59

Take the best pictures of both sides of the board that you can. You can use a scanner to scan the bottom side of the board, but not all scanners will be able to focus the top layer because of the height of the components. To this guide I used a 3MP camera of the iPhone 3GS without any special lighting or anything. You will almost always likely to ...


40

I have two possible explanations: The 'knuckles' are there intentionally to avoid the pins going all the way through the PCB. Most of the times it is not desired that the pins are going all the way through the PCB. They are a remnant of the production process (see picture below). First the pins are a part of one single metal sheet and are cut after the dies ...


26

You need the pin or wire to be able to fit thru the hole, but otherwise tighter is better. First, you look at the specs from your board house. They will give you the tolerance of final finished hole diameters from what you specify. In some cases, they will round to the nearest drill size, with then a resulting diameter range for each such drill. In other ...


24

This is a one-off prototype, so doesn't need to withstand end-user mechanical abuse. I would probably trim the leads a bit, then set the ends of the leads on the pads, using the holes to align them. Now use solder blobs to hold the component in place. The leads aren't going through the holes, but the ends are sitting on top of them. The solder guarantees ...


22

It's an adjustable inductor and probably used at VHF: - Also available in other colours: - And in other styles: - Some with screen cans: - And some come with an internal capacitor and that makes it sometimes difficult to identify: -


22

Decades ago there were clamping systems available. Components were mounted on the top side, a sheet of board-backed foam pressed down on the stuffed board and a frame clamped the whole lot together prior to turning upside down. Figure 1. A solution from Nuts and Volts. As usual, you'll probably need to do the low-profile components in the first pass and the ...


21

PCB size is not the only cost consideration and you need to consider recurring costs vs. one time (non-recurring) costs (some of the non-recurring may actually occur more than once for a 50k run). Note that using double sided techniques rarely (if ever) yield a PCB half the size of a single sided part - in my experience you may get one that is perhaps 40% ...


18

The round pin headers (also known as "machine pin headers") typically provide a more secure fit, with more contact surface area between the pins and sockets. They are often used in applications where vibration is a problem. They're not used universally, because the machining process makes them significantly more expensive to manufacture than the ...


18

I routinely salvage through-hole and even SMD parts, with the following considerations: 1) If the device is broken, the components from it are suspect; check everything. I have one of these which is invaluable (It tests more than transistors). 2) If the leads are not long enough to go into a breadboard, it's probably not worth it. I find that most ...


18

The hole for the connector would be near the center of the MCU package, away from the pins. This is a very bad idea. Usually the pins from through-hole parts stick through the board by at least a millimeter, more than enough to interfere with the ability to place a chip where it would cover the pin. You could conceivably cut the pin short enough that it ...


18

That is an adjustable inductor with a brass slug. Turning the slug out of the coil will raise the inductance. Turning it in will reduce the inductance. This is the opposite of the more typical variable inductors that have ferrite cores. Ferrite cores are the black ones like in the examples that Andy aka posted. Given the low number of loops in the coil ...


18

It’s just a quick and easy way to distinguish which connector pad is pin 1. Particularly when there is no silkscreen present or just when routing the PCB.


17

Insert all the components of the same height. Maybe you have a holder to hold the board steady and off the bench. Put a piece of material (wood, heavy cardboard, foamcore) on the top of the board and flip it. Solder all the parts in and trim the leads. Repeat for taller parts. If you have a 3D printer or a milling machine you can easily make a jig that will ...


16

Low low low cost is the aim. A small volume maker with no expertise in anything other than manual soldering (if that) can make these. They can be even made at home by workers if desired. Single side phenolic board. Cheap. Not only manual assembly but component size and hole spacings not well matched and leads are hand bent and nobody cares. A design ...


16

That's a DIP switch array, just that the switches don't move left or right, but up or down. The component visually resembles a (musical) keyboard, hence the name. If you have a current version of kicad, try the 3D viewer (there's a button for that in your window). You'll see the component in 3D!


14

One of the key points to answer your question is thermal stress. When you apply heat to one pin of a device, there is a suden and huge temperature difference between that point and the rest of the device. That difference is stress, and the result can be a material breakout. On an oven, on the other hand, all the board is put under a controlled, gradual ...


13

May I present the LT1761 regulator circuit complete with recommended capacitors on inputs and outputs: - On your PCB design I see only a 10 nF capacitor. I also don't see a device footprint that matches the footprints shown in the data sheet but I could be mistaken about this. Looking at the circuit you have linked.... Try and learn to use vias and be ...


11

For most through-hole parts, I specify .035" finished hole size. This is suitable for DIP ICs, 1/4 watt resistors, small transistor and capacitors. .040" is needed for post headers, and larger holes are required for TO-220 transistors, larger diodes and electrolytic capacitors. The 7 to 15 mil oversize suggested sounds reasonable to me. If you are using ...


11

TO-92 and similar types of through-hole transistor packages are not that temperature sensitive. They're soldered by running the bottom of the PCB over a fast-flowing river of molten solder which transfers heat rather quickly. The boards are typically preheated a bit, but only to about 100°C. Here is a video of wave soldering. The vapor you see coming off ...


11

Both approaches are valid. Hand assembly would require that the paste mask for the SMT devices prevents putting any paste on the thru-hole pads at all. Then you use wire solder as usual during the hand assembly phase. Thru-hole devices can be soldered in the reflow oven; this requires a technique called "paste-in-hole" — but it doesn't work with all ...


10

It depends on your design but if I wanted use a design for high frequencies, I used through hole just for power/heating parts and used SMD for the rest because SMD design can reduce inductance and resistance of component parts . Advantages of SMD: 1-Smaller components. 2- Much higher component density (components per unit area) and many more connections ...


10

Those particular leads in the photo do not look like they're intended to stop the part from going down as far as you like. Are you sure you used the recommended hole size in the datasheet? Or did you just take the nominal dimension and use that.. I would expect the recommended size to be relatively large for such an item. Get a set of these generic Chinese-...


10

You could trim the leads short, and solder thinner solid wire to the stub leads. If you want good reliability, you should wind one end of the thinner wire on the stub leads or a slightly oversize mandrel, as if you were winding a spring. This will provide an order of magnitude larger stressed area for the solder, leading to a much more resilient joint.


10

Mass production THT parts are either done with cheap people, or with axial insertion machines. You can find lots of videos on youtube: https://www.youtube.com/watch?v=CCBST-qk2t8 https://www.youtube.com/watch?v=P17J5RzbsgQ They pull the part off the bandolier, cut the leads, bend the leads, insert the part, and bend the leads on the opposite side in one ...


9

It isn't a solution to all through hole components, but for devices with more than two pins I've taken to designing my landing pads with hand assembly in mind. For instance, with header, the pins can be slightly offset so the pins fit snuggly in the PCB, like this: Each through hole has an alternating plus or minus 0.05 mm offset from the center (it's a 1....


9

The answer is a resounding yes or maybe. Yes salvage what you are likely to use in some way for play, study or repairs and maybe don't keep stuff that you will never use. I find that keeping a couple of old and a couple of contemporary PCBs of the sort that I am likely to work on or experiment with saves a LOT of time compared to ordering or shopping for ...


9

The best way to place decoupling capacitors is to visualize the current loop that your IC will create. The purpose of the bypass cap is to shorten this loop. (Illustration borrowed from Macrofab). The current doesn't really care whether it's traveling through a plane or a trace. All that matters is the loop length. Keep it short and you'll be fine. You ...


9

They are called "castellations", from their similarity to the battlements of castles. An example explanation from seeedstudio.


8

In the IPC 7251 it is documented that: Hole Diameter = Max Lead diameter plus the level value (Min 0.15 - Max 0.25) On the PCB-3D website they added some extra info: Minimum Hole Size is calculated according to equations below: Minimum Hole Size = Maximum Lead Diameter + 0.25mm (for Level A of IPC-2222) Minimum Hole Size = Maximum Lead Diameter + 0.20mm (...


8

Blu-Tack/Fun-Tak works. It's a removable adhesive putty. Think post-it note glue. Sticks well but easily removed. Can easily hold things in place upside down.


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