Worst PCB Fails - Page 1
Forum section: electronics / projects

author: marshallh
author_rank: Unknown
timestamp: September 20, 2013, 08:05:29 pm
content: How to NOT route PCBs!Have a barf bag handy.And a couple of my own pcbs I'm not proud of:The internet never forgets...

author: Jebnor
author_rank: Regular Contributor
timestamp: September 20, 2013, 09:32:45 pm
content: Quote from: marshallh on September 20, 2013, 08:05:29 pmThat is actually quite clever. I'm going to use that the next time I need to route on a strip board.

author: free_electron
author_rank: Super Contributor
timestamp: September 20, 2013, 10:38:59 pm
content: AAAAAAAH My eyes !!!!time for a pair of new pants too...

author: krivx
author_rank: Frequent Contributor
timestamp: September 20, 2013, 11:29:36 pm
content: While most of the are awful, am I alone in thinking a few are just fine? The facedancer layout doesn't look too terrible to me...

author: JackOfVA
author_rank: Unknown
timestamp: September 20, 2013, 11:48:51 pm
content: Quote from: krivx on September 20, 2013, 11:29:36 pmVias under ICs are deprecated, but I've certainly done my share of PCB layouts with them.

author: Harvs
author_rank: Super Contributor
timestamp: September 21, 2013, 12:10:36 am
content: Quote from: Jebnor on September 20, 2013, 09:32:45 pmThat looks like one of the free tools to layout strip board. I don't think there's anything wrong with that, it's just what it is, it was never meant to be an etched PCB. Having said that, I've never found them terribly useful since the whole point of strip board is you can just grab it and start soldering.A few of those boards just look like someone has pressed go on altiums auto-router with all traces still at the default 10mil setting.

author: ovnr
author_rank: Frequent Contributor
timestamp: September 21, 2013, 12:19:02 am
content: Quote from: JackOfVA on September 20, 2013, 11:48:51 pmAre they now? Good luck finding a commercial product with a QFP or denser chip that doesn't have them...I actually kind of prefer having my vias under the chip. Looks neater when populated. Also, I always leave the solder mask on the vias - they aren't really test points, and if needed I will place a proper test point.Yes, obvious disclaimers about chips with heat slugs & other fun stuff here.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: September 21, 2013, 01:33:06 am
content: I notice marshallh put a couple of his own designs in the list. Lol kudos to you marshall. What was wrong with the Flash64 board? I can't see anything obvious apart from maybe track width.There was at least one of the boards that left me wondering. Facedancers as mentioned before.So the main faults are apart from crazy routing.Lack of ground planelack of ground floods.90 degree bends (controversial I realise)Long diagonalsinappropriate sized tracks, too smallobvious use of autoroutermaybe should have used a four layer boardlack of mount holesnot using one layer as default vertical and another horizontalnot running parallel traces in a graceful mannernot connecting all padscomponent placementcomponent orientationlack of decoupling capsif anyone has any other faults they can see please list them.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 21, 2013, 01:44:59 am
content: Quote from: HackedFridgeMagnet on September 21, 2013, 01:33:06 amRandom trace angles. OK, the electrons don't care, but it looks disgusting.Many, many, many cases of 'failure to just look at it and re-route to eliminate vias and needlessly close clearances'.You already noted "Groundplane? What is groundplane?"

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: September 21, 2013, 02:12:27 am
content: maybe a wrong name, but a layer just with a ground flood on it. So unbroken except for vias. On a four or more layer board.Yes clearances.

author: mrflibble
author_rank: Super Contributor
timestamp: September 21, 2013, 02:48:41 am
content: Quote from: JackOfVA on September 20, 2013, 11:48:51 pmHow so? I can't really think of something inherently wrong with them.

author: Clear as mud
author_rank: Regular Contributor
timestamp: September 21, 2013, 04:00:19 am
content: Quote from: TerraHertz on September 21, 2013, 01:44:59 amActually, I thought that one in the middle with the random trace angles looks pretty good. Creative. I use Kicad, and it can't do that. That almost looks like it was drawn by hand. I'm talking about the one with the white background, red and blue traces, with the text referencing Evil Mad Scientist. I would have routed it differently, and put a ground plane on at least part of it, but I like the fact that the trace widths make sense.

author: c4757p
author_rank: Super Contributor
timestamp: September 21, 2013, 04:16:35 am
content: Quote from: Clear as mud on September 21, 2013, 04:00:19 amYes, it can.Edit: Well, I didn't notice the rounded corners, I just saw the random angles. You're right, it doesn't do rounded corners.

author: Psi
author_rank: Super Contributor
timestamp: September 21, 2013, 04:20:42 am
content: Only about half of them look terrible. Most of the others aren't too bad.Some of them haven't even been finished, so judging isn't really fair.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 21, 2013, 04:21:42 am
content: Quote from: Clear as mud on September 21, 2013, 04:00:19 amThat one is quite curious. If almost looks like it was done with tapes, old-style. The radius bends suggest that. But then there are bends of small angles with no radius. Weird.Have to admit I tended to use random angles too, back in the tape-on-film days.

author: sleemanj
author_rank: Super Contributor
timestamp: September 21, 2013, 04:36:29 am
content: Quote from: TerraHertz on September 21, 2013, 04:21:42 amSays it's based on the Diavolino which is a particularly sexy looking arduino uno footprint (I have one in a drawer here somewhere)...if I remember rightly the explanation for "why the curvy traces" was that they were actually (largely) auto routed with some router that gives curvy traces.

author: ResR
author_rank: Regular Contributor
timestamp: September 21, 2013, 07:41:44 am
content: Too many auto routed pcb-s, makes my mind itch for some manual action with them. Few even look like it was unfinished & dumped. Thanks for sharing OP.

author: free_electron
author_rank: Super Contributor
timestamp: September 21, 2013, 09:35:07 am
content: Quote from: sleemanj on September 21, 2013, 04:36:29 amThey used the topor router. Some russian router that routes with arbitrary angles. Butt ugly boards.Anyway. Les gouts et couleurs se discutent pas ... Colors and tastes are not discussableMany of those boards look like some autorouter vomited them.Autorouters are a funny thing. They work on the principle of garbage in , garbage out . The extreme case is nothing in means i get to do whatever and will create absolute chaos.Autorouters can work , provided you feed them criteria. The problem is that, for many boards, the time spent to set up the routing criteria to get the thing to do what you want takes longer than drawing it yourself in the first place.Which is why almost all pcb layout people use the routers in interactive mode.

author: nctnico
author_rank: Super Contributor
timestamp: September 21, 2013, 10:26:56 am
content: Quote from: JackOfVA on September 20, 2013, 11:48:51 pmIn many cases you can't avoid vias under ICs. Think about BGA for starters or a good connection to supply and ground planes.All in all most of the layouts aren't that bad. I like the 'any angle' line approach. Takes me back to using thin black tape and rub-on footprints to create a PCB layout on transparent plastic. OTOH nowadays its better to use one layer mostly as ground (even on 2 layer boards) and put most of the traces on the top layer.

author: Zbig
author_rank: Frequent Contributor
timestamp: September 21, 2013, 10:37:00 am
content: Quote from: JackOfVA on September 20, 2013, 11:48:51 pmWhaaa? So you're basically saying that what I've done below is neither cool NOR smart? You're killing me. So sad now

author: amyk
author_rank: Super Contributor
timestamp: September 21, 2013, 10:46:46 am
content: That arbitrary-angle routing is interesting, it's optimising total trace length so traces that can run in a straight line will.Some of the boards could be made much denser but otherwise I'm not one to judge; it's "whatever works" for me, and in any case, if it's going in an enclosure for most of its life no one will look at it... teardowns notwithstanding.

author: JackOfVA
author_rank: Unknown
timestamp: September 21, 2013, 03:04:47 pm
content: Quote from: Zbig on September 21, 2013, 10:37:00 amI'm probably a bit older than most of the board members and started out with tape layouts and Rubylith and double sided boards that either did not have plated through holes or if they were the quality of the through hole plating was not always the best. If you have to solder a jumper between the top and bottom layers to complete the via or to repair a non-functional via, it's not so easy when the via is under a component. Consequently I've carried over those practices, without really considering whether that's necessary now.PCB manufacturing has come a long way since then and with electrical testing of the board (or even without) it's rare for me to find a bad board, and when it is bad, it's usually a pad that was incompletely etched and is shorted to ground. Can't recall seeing a bad via in the last 10 years or more.And yes indeed, complex chips have to have vias under the IC, so times change and so do layout practices.

author: mrflibble
author_rank: Super Contributor
timestamp: September 21, 2013, 03:24:24 pm
content: Since you used the word "deprecated", that would suggest "was acceptable practice in the past, but nowadays we don't do that anymore because of <fill_in_reason>". But if I understand you correctly it's just an old habit? Phew, my layouts are safe!You did have me thinking there for a minute ... what the hell did I miss? O_oSo it's more like "the rule to NOT have a via under IC's is deprecated" because 1) increased density and 2) better quality via's than eons ago.

author: IanJ
author_rank: Unknown
timestamp: September 21, 2013, 03:25:46 pm
content: Quote from: JackOfVA on September 21, 2013, 03:04:47 pmHi all,When I first joined the oil industry in electronics early 1980's the company I was with was just starting to leave tape and layout pcb's with SmartWork (Wintek), however, we were still etching our own boards so via's (or track pins as we knew them) were a no-no under IC's etc.A couple years later and still with the same company we eventally started buying in our PCB's and of course used THP. Designing the first few THP boards I had to remember THP via's under IC's are ok!.I think a lot of the old habits are still valid today though......things like keeping as many tracks on the bottom layer as possible especially when interfacing to a DIP pin......we always had the view that if the IC needed removal it was a pain when there were topside tracks.Ian.

author: envisionelec
author_rank: Frequent Contributor
timestamp: September 21, 2013, 05:01:12 pm
content: Quote from: HackedFridgeMagnet on September 21, 2013, 01:33:06 amWrong trace width for current carrying (Motor Controller)Short CircuitsWasted Space

author: AndyC_772
author_rank: Super Contributor
timestamp: September 21, 2013, 05:21:48 pm
content: There's no reason at all to avoid putting vias under ICs. I've heard of it being a problem a long time in the past - well before I started designing boards professionally - but I don't remember any manufacturer ever even suggesting to me that it's a problem now.If you think they might be an issue under a QFP, think for a moment about how BGAs are always escaped and routed.

author: WarSim
author_rank: Frequent Contributor
timestamp: September 21, 2013, 06:24:53 pm
content: Here is something not mentioned on the via under chip subject.When users must continue to support and repair cards long after the designing company has moved on buried and hidden via are harder to repair. It is sometimes very hard to tell what levels are involved in buried vias, and requires stronger editions to get through covering copper and IC. Under IC vias are annoying because more parts need to be removed for repair and correcting wrong schematics is more labor some.Please no naive comments about 5-10 year product lives. This silliness would cost trillions in waist and vastly increase our e-waist problems.Please no propriety rights delusions. Propriety it is something to be respected, but these rights are in default in several circumstances that happen all the time. The designers remember their rights but very rarely remember their responsibilities to maintain their rights.

author: Unknown
author_rank: Unknown
timestamp: September 21, 2013, 06:33:47 pm
content: Quote from: WarSim on September 21, 2013, 06:24:53 pmI'm sorry but I don't think a manufacturer is going to care whether or not you you find it difficult to repair a product that they discontinued and stopped supporting years ago. This is pretty much how most things that I repair are designed, for streamlined assembly. Field repair is not really a design concern any more. This is why I end up bleeding and/or swearing at most jobs that involve some removal and refitting of some component or device within a product.

author: AndyC_772
author_rank: Super Contributor
timestamp: September 21, 2013, 08:10:13 pm
content: What next, please refrain from using multi-layer boards because they're harder to reverse-engineer? Please don't ever use a programmable device? No ASICs or any other custom components?

author: David_AVD
author_rank: Super Contributor
timestamp: September 21, 2013, 10:24:24 pm
content: I place vias under SMD parts all the time. Sometimes it helps avoid breaking up the ground plane. Other times it allows achieve a higher parts density for the available real estate.

author: ElectricGuy
author_rank: Regular Contributor
timestamp: September 21, 2013, 10:44:09 pm
content: Quote from: marshallh on September 20, 2013, 08:05:29 pmCan somebody tell me what is wrong with this two, besides the silkscreen getting out of the board?

author: c4757p
author_rank: Super Contributor
timestamp: September 21, 2013, 10:50:47 pm
content: I don't think there's anything wrong with them. If somebody can think of a better way to route a large number of signals to a large number of connectors that are out of order, all on a two-layer board, I'm all ears.Look closely at them, though, they're unfinished. None of the grounds are routed. Maybe this is meant to be a four-layer with an internal ground plane. In that case, I'm even more OK with that routing.

author: ElectricGuy
author_rank: Regular Contributor
timestamp: September 21, 2013, 10:51:25 pm
content: Quote from: c4757p on September 21, 2013, 10:50:47 pmX2

author: digsys
author_rank: Unknown
timestamp: September 21, 2013, 11:17:25 pm
content: Quote from: ElectricGuyThere's nothingwrongwith them "as such". If it's only a prototype / limited run / don't want to do manual routing,then no one can really say it's wrong. For production though -The less vias the better, more junctions that can go wrongOptimising track lengths, keeping buses together, keeping analogue / digital separated etc etc help reduce EMI, cross-talk etc etcPlus, a well laid out PCB increases peoples perception that you "know what you're doing" or "give a shit" or you're "a professional".I see that many many times. Irrespective if it's true or not !I personally take pride in my layouts, and can take an extra day to get it "perfect".

author: WarSim
author_rank: Frequent Contributor
timestamp: September 21, 2013, 11:37:04 pm
content: Quote from: AndyC_772 on September 21, 2013, 08:10:13 pmHere are the facts. Given two systems that achieve the requirements. One is harder to support when the product is dropped that the others. The one that is easier to support will be purchased. I know companies have lost billion dollar contracts for this exact reason. Yes it is entirely the manufactures right to loose any contract for any reason. I am not challenging anyone's rights. I just made note of a consideration.As far as reverse engineer, refusal to supply documentation upon refusal to support will also cause ejection from the selection process.

author: ovnr
author_rank: Frequent Contributor
timestamp: September 22, 2013, 12:37:56 am
content: Quote from: WarSim on September 21, 2013, 11:37:04 pmAnd now you're talking about a whole different market. Hey, let's pop open ALL the $500k oscilloscopes and inspect them for beingdifficult to servicewhen discontinued! And then make the supplier pay by NOT dealing with them! Yeah right. I doubt very many companies even consider trying to have highly integrated high-end equipment repaired beyond a cursory peek; if so, it's something so hilariously specialized that it's not even worth mentioning in a discussions about wholly mundane PCB designs.Please point me in the direction of something designed in the last 10 years that was designed to be reverse-engineered and serviced without any supplied schematics and diagrams.

author: WarSim
author_rank: Frequent Contributor
timestamp: September 22, 2013, 02:34:25 am
content: Quote from: ovnr on September 22, 2013, 12:37:56 amI never claimed I was speaking of your market nor every market. Nor did I claim the markets I have been involved in are the only markets. I brought up a consideration. Since then you have been having these strange reactions to my posts. I just mentioned a consideration. If after your consideration and it doesn't apply to your circumstances, then you have considered it and made your decision to do something else. I really don't see the problem, apparently you are having a large problem.Shall I remind you of the last sentence of the post you are responding to? If the manufacturer fail to supply their data, the fines will be large enough to replace all the effected equipment with products of another manufactures so no problem. And, yes it is certainly within the rights of any company to decide to buy what they want from anyone they want for whatever reason they want.Besides what is so difficult about servicing the 500k scopes made in the last 10 years? We have and do for that matter lets include on more expensive scopes we also service and repair. Yes we have limits to what even we can do but it is usually based on repair cost and not ability. Spending a week rebuilding a broken 16 layer board is rarely (not never) cost effective. Utilizing second source for parts and components is economically viable. In my opinion tossing a $6,000.00 card from a $800,0000.00 item due to under $600.00 in parts is just silly. It is even economical on occasion to replace parts with a functional equivalents. Obviously what you can repair is also limited by available resources such as thermal imaging resolution, x-ray resolution etc. I assumed it was obvious when i typed my previous posts.If anyone wants to stay with the small companies and stay out of the large contracts, do what you want. It really doesn't matter. Frankly it is becoming irrelevant to me also because I am retiring soon. Why would I care what market anyone enters, they are capable of making their own decisions. Even if a company wants to make the largest contribution to the landfills, it is still their decision. I just hope they will decide differently. I have seen business rise and fall, it is the nature of business. Everything works out in the end, one way or another.BTW I do understand that consumer electronics are the largest market with many smaller ventures and many competitors. But I would never suggest nor imply that it is the only market. There are very lucrative smaller markets with fewer competitors out there. Again everyone has the right to choose their course, and without being harassed by others.

author: senso
author_rank: Frequent Contributor
timestamp: September 22, 2013, 02:42:19 am
content: Quote from: c4757p on September 21, 2013, 10:50:47 pmIts Eagle, and the planes are there marked as the dotted lines, just press Rats-Nest and it will generate the ground-planes, they didn't that in the photo to preserve visibility of the screen-shots.

author: AndyC_772
author_rank: Super Contributor
timestamp: September 22, 2013, 08:41:02 am
content: Quote from: WarSim on September 21, 2013, 11:37:04 pmThat's your opinion. In my experience, which clearly differs from yours, the product that gets purchased is one which meets the specified requirements for functionality and cost, and on who is the 'preferred', currently fashionable supplier for that type of product. Company politics, features, price and whether or not the product looks cool all are at least as important as any servicing considerations.Making a competitive product inevitably results in design decisions which can make servicing harder - though even then, I'd have rated 'vias under ICs' as being so completely trivial as to not being worth even a cursory mention. They're not a reason why a board can't be fixed... unobtainable ASICs and programmable devices are.The days of the double sided board with big, chunky through-hole passives and DIL ICs are gone forever, and multi-layer boards with BGAs are here to stay. Deal with it.

author: WarSim
author_rank: Frequent Contributor
timestamp: September 22, 2013, 08:53:24 am
content: Certainly our experiences have been different, therefore have different opinions. My personal experience includes some very specialized areas. I conceded that of my 40 years experience only 15 has been in the more general areas.

author: Unknown
author_rank: Unknown
timestamp: September 22, 2013, 09:00:51 am
content: Quote from: WarSim on September 21, 2013, 11:37:04 pmIn very rare cases maybe. On the whole the product that will perform the required duties for the required time period will be purchased at the lowest price. The lowest price one will be the one that is a nightmare to service due to the design decisions to make it easier to assemble, not to take apart. A product designed for serviceability is a very niche product and will be many times more expensive than the unserviceable one. Weighing up all the options you can usually make a case for throwing away the unserviceable cheap one and buying a new one every X Years rather than repairing the expensive one. There are advantages to this also in that you may get updated hardware, brand new warranties, better support on new products... which leads us back to the start.In short, you're in a minority these days. No-one repairs anything any more in a commercial environment.

author: Neilm
author_rank: Super Contributor
timestamp: September 22, 2013, 09:18:49 am
content: Quote from: Lurch on September 22, 2013, 09:00:51 amDepends where in the world you are and what business you are in. I know that there are some places in the world (far east especially) that will want to repair failed equipment rather than get new. We have a lot of trouble at work getting premature failures of new equipment as they want to repair it.Generally though, it is a case of "change board x" rather than fault finding the PCB.

author: AndyC_772
author_rank: Super Contributor
timestamp: September 22, 2013, 09:19:45 am
content: Not just cost, but size, weight, power and functionality too. The same design techniques which allow all these things to improve over time also end up making products harder to service and repair.What I do find noteworthy is that, although design engineers seem to readily accept the need for change and to learn new skills and develop capabilities, repair technicians (in my experience) seem much less willing to do so. That's a people problem, not a technical one... it's much easier to complain that a product isn't simple to repair than it is to learn how to repair a newer design.

author: amyk
author_rank: Super Contributor
timestamp: September 22, 2013, 02:01:52 pm
content: Quote from: AndyC_772 on September 22, 2013, 09:19:45 am"in my experience" - that would be a Western one, correct? As Neilm alluded to in the post above, there are numerous shops in the East, particularly Asia, that are more than willing to do component-level repair on the latest electronics, at very low prices. There's a "reball-while-you-wait" stall in theSEGthat my friend tried once; it was cheap and the actual process took less time than waiting in the queue of others wanting the same service...

author: Unknown
author_rank: Unknown
timestamp: September 22, 2013, 03:22:14 pm
content: Quote from: amyk on September 22, 2013, 02:01:52 pmSure people can still repair stuff, some areas/regions more so than others, but that has nothing to do with the manufacturers design decisions, which is what this was about.So yes, people will still repair things, no the manufacturers don't design products with 3rd parties in mind.

author: Dreso12
author_rank: Contributor
timestamp: September 23, 2013, 08:56:53 am
content: For me the problem with vias below ICs is that if you use too much solder paste you can have shortcircuits between pads and vias below the component.This might not be much of a problem if you solder manually or use stencils but it can be a pain in the ass if you use manually dispensed solder paste and an oven or a hot air gun. Rework is nearly imposible in this case as the shortcircuit is not accesible.

author: David_AVD
author_rank: Super Contributor
timestamp: September 23, 2013, 09:53:23 am
content: I've never found that to be a real world problem. If you're using that much paste, you will have bigger problems to sort out.

author: mrflibble
author_rank: Super Contributor
timestamp: September 23, 2013, 12:16:19 pm
content: Quote from: Dreso12 on September 23, 2013, 08:56:53 amAt the risk of stating the obvious, don't use that much paste then. You can get away with quite small amounts. And just in case, dispense it more towards the outside.

author: Mattylad
author_rank: Regular Contributor
timestamp: October 02, 2013, 08:19:30 pm
content: Why do some of those boards have square vias?I have never understood why make them square.Some real candidates for some PCB layout training in the OP though

author: Poe
author_rank: Frequent Contributor
timestamp: October 03, 2013, 03:01:21 am
content: In an effort to make this thread productive, maybe we could post a personal layout fail and point out why?We all start somewhere.Once at work I'll post my failed layouts and why they were wrong.

author: Dago
author_rank: Frequent Contributor
timestamp: October 03, 2013, 02:20:18 pm
content: Quote from: Mattylad on October 02, 2013, 08:19:30 pmI think the answer is because Eagle has square vias by default. Why eagle has square vias by default that I do not know

author: Neilm
author_rank: Super Contributor
timestamp: October 03, 2013, 04:29:55 pm
content: Quote from: Mattylad on October 02, 2013, 08:19:30 pmI've seen square vias used for test points. They stand out when you are looking at the board.

author: MacAttak
author_rank: Unknown
timestamp: October 03, 2013, 05:56:41 pm
content: Yeah, it is nice for marking PIN 1 for things like ISP programming test points and stuff like that.It is the default in Eagle, but that default can easily be changed to octagonal or round.Mostly just a personal style thing I think. Perhaps round via pads will go out of fashion one day and all the cool kids will want square pads there instead.

author: Zbig
author_rank: Frequent Contributor
timestamp: October 03, 2013, 10:07:43 pm
content: Quote from: Mattylad on October 02, 2013, 08:19:30 pmWhen doing the layout the fragment of I attach (again), I found it easier to eyeball the distances between both different vias and their neighboring traces and decide whether I've already crammed it to much or not. I feel I'd have much harder time gauging that had the vias been round. And yes, I realize that probably I should have been relying on properly configured DRC insteadAlso, aren't squares easier to get when using any manufacturing technology which involves moving some mechanical devices with stepper motors (like milling), etc?

author: David_AVD
author_rank: Super Contributor
timestamp: October 03, 2013, 10:21:33 pm
content: Round vias can be placed closer together (or give more diagonal clearance) in a staggered arrangement. I can't say I've ever seen square vias on a consumer electronics PCB.

author: WarSim
author_rank: Frequent Contributor
timestamp: October 04, 2013, 07:11:57 am
content: Yes pad and via shape in most cases are preference but there are situations where a certain shape is required. I don't want to get into physics, explaining why, then receive rude comments that it is so rare. Even after I said most times it is preference based, ergo the inverse of most is seldom at best.What I have found is on a rare occasion a board requires a few uncommon pad shapes. The designer thinks the board looks odd with life rent shaped pads, so they convert the inconsequential pads to conform to a layout convention. Because people like to compare their work with others the different board is seen and some will like the new style and adopt as a new preference. Now it is common place to have round, square, octagonal. long and offset as common layout options. I accept most people haven't see what I have seen and do not agree. All I can say is layout preferences, requirements and methods have changed over the decades.I still work on and repair epoxy board that is now completely clear, and also brand new. Put two low density boards specialty boards made with similar methods made several decades apart, the differences are profound. No the new board is not an improvement on the old. The new design using the "new" methods had to be scrapped and the old board repaired for use. When the boards where compared side by side the people responsible for making the replacement finally accepted what they refused to consider. They where told about the gotchas but they knew better. Several of the considerations missed are now considered in-consequential, in most cases.I am not suggesting designers need to know everything about every exception. It just bugs me that people refuse to learn from others, and insist on making the same mistakes for themselves. It is such a waist of time and money.

author: WarSim
author_rank: Frequent Contributor
timestamp: October 04, 2013, 07:24:15 am
content: Quote from: David_AVD on October 03, 2013, 10:21:33 pmIn most cases I can main ordinal paths, so I find octagonal pads are better for higher density stuff. But round look sleeker.To respond to the milling comment in another post. I have personally not found any pad shape concerns when milling. It will mill through any space of any shape it has a tool to get into. The one restriction I have found is with high density low power very high frequency boards. Milling effects the substrate too much and approximates the pads too much for the results I want. So I just don't DIY anything over 500MHz. It's a hobby so I don't have to.

author: marshallh
author_rank: Unknown
timestamp: February 17, 2016, 04:57:01 am
content: This was too good to not post here.

author: KL27x
author_rank: Super Contributor
timestamp: February 17, 2016, 06:24:22 am
content: That was obviously a test board to verify the conductance of all the vias, before testing of the patent-pending asymmetrical J1 connector begins.

author: MarkF
author_rank: Super Contributor
timestamp: February 17, 2016, 07:14:04 am
content: Can everyone critic a PCB layout that gave me a lot of trouble to route.Although I'm a EE, my 35 year career has been doing software development. One of my hobbies has been in model railroads and I'm designing a computer interface for my layout. This board is 1 of 4 types that must communicate with each other: a USB interface, Analog outputs, Relay outputs and Sensor inputs.

author: Rerouter
author_rank: Super Contributor
timestamp: February 17, 2016, 09:17:18 am
content: To mark,First up, your capacitors C1-C5, put the caps closer to where they are needed, you have your main positive and negative pin right next to one another, so use that, this will also help reduce coupling between your positive rail and signals, (plenty of room between the chips)Play with your planes, you should be able to specify using spokes rather than hard connection, as it will be very hard to get reliable joints with such large planes,Other than that, apart from possibly grouping the digital signals a bit tidier, it looks ok,

author: obiwanjacobi
author_rank: Super Contributor
timestamp: February 17, 2016, 09:28:27 am
content: A very interesting (old) thread but if you want somebody to learn from it, it helps to state what is 'sub-optimal' and why? I am looking at several (of the older) boards but cannot see what the problem is. It is too easy to just publicly bash other peoples boards and not tell them how you think they could improve on it.

author: Rerouter
author_rank: Super Contributor
timestamp: February 17, 2016, 09:45:35 am
content: obi, most of the examples on the first page appear to be autorouted boards, key points i can see is components spread out dramatically, vertically only on one layer, and horizontal on another.There is an example of stripboard routing, which is likely just something the op may have not seen.Others of minimum distance routing, again by an autorouter, they look odd to the people used to using 45 degree increments, and again in some cases, better component placement before running the router would have resulted in shorter traces, which for most cases is the ideal,

author: obiwanjacobi
author_rank: Super Contributor
timestamp: February 17, 2016, 09:50:22 am
content: Quote from: Rerouter on February 17, 2016, 09:45:35 amYes, some were very obvious, but still, why would vertical on one side and horizontal on the other side be bad, really?They did that all the time in the computer boards in the 80s. It allows for great density of components and therefor smaller board size (doesn't it?).

author: Rerouter
author_rank: Super Contributor
timestamp: February 17, 2016, 10:03:47 am
content: As always it depends on the desired outcomes, its considered an old practice, so looks out of place to some designers, equally other routing patterns generally lead to shorter solutions, without sacrificing density,My reference point for this is generally its better to avoid vias on signals with fast edges, so jumping through 2 on most signals seems like asking for trouble,

author: obiwanjacobi
author_rank: Super Contributor
timestamp: February 17, 2016, 11:05:14 am
content: I understand. What speed do you deem 'fast'? 10Mhz, 50MHz or >100Mhz??

author: EEVblog
author_rank: Unknown
timestamp: February 17, 2016, 01:15:09 pm
content: Quote from: Poe on October 03, 2013, 03:01:21 amLaying out at 500V DC power supply once I accidentally put two high voltage traces too close (got every other trace correct, missed that one) and when powering up the first prototype it was sitting on top of the test report sheet which promptly caught on fireThe burnt test report sheet was submitted as-is with red circle and an explanatory note! (back when you actually submitted and archived real paper reports).

author: brabus
author_rank: Frequent Contributor
timestamp: February 17, 2016, 01:35:53 pm
content: Quote from: obiwanjacobi on February 17, 2016, 11:05:14 amAs Rerouter said, frequency itself has actually very few to do with EMC issues; what matters is the edge sharpness. I learned it the hard way when facing EMC emission issues coming from a reset line switching once in a while (thus, very low frequency indeed): the edge was very sharp, spitting harmonics all over the place.The exact frequency of the harmonic that will cause you problems is the only one you didn't care during design.

author: jeroen74
author_rank: Frequent Contributor
timestamp: February 17, 2016, 02:15:15 pm
content: Stupid layout mistakes I made that I can remember:* Mirroring one half of the edge connector on an ISA card* Using a 20 pins footprint for a 16 pins IC, so I had to dead bug wire the 8 other pins, not that funny with TSSOP* Following the advice from a fellow engineer to place and determine number of required decoupling caps last because you don't know where to place them until you have finished initial placement. Of course, I forgot them