Got fabbed PCBs back, weird bodges

[cloudscapes]

Hey all,

So I just got a small (40) batch of PCBs back from a factory. They look okay except a few of them have some strange scrapes or smudges at exactly the same spot! Got a macro lens out and tried to get the best shot...



Tell me those don't look like "bandaids" layed out accross my traces then painted over with soldermask. At the perfect angle (that I can't capture with the camera) I can see extra soldermask was painted on, maybe with a brush, on top of those. You can almost see the outline of painted-on mask on the top bodge, along the bottom edge and a bit on the bottom part of the thick trace. Getting the light to reflect just right and I can definitely see an embossed bit of soldermask. Anyway, continuity checks out, but I'm still a bit disappointed. I'm just a hobbyist so I don't know if this is common.

Almost looks like something in the fab machine scraped through some traces at the exact spot for 5 or 6 PCBs.

Strange...



edit: 40, not 50

[Lurch]

I'd reject those without hesitation.

[marshallh]

Was the vendor pcbcart?

[Bored@Work]

Yep, ask for replacements.

I am surprised that they attempted repair. PCB repair is usually expensive and you don't do it for bog-standard PCBs which are easily reproduced. It could be they can do PCB repair very cheap (in China?), but well, the quality of the repair, judging from the first picture, isn't great.

[cloudscapes]

Was the vendor pcbcart?

silver circuits

at their defense, this is the second time I've used them, and I had no issues when I did last time a year ago.

[AndyC_772]

Reject the batch.

What's happened is that their transparencies have become contaminated, with the result that each board has track damage in the same place. They've attempted a repair - and sometimes these are acceptable - but they've not done a good job. Long term reliability is not guaranteed.

I sometimes tell a cautionary tale of the time this happened to a board I designed some years ago. They were made 4 boards to a panel, and almost 25% of them had a failed trace in exactly the same place.

What had happened was a tiny scratch on the artwork, so every board which was made in that position in the panel had a fault as a result.

This wouldn't have been so bad, except for the fact that we'd paid for bare board test, and had therefore assumed the boards we received were OK to use. So we did, and only found the fault once the boards were populated. Thousands of pounds' worth of brand new kit had to be scrapped.

We gave the PCB vendor hell, of course. The test operator's response? "I saw so many failures in the same place that I thought it was a fault with the test equipment, so I just let them all through anyway".

I think he lost his job over that one. 

[Lurch]

Now that I look at the picture again the component ID's appear to be illegible also. Seems to be a company to avoid.

[cloudscapes]

I'd reject those without hesitation.

Yep, ask for replacements.

I am surprised that they attempted repair. PCB repair is usually expensive and you don't do it for bog-standard PCBs which are easily reproduced. It could be they can do PCB repair very cheap (in China?), but well, the quality of the repair, judging from the first picture, isn't great.

I know in principal I should, but I had ordered extra. I ordered 10 more than I really needed at this point in time and 5 of them would be "unreliable", so I'm not that upset. I'm tempted to just not rock the boat. 

Though if this were actual work, then I'd probably do that.

The factory experienced delays with my order, a flood, according to them. Maybe the scrapes and fixes are a result of that.

[c4757p]

I find it particularly bad that they did it with a thick power trace. OK, this one's just feeding a couple linear regs, but in general, any time a trace is different from the rest, it implies that some calculation went into selecting it. Did they repeat that calculation? Of course not. Those little patch bits don't look particularly solidly attached to me. I wonder what the resistance is, and how warm they will get under load. Perhaps not enough to cause real trouble immediately, but perhaps enough to lead to premature failure?

cloudscapes, just to satisfy my curiosity, can you measure the resistance of that power trace bodge? Don't forget to account for probe resistance.

We gave the PCB vendor hell, of course. The test operator's response? "I saw so many failures in the same place that I thought it was a fault with the test equipment, so I just let them all through anyway".

I imagine an electrician saying "Well, I shut off the power, and I probed all the outlets and they all measured 120V! But since they're all reading the same it must be the meter. OK, go ahead! "

[Lurch]

I imagine an electrician saying "Well, I shut off the power, and I probed all the outlets and they all measured 120V! But since they're all reading the same it must be the meter. OK, go ahead! "

If only it weren't true. I have seen pretty much exactly this many times.

[cloudscapes]

I'll reply/comment some more later today.

cloudscapes, just to satisfy my curiosity, can you measure the resistance of that power trace bodge? Don't forget to account for probe resistance.

0 ohm on the 5 boards with the repairs, at least.

I managed to scrape off all the brushed-on mask with a knife. Yeah.... I won't be using these.

[Jay_Diddy_B]

Hi,

If any board receives a board with small pieces of track missing please contact cloudscapes, he has them.

I have never seen this in 25+ years in electronics business.

Jay_Diddy_B

[Bored@Work]

I know in principal I should, but I had ordered extra. I ordered 10 more than I really needed at this point in time and 5 of them would be "unreliable", so I'm not that upset. I'm tempted to just not rock the boat. 

Your choice. But I wouldn't let it pass, not even for hobby work. And if they wouldn't come up with replacements pronto I would put them on my personal supplier shitlist.

[bookaboo]

Never seen anything as rough as that on a new board. I'd reject immediately.

[Rufus]

I was surprised they repaired instead of scrapped them. Then I find silver circuits is on alibaba.com so cheap and Chinese - not so surprising.

There doesn't seem to be any sign of damage or repair in the other photo. I would reject the repaired ones asking for credit or replacement if you can't manage without them.

[amyk]

That's better than getting PCBs back all with broken traces there, no? It it works, use it... why waste the rest just for a little scrape.

[Psi]

Was the vendor pcbcart?

What made you ask that?
i've had many pcbs made by pcbcart and they have always been 100% perfect.

The bodge in the pic is something i would expect on the cheap places like itead

[Bored@Work]

That's better than getting PCBs back all with broken traces there, no? It it works, use it... why waste the rest just for a little scrape.

Because the "repair" might not last.
Because those not "repaired" might have the same fault or develop it under some stress.
Because that's not what he ordered.

[Lurch]

That's better than getting PCBs back all with broken traces there, no?

No. If they aren't what I ordered they would go back. If I ordered boards with gaps and scratches then I would accept gaps and scratches. If I didn't then I wouldn't.

It it works, use it... why waste the rest just for a little scrape.

I bet you wouldn't say that if you just bought a new TV with a few minor scrapes on the screen and bits of tape holding the back on.

[Poe]

Pay attention to the terms and conditions when you place your order.  If you're buying from some place like China, then it's caveat emptor regardless.  Although even USA vendors might say something like "small defects will be repaired to IPC standards." 

That's what you're seeing here.  This is more commonplace where labor is cheap.  I see this occasionally with our boards made in India.  Repairs done to IPC standards do not always produce a good appearance, but should be just as functional.  It's important to verify any repairs were done correctly if you don't trust the source.

It's hard to see if the copper was damaged or if it's just a solder mask issue.  Have you scrapped the mask off to see what exactly is under there?  That could be soldermask tape with liquid solder mask repair applied over top.  If the copper was damaged, they might have used copper flat ribbon soldered to the traces. 

[marshallh]

I would trash the boards and order from another place. PCBs can develop faults over time and several thermal cycles. It's happened to me, in fact, with the first and only PCBcart order I did, which someone got dust on the masks of. The result was tons of copper pinholes. Vias broke after 30-40 use cycles, traces seperated after a few weeks, etc. All of the pcbs failed within months.

[Mechatrommer]

if you live in a country like mine you may change decision, even if the boards are not repaired and do not pass test. a quick diy soldering will fix it. think about people doing "hobby" on perfboards, jumper wires all around like a rotten spaghetty, or even dead bugs on purely flat copper clad ground plan cut it using metal sheet cutter, put it in cadburry metal case. duh i've been mistaken that its not a "hobby".. short answer.. i'll take the board and the company is 100% sure in my shitlist until i get nothing else better.

[cloudscapes]

I got an $80 rebate for the next order (officially because of a few days delay, rather than the fixes), whatever it ends up being. Still unsure if I want to use them again in the future, though. Not just because of the fixes, but the silk could be a bit better too.

35 of the 40 are perfectly fine. I won't use the 5.

[scientist]

That's better than getting PCBs back all with broken traces there, no? It it works, use it... why waste the rest just for a little scrape.

Because the "repair" might not last.
Because those not "repaired" might have the same fault or develop it under some stress.
Because that's not what he ordered.

Jesus, chill your tits. This is a hobby board, and as OP said there are only 5 out of the 40 that are like this. You're being a bit heavy-handed.

[Bored@Work]

That's better than getting PCBs back all with broken traces there, no? It it works, use it... why waste the rest just for a little scrape.

Because the "repair" might not last.
Because those not "repaired" might have the same fault or develop it under some stress.
Because that's not what he ordered.

Jesus, chill your tits. This is a hobby board, and as OP said there are only 5 out of the 40 that are like this. You're being a bit heavy-handed.

No, because the "repair" might not last.
Because those not "repaired" might have the same fault or develop it under some stress.
Because that's not what he ordered.