From Schematic to PCB - Page 1
Forum section: electronics / general

author: dellsam34
author_rank: Regular Contributor
timestamp: May 18, 2021, 04:27:07 am
content: I have the attached schematic for an old school motor control and I want to make it on a PCB for ordering, My question is how much it would cost to have a PCB design file ready for ordering? I haven't order the electronic components yet, just looking for some advice, I've included links to some components.The original board is part of a big system control board, I've isolated the section that controls the motor which what I need and I want to make a small PCB for it, I already have the transformer TR. and the motor SCM-200.List of electronic components:Resistors:- R1 4.7KΩ- R2 1KΩ- R4 220Ω- R5 2.7KΩ- R6, R7,R10, R13, R24, R25 10KΩ- R8, R22 1.5KΩ- R2, R11, R23, R26, R27 1KΩ- R9, R12 100KΩ- R14, R19, R21, R32 3.3KΩ- R15 39KΩ- R17, R18 22KΩ- R28 330Ω- R29 180Ω- R30 100Ω- R31 56KΩCapacitors:- C1 Elect. cap. vertical 2200uF/35WV ->https://www.ebay.com/itm/184481088505?hash=item2af3ee03f9:g:6ywAAOSwgiZfgBdw- C2 220/35 ->https://www.ebay.com/itm/173287185970?hash=item2858b89e32:g:jTYAAOSwhvFZJk3e- C3 22/25 ->https://www.ebay.com/itm/143803710809?hash=item217b5e7d59:g:Qw4AAOSwzcdfk8MN- C4 Elect. Cap.vertical 1000uF/25WV ->https://www.ebay.com/itm/390977634935?hash=item5b08154277:g:L3oAAOSwKrxUagNX- C8 100/16 ->https://www.ebay.com/itm/173243800293?hash=item2856229ae5:g:bT0AAOSwKfVXFkh2- C9 0.12(K) -||-- C10 0.01(K) -||-- C11 10/15 ->https://www.ebay.com/itm/173373908900?hash=item285de3e7a4:g:uy8AAOSwIgNXqvjt- C12, C15 1/25- C13 0.0033(K) -||-- C14 0.033(K) -||-- C16 0.33/50(K)- C17 10/16- C18 1/100- C20 Metallized film cap. vertical 3.5uF(K)/180WV- C56 22/25Diodes:- D1 Silicon Bridge Diode SVB10-100 ->https://www.ebay.com/itm/200915990145?hash=item2ec786b681:g:zPEAAOxyn9BRbCjW- D2 Zener Diode HZ22-3 ->https://www.ebay.com/itm/294044174113?hash=item4476660721:g:jrYAAOSwXYtY2Wax- D6 Zener Diode WZ-120 ->https://www.ebay.com/itm/264359189910?hash=item3d8d091d96:g:wlgAAOSwTKBamBUf- D7, D8 Silicon Diode 1S2473 VE ->https://www.ebay.com/itm/254599068844?hash=item3b47497cac:g:IVoAAOSw4f5YCHwl- D9 Silicon Bridge Diode SVB10-200 ->https://www.ebay.com/itm/192835621634?hash=item2ce5e61302:g:8UwAAOSwo3xccHRFTransistors:- TR1 2SC1061 (B)(C) YC-408 ->https://www.ebay.com/itm/324030185415- TR2, TR4, TR5, TR6, TR7, TR8 and TR11 2SC945L (Q)(P) ->https://www.ebay.com/itm/265163866373- TR9, TR10, TR12 2SA733 (P)(Q) ->https://www.ebay.com/itm/324519219622?var=513577327133- TR13 2SC2336B (Q)(P) ->https://www.ebay.com/itm/281038917605Variable Resistors:- VR1 Semi-fixed / Vol. V18K3-6 (4US) 50KB ->https://www.ebay.com/itm/124719229345?hash=item1d09d869a1:g:0QoAAOSwXq5ZqRgt

author: jpanhalt
author_rank: Super Contributor
timestamp: May 18, 2021, 11:52:46 am
content: Given just what you have posted, you will need engineering help to decide which components to use. For example, for a simple resistor of a given value, there are hundreds of choices. Once all the components are properly defined, then you need to define the type of pcb, e.g., approximate size and number of layers. Do you want the old transistors to be soldered or socketed? Can you find all the parts?Just a guess from my own experience, but once everything is defined, I would expect about 3 days (24 hours) to get a first draft. After that, maybe a day or two for revisions. I don't have a clue what such services cost per hour, but I suspect you are talking thousands, not hundreds of dollars. Remember, that does not include engineering costs.I suggest downloading a free version of some common software and learning to do it yourself. If your purpose to to get a motor speed control and not to duplicate a vintage design, it will be much easier to start with modern chips and designs.

author: dellsam34
author_rank: Regular Contributor
timestamp: May 18, 2021, 01:03:30 pm
content: This is just for one single board, definitely not for production or that budget scale. I can get all the components and I know what to get, The PCB is a single layer with old fashion soldering method, no surface mounted components, I know I can get it made for less than $50. The part I'm inquiring about is the schematic to Gerber phase.I've edited my original message to include some links to components, Please advise if wrong component chosen.

author: Bassman59
author_rank: Super Contributor
timestamp: May 18, 2021, 03:58:07 pm
content: Quote from: dellsam34 on May 18, 2021, 01:03:30 pmThat is called "PCB layout" and is a significant task. If you don't know how to do this, you can contract it out, but don't expect anyone to do it for free because it's actual work.

author: dellsam34
author_rank: Regular Contributor
timestamp: May 18, 2021, 04:22:19 pm
content: Thanks, No I'm not expecting free service, I'm just looking for tips and advice. Worst come to worst I can lay down the components the way they are on the schematic and just run the copper traces as shown in the schematic.

author: Proto
author_rank: Contributor
timestamp: May 19, 2021, 04:24:43 pm
content: Take a look at ExpressPCB's site. View the tutorial video(s). The schematic and PCB layout tools are free. Make you board 2 layers so you don't go through contortions getting everything connected. The PCB tool feeds into their manufacturing system so you don't go through the intermediate step of producing a set of Gerber files. I can't think of an easier way to get the results you are looking for than this.

author: DIYGUY Chris
author_rank: Contributor
timestamp: May 19, 2021, 04:51:46 pm
content: Considering your request, I think that you want to try EasyEDA online design tool, which I found so handy for professionals and beginners, make your own circuit design and then generate your GERBER. last step is the easiest one, drop GERBER to any PCB manufacturer to get quote and place your order, or you can directly place order for your design from EasyEDA and you get your board produced by JLCPCB.I use this combination since 5 years and I con recommend it.

author: james_s
author_rank: Super Contributor
timestamp: May 19, 2021, 04:56:04 pm
content: Creating a PCB layout from a schematic is probably the most labor intensive part of the entire design process. It's something you can do yourself though, just download KiCAD and watch some of the tutorials.

author: tautech
author_rank: Super Contributor
timestamp: May 19, 2021, 05:03:38 pm
content: Big ask to do a power electronics design without some prior PCB CAD experience.Drop Tim (T3sl4co1l) a message and get a quote.https://www.eevblog.com/forum/profile/?u=92330

author: phil from seattle
author_rank: Super Contributor
timestamp: May 19, 2021, 09:24:45 pm
content: Quote from: tautech on May 19, 2021, 05:03:38 pmEven bigger ask when it's a Japanese 1970s era motor controller with lots of discrete and obsolete components. Probably the biggest stumbling block will be sourcing real parts from ebay...

author: jpanhalt
author_rank: Super Contributor
timestamp: May 19, 2021, 09:29:28 pm
content: See: Post #1. TS claims he can source all components. One is left only to wonder, since the BOM posted doesn't define them sufficiently.

author: james_s
author_rank: Super Contributor
timestamp: May 20, 2021, 07:45:07 am
content: He lists ebay links to the transistors, I hadn't looked at those earlier but the one I checked is from a seller in China so almost certainly fake. I'm sure there are modern parts that would work, but it's going to take some knowledge to determine what parts.

author: dellsam34
author_rank: Regular Contributor
timestamp: May 20, 2021, 08:23:52 am
content: New capacitors and resistors are available I just use mouser or dg-key, Diodes and transistors I stick with new old stock since matching to new components using data sheets is time consuming, If the old stock item is not as pictured or does not match the description it will be returned at the seller's expense,

author: james_s
author_rank: Super Contributor
timestamp: May 20, 2021, 04:57:49 pm
content: I'm just speaking from experience when I say that the vast majority of obsolete/hard to find semiconductors offered by ebay sellers out of China are fake parts. It is sometimes difficult to prove they are fake and it's a big hassle and time waster. What do you do when you build your circuit and it doesn't work? How will you identify whether the problem is a counterfeit transistor that is actually some other part with different specs, an error in your PCB or an error in the assembly? You can easily waste a LOT more time dealing with those headaches than it takes to compare datasheets and find modern equivalents. Parts like the 2SC945 are easy to sub, but the pinout on those is slightly unusual IIRC.

author: dellsam34
author_rank: Regular Contributor
timestamp: May 20, 2021, 05:19:09 pm
content: I then just troubleshoot the circuit, the transistor that is not outputing the right voltage is the culprit. I know the new generation don't do this on modern gear, They just swap out the faulty board, Back in the day we fixed it this way, follow the service manual, check voltages or signal points with the oscilloscope until the problem is found. But this is a hobby for me and I enjoy doing it, It is a lot of fun and my kids get to learn something.

author: phil from seattle
author_rank: Super Contributor
timestamp: May 20, 2021, 05:20:23 pm
content: Quote from: jpanhalt on May 19, 2021, 09:29:28 pmNote my use of the term "real". I don't believe for a second that 100% of the sources listed will deliver parts that work. Maybe some will. My money would be on less than a quarter of them yield usable parts. Not trying to sling ethnic dirt but those small Chinese shops a pretty well known for pushing fakes.

author: phil from seattle
author_rank: Super Contributor
timestamp: May 20, 2021, 05:45:12 pm
content: Quote from: dellsam34 on May 20, 2021, 05:19:09 pmBut you are skilled/experienced. OP clearly is not. The plan is to copy the original down to the layout. While reasonable and logical on the surface, plenty of us here see lots of newbie pitfalls. Given that a failure point is probably going to be a random fake device who know what else it will kill so even with a correct replacement, there may be other damage to track. Whack-a-mole for newbies - kind of a train wreck.

author: james_s
author_rank: Super Contributor
timestamp: May 20, 2021, 06:09:06 pm
content: Quote from: phil from seattle on May 20, 2021, 05:45:12 pmBut he IS the OP. I'm kind of confused though, he is calling people inexperienced and suggesting we're a bunch of ignorant board swappers, talking like he has the knowledge to troubleshoot these things while asking questions that implies a beginner.I'm not a beginner, I have many years of experience troubleshooting and have designed and/or built more than a few devices and repaired many, many more. I've encountered counterfeit parts on a multitude of occasions and eventually realized it's a fool's errand to buy certain types of parts from ebay sellers. I have directly experienced the wasted time of getting counterfeit parts and the difficulty of diagnosing something newly built with multiple unknowns, and it is NOT trivial. The components don't operate in isolation, everything in the circuit affects everything else. If you have a transistor for example that is not actually the part number printed on it the circuit may work, or it may not, or it may sort of work, but how do you really know whether it's because of an error in your layout, or a solder bridge or bad joint, the wrong value passive installed somewhere, or a transistor that doesn't have quite the right characteristics? It can be harder than it looks, and again speaking from direct experience, most of the hard to find obsolete parts like transistors and op-amps that are available from random ebay sellers are fake. Try to buy a some kind of audiophile op-amp or even something like a TL082 and 99.9% of the time it WILL be fake. You will probably get an op-amp but it will be the cheapest nastiest die packaged and dressed up as a much better part. The same is true of transistors, buy some exotic hard to find vintage part and you'll get something like a clone 2N3904 packaged as something better.I'm not going to argue over it though, you can lead a horse to water but you can't make it drink. Good luck with the project.

author: mariush
author_rank: Super Contributor
timestamp: May 20, 2021, 06:42:34 pm
content: The schematic is so simple you could easily make it on one or two stripboards :https://www.ebay.com/itm/233178305832?hash=item364a829528:g:E9cAAOSwEDde3Bp~If needed, you can tin the traces on the bottom or double them for more current... Just go left to right, maybe align transistors as much as possible to heatsink them (if needed) ....Agree with the others ... don't rely on eBay transistors being genuine, try to find compatible / alternative transistors with current part numbers.

author: dellsam34
author_rank: Regular Contributor
timestamp: May 20, 2021, 06:44:00 pm
content: You guys are taking this the wrong way, I'm just saying modern electronics are hard to troubleshoot and swapping boards is the trend now for hobbyist youngsters (which I failed to mention), I'm not accusing anyone whatsoever who does this for a living?Where did I say I will not get fake parts? I said it will be returned to the seller at his own expense and I did numerous times where those Chinese sellers ended up loosing the part and not having to claim it back, I've been using ebay since 2004 and I know how to deal with those sellers.

author: dellsam34
author_rank: Regular Contributor
timestamp: June 06, 2021, 09:19:54 pm
content: I have a question regarding Zener Diodes, For the WZ-120 (500mW, Vz 12V, Iz 5mA) and HZ22-3 (500mW, Iz 22V, Iz 2mA) I could not find a match current I can only match the wattage and voltage, Will it be a problem if the maximum current rating is higher for the equivalent diodes? Lets say 20mA instead of the original 5mA and 5.6mA instead of the original 2mA.

author: dellsam34
author_rank: Regular Contributor
timestamp: July 05, 2021, 04:09:08 pm
content: Project completed:

author: mariush
author_rank: Super Contributor
timestamp: July 06, 2021, 03:06:27 pm
content: Seems like a good startI would try to optimize it a bit .. for example try to align those to-220 ICs so they could potentially be placed on a heatsink (with some mica insulators of course) .. maybe even use a SIL bridge rectifier (ex gbu, gbj etc) so it could also be screwed to heatsink with the to-220 chips ... or.... rotate capacitors as needed so the negatives are all in the same direction/side, making it easier to service/repair and harder to manually install some capacitor incorrectly.. align the resistors a bit to make the board look nicer ... maybe consider where possible to reduce different resistor values by getting that value by using two resistors in parallel or series (ex 2 x 10k in parallel gives you 5k which may be close enough to 4.7k so you don't need to have a single 4.7k in the bom)have the bottom as a ground fill or islands of copper attached to the pins of components that get hotAlso could easily get around the need for vias in such project by using wire links / 0 ohm resistors to jump across other traces... no vias could mean cheaper/faster/easier to make pcb as the holes could be drilled or punched out even by a home user

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: July 07, 2021, 02:37:13 pm
content: Keep in mind when ordering the PCB, not sure if yet mentioned:You need to specify the copper thickness. For this, you need to know how much current needs to pass through a given trace. Thicker copper is more expensive (duh), so you don't want to waste money, yet you need enough to get the job done properly. Push come to shove, don't have solder mask applied over the traces and build them up with solder.You can't just copy the trace width of the original w/o knowing the thickness of copper the original PCB uses.

author: dellsam34
author_rank: Regular Contributor
timestamp: July 07, 2021, 08:14:50 pm
content: I did not know how much thickness I needed so I decided to use as wide tracks as possible, It's set to 1.3 mm, And later applied copper all to the ground so it gives it more current flow, Only two mosfets possibly need a heat sink and they are placed at the edges of the board, the others are regular transistors, I chose the footpring of a mosfet to have wider tracks, Autoroute failed with normal footprint so had to do that to get around the problem, The transiostors I got have long legs so I can spread them out.

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2021, 08:26:19 pm
content: Quote from: dellsam34 on July 07, 2021, 08:14:50 pmAuto routing should only be used as a guide to help with component layout !It can be more useful when you have the functional blocks of the circuit configured to help further optimize how those blocks are to be placed, flipped or rotated.Well done PCB's certainly aren't a 5 minute spin.

author: Rat_Patrol
author_rank: Frequent Contributor
timestamp: July 08, 2021, 02:13:49 pm
content: Any reason for the odd sizes of the annular rings?Example: Q13 and Q1 both seem to be TO-220 packages, but the annular ring on Q1 is tiny, while it is fine on Q13. Q1 will be hard to solder by hand.The annular rings for the slide switch on the bottom are also very small, will be very difficult to solder.For hand soldering, you want pads the pads to look like Q13 or D9; a bit meaty. For room constraints, you make them oblong instead of round, such as with Q13.Looking at that board, and the size of the annular rings on the THT components, I would expect that board was intended to be wave soldered.