Questions tagged [pcb-assembly]

The process of mounting electronic components onto a printed circuit board. This can be done manually with a soldering iron, or automatically using a "Pick and Place" machine.

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Is there another component on the pcb that will extend the leg of the component?

In order to realize the event I mentioned in the picture below, I need an auxiliary component. Maybe a component where I can extend one of the holes 5 mm to the side. Or 5mm to 10mm dip adapter. Is ...
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How to connect 2 (and more) PCBs together to make them semi-modular? [closed]

So, I want to design PCBs with some LEDs on them and connect them together. The PCBs are about 2 cm wide and connection has got to be on this sides of the PCBs. I've tried some connectors but ones I ...
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-1 votes
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What's the best way to solder these fine pitched connectors/pins?

During a replacement of a camera mother board, I managed to screw up one of the ribbon connectors, by tearing it right where the ribbon slides into female slot. I am unable to find any replacement ...
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Point-to-point building of medium- frequency circuits, ground plane implementation

I build audio projects and small logic control circuits using point-to-point on perfboard (see pic of a recent build). As you can see this allows me to select wire gauge in accordance to the currents ...
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INA219- I2c bus weird behavior

I have a PCB assembly where I built the circuit in the schematic below. I did not start programming yet. I'm getting the weirdest problem. When I check the voltages in the SDA and SCL lines (which ...
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1 answer
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Reflow soldering with temperature-sensitive components and without a reflow oven

I need to assemble and test a rather large (40x30 cm) board with single sided SMD parts, Sn Ag Cu solder (officially 217°C melting point). Usually I place group after group of components and locally ...
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1 answer
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2 Layer PCBA routing strategy for high current design

I have a very simple pcba design. The only thing of value is that the traces will carry up to 30A of current. I have already decided to increase copper thickness to 2 oz for improved current capacity. ...
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4 votes
4 answers
503 views

Is there any difference between Silicone and RTV

I've used silicone RTV that's intended for use on PCBs and have also used 100% silicone purchased from the hardware store to use on PCBs. I was not able to tell a difference between the two. ...
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15 votes
5 answers
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Can extra long pads cause problems?

I am a hobbyist and I find it very difficult to solder and work with SMD components which have very small underneath pads. I can't see when the solder flows, I can't touch the pads with the multimeter,...
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3 votes
1 answer
278 views

Will layer-to-layer leakage happen in a PCB?

I have a four-layer PCB that contains a circuit that measures voltage from a very high impedance node. This voltage is a DC voltage value ranges from 33 V to 36 V. The voltage measurement circuitry is ...
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3 votes
1 answer
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Question regarding durability of wire to board contact

I am designing a board that has to carry up to 32 A of continuous current through it, and as such I need a cheap and compact method of permanently mating the 6 mm² wire to the PCB. Since I have very ...
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Homemade double sided PCBs and soldering

I etched my own double sided PCBs (no plated through holes) and quickly realized that there will be an issue with making sure contacts on both sides of the board are making a proper connection with ...
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3 answers
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SMD 0402 resistor flipped on its side

I received some boards back from the PCBA fab and noticed that one 0402 resistor is flipped onto its side (R25): This site tells me this is a pick-and-place error. But the footprint happens to be one ...
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9 votes
7 answers
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How to solder a stranded wire to a THT hole of a PCB as shock-resistant as possible

I'd like to solder several stranded wires of a cable (maximum 18 VDC) to a PCB. I've got corresponding THT holes (⌀ 0.8 mm; it's the eight holes underneath the yellow wire,) but the wire is thicker (⌀ ...
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2 answers
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Help in finding articles/research papers regarding materials used for designing small PCBs

I am currently working on an article for my internship on the topic of techniques for PCB design under space constraints. I am looking for the type of PCB materials that are used for manufacturing ...
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1 answer
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How to outline traces in graphics

I've been searching online with no luck. I'm using KiCad and I want to outline my traces with graphics similar to the image shown below. Is there a function within KiCad that does this or is this a ...
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How to solder high amperage PCB wire lugs

My concerns are how to successfully hand solder a double-sided, 4oz copper PCB. The plated-through holes in the board have no thermal reliefs and are attached to the power and ground planes. The board ...
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Aligned vs not-aligned components: Which is better for PCBA process?

I am designing a Raspberry Pi hat PCB for a home automation control project. It contains many SMD resistors and capacitors. I was just wondering if aligned components have any benefit over not-aligned ...
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4 answers
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SMD, reflow or hot-air gun?

What are the advantages and disadvantages of using a reflow oven vs a hot air station for prototyping SMD PCB? Do you need an oven or would an air station work?
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1 vote
1 answer
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Soldermask bridge gap too small - PCBWAY

I've got a PCB design which contains a chip that uses the QFN (7x7) package. Because of the package size the pins are very close together and the pads are 0.2mm apart, which is smaller than the ...
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3 votes
1 answer
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Selecting larger inductors than necessary for cost optimization

I'm designing a board that I want to initially manufacture using JLCPCB for both the board fabrication and assembly. The pricing approach at JLCPCB separates available components into commonly used &...
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-1 votes
2 answers
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What is wrong on this circuit? LDO Regulator TPS74401

I'm testing a board that I designed. I'm measuring all the input pins from LDO Regulator TPS74401, and all of them are ok (3.2 V). With my schematic configuration, the output should be 1.1V but the ...
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1 answer
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JLCPCB Bom Detection from U

I am trying to order a PCB from JLCPCB and have the following problem: When I enter the BOM in the Assembly it does not detect U1, all the other components are detected. What could be the mistake? ...
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Have there been any significant industry-wide changes to PCB manufacture in the last several years (~2019-2021)? [closed]

Sorry for the naive question! I want it to be specific enough to be answerable, but I'm not sure how to find the answer to my actual question, so I'm asking it here. Another way to put it might be &...
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3 votes
2 answers
345 views

Solder bridge pad spacing and scratch trace width

To save cost on a board I'm designing, I'm considering replacing an 8x2 male pin header intended for jumpers (which previously replaced an 8-position DIP switch) with 8 pairs of rectangular solder ...
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2 answers
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Can I leave a throughole pad off one side of a machine-fabricated PCB?

So I'm designing a two-layer PCB and I'm very inexperienced. A third-party company will fabricate them. Now, I have a PTH part with a number of closely spaced pins (and there is no SMD equivalent of ...
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183 views

Soldering wire directly to a PCB through hole vias, what is acceptable proximity tolerance?

The wire gauge is 16 AWG. The hole size is 63 mil, and the overall via diameter is 98.5 mil. What is the minimum spacing between two of these for voltage levels of 0-12V and 0-160V circuits? I think I ...
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7 votes
2 answers
1k views

How do PCB manufacturers know how to orient polarized components?

Let's say I have diode or a polarized capacitor in my circuit. How do PCB manufacturers know how to orient the part on the PCB? When I create the part in Altium for example, I just make up which pin ...
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1 answer
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Split / combine a larger printed circuit board from smaller boards

I have plans for a large PCB (~12".) Some sections of this board are modular - they have a very similar design. To lower the price, is it feasible to split one big board into smaller, modular ...
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1 answer
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SMT PCBA production

I am interested in setting up an SMT factory for producing PCBA. I have researched and know the whole assembly process such as solder paste application, reflow oven, etc. Regarding the packaging of ...
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1 answer
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Thermal vias-in-pad - leave bottom side tented or exposed?

What is the suggestion for thermal vias under the exposed pad of ICs ? I understand that copper plugging would be ideal. But if I only have the choice of tenting or not tenting, should I leave the ...
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1 vote
2 answers
152 views

0805 package SMT pads minimum clearance and tombstoning

The picture shows 0805 LEDs and one last 0805 resistor connected to the GND pour. What is the minimum clearance between the SMT pads of the different 0805 LEDs that I should consider safe for ...
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11 votes
5 answers
2k views

Does the PCB have to be thinner than through-hole pin length?

If I have a part that has pins that are 1.2mm long. Can I use a PCB that is 1.2mm thick or does it need to be even thinner than that?
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2 votes
3 answers
387 views

How do I get pin headers to reflow flat to the board?

I work for a small company as an apprentice. We build mostly mass produce double sided PCBs. We are having trouble keeping the pin headers flat to the PCB through the reflow oven process. The first ...
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1 answer
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My PCB design doesn't work when put together

I created the PCB based on the schematic shown below. I ordered the PCB shown below that I designed and I connected up. After I soldered all my parts into it and connected a 9V battery, nothing ...
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8 votes
5 answers
3k views

How can I remove the solder bridges?

I assembled this PCB using the SMD reflow process (I used the oven/toaster for heating step.) I am not sure why, but there there are solder bridges that have been formed on the MCU's pads. The ...
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2 answers
66 views

If a PCB is inspected to an IPC-A-600 class higher than specified what are the negative impacts?

I have received several parts from a PCB manufacturer which should have been inspected to IPC-A-600 Class 2 but were instead inspected to IPC-A-600 Class 3. I believe I have received PCBs inspected to ...
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2 votes
2 answers
132 views

What are the standards for hand placing components?

Is there any written specification for the orientation of components on a manually assembled PCB, including both THT and SMT passive components? 'Manually' because machines can be easily setup to ...
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0 votes
1 answer
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I2C interface frozen until reflowed again

I have custom PCB with nRF52832 MCU and two I2C devices sharing same bus, IAM20380 on 0x68 and IAM20381 on 0x69. All works fine, but after a few hours of testing I2C interface freezes when I2C command ...
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8 votes
2 answers
729 views

Drill through PCB or just use glue to mount component?

For a one-off hobby project I want to add a potentiometer to an existing two-sided PCB. There is an unpopulated zone (as far as I can tell) on the PCB that looks ideal, but I'd have to drill mounting ...
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1 answer
65 views

Circuit Board Troubleshooting [closed]

The question is: "Where can I get circuit boards tested or troubleshot?" As My profile shows, I am not an EE, but I'm forced to play one at my company. The following is just some background ...
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2 votes
1 answer
104 views

How do I find the center of a part when making a footprint for a component that will be used in a centroid file?

Often the footprint I need is not in the existing libraries and I need to make my own. For example one of the dozens of micro USB footprints. When I make a footprint and then send for assembly at ...
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1 vote
1 answer
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PLM management and PCBA numbering strategies [closed]

I was wondering if people here have their own ways of board numbering and how they keep a track of it? For e.g Unique Number-Revision Number-Board Description. I have used team centre in the past to ...
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  • 539
7 votes
5 answers
1k views

Question about assembly with DIP packages

I'm sending a board for assembly with a through-hole DIP-8 package with a standard horizontal lead spacing of 7.62mm. However, at their ends the pins are wide with a pin spacing of ~8.47mm. Should I ...
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Using ground plane between components on top and bottom layer

I’ve recently been reviewing some PCB designs to learn good practices. One thing I’ve seen is that a ground plane is used on top layer between the components and traces. Is this a good practice and ...
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6 votes
1 answer
201 views

Why do I have shorts/bridges on QFN packages on PCBA during assembly? Stencil Printing problem

I am trying to do a home assembly of PCB but I have issues after reflow soldering. Especially I have bridges/shorts on the pins of QFN packages. I have assembled multiple boards other joins are okay ...
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0 votes
1 answer
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Cement Power Resistor PCB Mounting in Vibratory Environment

I'm looking to use a cement type wirewound power resistor on a PCB. We need the short term peak power capabilities that this type seems to provide. It seems the most common are thru hole type, like ...
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0 votes
2 answers
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TMUX1119 SC70 package first pin identification

I have a TMUX1119 with an SC70 package. The datasheet says there is a dot near the first pin. The actual device that was received is shown below. I can see a line and below it is written 1DF. Which is ...
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0 votes
2 answers
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Recreating Arduino UNO - PCB design (How are the components connected?)

I'm trying to recreate the Arduino UNO in order to be good at PCB design via EasyEDA or Altium. I have recreated the Arduino Uno schematic and design but it is hard for me to figure out few things (...
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How to join VBUS lines on a PCB Design

I'm making a little PCB for a USB-C to USB-A Legacy, the same PCB which is used on the cables, but I want to use a FFC cable instead USB A connector. I'm using USB-C to USB-A Legacy recommendations ...
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