, a floppy unframed steel stencil some scrap PCB and some tape. The odds on slightly too much paste on this pitch pasted this way is fairly high and this method makes it far more likely the board doesn't get any kind of automated paste inspection before placement. Too much paste on fine pitch devices like these can easily cause a tiny short and its under the device nobody is going to see it. Factor in the possibility they placed the chips manually too and the risk increases. I suspect tooled up for a volume run it would be fine, it clearly wasn't a PCB fault (I have seen some slip through PCBway just like anyone else)The layout looks fine to me, no different to plenty of others I see, vias really close to the back of pads under devices can make this kind of fault more likely but I don't see that on yours. I would put it down to bad luck, they gave you a voucher, seems fair enough to me, the fact they are the other side of the world makes any other solution impractical to either party. Tbh even for one of our clients in the UK the odds are if a prototype had this kind of fault they probably would fix it themselves and possibly not even mention it. Different story if a chip needs to come right off of course. You should really have some braid and flux around the place anyway, everyone ends up cutting and modding a prototype at some point, manually working on a little bit of surface mount at this level isn't all that bad although I don't blame you for not wanting build the whole thing.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 22, 2020, 11:27:50 am
content: Quote from: MrD on May 22, 2020, 08:38:56 amAsk your local UK based subcontractor how much they would have charged to assemble those boards. At those prices you could maybe send one back for rework.The Chinese proto services are so cheap that you have to accept that they will not be perfect, and either do any minor fixups yourself, or order extras. You get what you pay for.If you are doing this sort of stuff, you absolutely need the capability to to minor reworks yourself, both to fix any manufacturing issues and to debug and modify issues due to errors in your design - it isn't difficult and the equipment costs peanuts these days. You could probably buy all the gear you need for less than a local assembly house would charge for the assembly.The only way to get guaranteed working boards from any manufacture is supply them with a test jig. This is not worth it for prototypes ( which could also have design faults anyway), so you just have to deal with these issues yourself.

author: OwO
author_rank: Super Contributor
timestamp: May 22, 2020, 11:30:57 am
content: Yes, generally I avoid using PCBA service for prototypes (except for JLC SMT). It's expensive as someone else has to figure out the details of your design, the rotation of the parts, then only to make 2pcs of it. Especially if you haven't already assembled lots of prototypes yourself this is important experience to have. Leaded packages like TSSOP and QFP should be a piece of cake, QFN/DFN are easy, and you should eventually aim to be able to do BGA and LGA as well.

author: SMTech
author_rank: Frequent Contributor
timestamp: May 22, 2020, 05:48:00 pm
content: Quote from: mikeselectricstuff on May 22, 2020, 11:27:50 amMinimal component count, so not much to setup or check, so I'd guess £100 - £200 1/2 of which will go to PCBway for the boards and stencil, not all that different from the quote you'd get from PCBway or Elecrow etc before they apply some ludicrous discount.