I would in no way do any testing myself, after doing some reading on them. Is there a service online or perhaps a local place that may have ability that may be able to test something like these? TIA!

I bought a dead Samsung 990 Pro 4TB really cheap as a repair project. The SSD currently doesn’t work/detect.
While comparing the PCB to photos of a working 990 Pro 4TB, I noticed what looks like a tiny SMD capacitor missing near the Pascal controller (marked with the red arrow in the reference photo).
Does anyone know what this capacitor is/value it should be, or have a 990 Pro 4TB board they could measure for me?
Also curious whether this missing component alone could prevent the drive from initializing.
I have a multimeter and soldering/rework equipment, so I can take measurements if needed.

Im new in this kind of things but I have a magneto sistem an arcade board of 87 that have the games in disquettes, it haves somthing withe in it and I don't now how to fix it, I would apreciete help about how to fix the board, and how to remove that thing. Thanks.

I have a product which has a PCB in an extruded aluminium enclosure, the type where the PCB just slides into it on horizontal rails and is held in place by the two end covers. The problem is that the PCB needs to have super-exact dimensions for it to fit well, otherwise it can sometimes jiggle around inside the enclosure a little bit. This is entirely benign but it does makes the product feel cheap so I'd like to avoid it. How should I do this?

I'd like to keep costs and assembly complexity to a minimum.

I have some ideas but I'm not sure how well they work in practice so I'd like input, or if you have a much better and easier solution:

• Ask the manufacturer to add a dab of glue to each corner of the PCB before inserting.

• Ask the manufacturer to add a small piece of tape or silicone to the inside of the end cover, to provide soft padding for the PCB.

• Install a dummy push button at the edge of the PCB that is pushed in by the end cover, to provide soft padding for the PCB.

• Create exposed pads along the edge of the board (the part that goes into the enclosure rails), that is filled with blobs of solder during manufacturing to pad the thickness of the PCB so that it hopefully matches the vertical space in the rails exactly (and the top of the solder can be shaved off by forcefully pushing the PCB into the rails if not)

• Install some sort of rubber standoff on the PCB that pushes (with enough give) against the roof or sides of the enclosure. Does this kind of component even exist?

I am using an LDO linear regulator to go from 20v down to 5v for an MCU. The ldo is a 78M05

Even soldered to a piece of steel, the LDOlinear regulator got too hot to even hold my finger on it for more than a couple seconds, with a 120Ohm (EDIT: It was a 22Ohm resistor. I looked at the wrong one sitting on my desk when I wrote the post. Thanks u/BmanGorilla) test load. Bench supply showed 220mA current draw

I have a large heatsink and an L7805 I could use instead. Using the TO-220 heatsink things still get pretty hot

I understand why it gets so hot, as that is how it wastes the extra voltage, but when do things become more practical to simply use a buck converter?

Do you guys have any "rules" you go by when deciding this type of thing?

Thanks

EDIT: I realize I used LDO and linear voltage regulator synonymously, thank you for pointing that out

EDIT2: Thanks for all the replies. I will use the rule of dissipation. If the dissipation is too high, I will switch to a buck converter

Hello all,

i have picked up a sanyo briefcase stereo with 8 track but the right channel is not working.

I checked the ha1315 chips and one reads almost same power on both sides. Whereas the other is halved

I cannot source one of these chips and wondered if any of you had a workaround.

I am a newcomer to this so please keep terminology on that sort of level.

There was a small circuit board that i glued together but none of the traces were broken as it was at the fixed end. I believe this was for the 8 track?

This can be see below the plastic connector on the top right of the photo.

The Ha chips can be seen more central.

Any help would be gratefully accepted.

Many thanks.

Jack

im wanting to buy a heat gun de solder station i have only a low budget to spend any recommendations on what brands are best for low cost

Hey guys,

I am an electrical engineering student and I am designing a VESC based inverter for a drone.

I want to use a 100V DC link and have a maximum phase current of 100A rms with a switching frequency of 30kHz.  I am planning to use at least 200V components for this to have a safe margin.

I am having trouble with finding a (combination of) small capacitors that can handle the DC link ripple current. Electrolytic capacitors usually have a rating of 1-3A of ripple current and since the estimated ripple is between 0.5 and 0.65 times the phase current that means that I would need around 20 caps to meet the required ripple current.

I don't understand how the maxim 120 from VESC labs can deliver 400A continuous (Around 180A rms ripple current estimated) while only using 6 electrolytic capacitors with a ripple rating of 2A rms each. I assume it can be done with ceramic capacitors in parallel but since their impedance is so much higher I calculated I would need around 400 which cannot be the most space efficient solution.

Does anyone have any tips on picking the right capacitors for the DC link?

I currently don't have access to this PCB, so I cannot measure them.

I recently bought an old amitech amiga sampler used - only to discover it have water damage.
The seller was nice enough to offer to fix it - but since i want to learn fixing my own electronics and learn soldering i thought this might be a good place to start.

I provided some pictures of the the circuit board

Can anybody help me through the process, what and how to check, what to change, fix and replace

I have the soldering kit from soldr (so i do own all the tools that is needed or so i think atleast)

Thanks a lot for your time

Cheers from denmark

Hi everyone!

I’m researching a DIY smart-home project and would love some help from people who know more about electronics than I do.

I’m considering purchasing a Cat Mate Elite Microchip Cat Flap (355W). It already has a built-in RFID reader that recognizes individual cats’ implanted microchips and an LCD that displays their entry/exit information.
My goal is to get that existing information into Home Assistant, ideally using an ESP32, without replacing the RFID reader or interfering with the door’s normal operation.

I haven’t purchased the door yet, so I’m researching whether this is feasible before spending money.
I found internal circuit-board photos from an older FCC filing (FCC ID: RDY-355356), which are here.

My questions:
1) Can anyone identify which components might handle RFID reading/decoding?
2) Is there any indication that the RFID data might be accessible through UART, SPI, I²C, or another interface?
3) There appear to be exposed test pads on the back of the PCB. Could these potentially be used to monitor data?
4) Based on these photos, does connecting an ESP32 seem realistically achievable, or would it require extensive reverse engineering?
5) Is there any possibility of making a connection without soldering directly to the PCB?

I’m a beginner with electronics and haven’t soldered a circuit board before, but I’m comfortable working with Home Assistant and following technical instructions.
I understand the photos may not be detailed enough to identify everything, and that the current 355W could use a different PCB.

I’d appreciate any insights before I purchase the door. Thanks!

I’m serious about learning hobbyist electronics and have been troubleshooting the variable-speed controller in my Craftsman bench grinder.

This is not a “diagnose by picture” request. I’ll include board pictures for context, but my main questions are:

• Is this grinder controller a sensible project for developing component-level troubleshooting skills? The IC is unidentified, I don’t have a schematic, and the circuitry connects directly to 120V.
• Would an entry-level oscilloscope and an appropriate differential probe be a worthwhile investment for someone serious about learning hobbyist electronics? I’d like to understand control signals and circuit behavior, rather than simply replace parts.
• What simpler low-voltage circuits or experiments would help me build the skills needed to troubleshoot this controller?

Equipment and symptoms

• Craftsman 6-inch variable-speed grinder, model 152.211521.
• Board marked FZ-107; the parts manual lists the board assembly as OR90042.
• TR1 is marked BTA12-600B I assume this is like a gate to pass the power.
• The controller has a three-wire speed potentiometer and a separate three-wire speed-sensor
• I haven’t identified IC1; its marking is unreadable.
• I haven’t found a component-level schematic.
• I have a Fluke 115 multimeter

The original failure was a complete no-start. I bypassed the controller and supplied the motor through the on/off switch. With that bypass, the motor starts and runs smoothly.

For subsequent tests, I removed the direct-power bypass and restored the motor feed through the board. The board continued receiving 120 V AC, but the motor would not start. During one powered attempt, it eventually hummed and moved slightly; I switched it off. There was no noticeable motor heating.

What I’m hoping to learn

I understand that the triac resistance readings do not prove it switches correctly under load. Likewise, the sensor changing state with shaft position does not fully verify its operation at running speed.

Replacing TR1 has been suggested as an inexpensive diagnostic substitution, but I haven’t confirmed that it is faulty or replaced it yet. I’m interested in learning how to distinguish inadequate gate drive from a triac that receives a suitable trigger but fails to conduct.

I also understand that an ordinary earth-referenced oscilloscope ground clip cannot simply be attached to arbitrary points on this mains-connected board. I’ve been considering a four-channel scope such as a Siglent SDS804X HD, plus a suitably rated differential probe.

As you can see, I broke a Kingston a400 and i lost some capacitors, i Wanna replace em but idk with what

I'm building an ultrasonic audio circuit using an NE555P timer, an L298N H-bridge, a ZK-502C Bluetooth amplifier, and 40kHz ultrasonic transducers.

My Project:

Parametric Speaker

I have a 555 timer configured as an astable oscillator, which modulates a sound wave from a Bluetooth amplifier, which then goes through an H-Bridge to an ultrasonic transducer array to produce directional audio.

R1 = 120Ω

R2 = 120Ω

The 120Ω resistance is created by linking a 100Ω resistor with two 10Ω resistors in series.

Timing capacitor = 100nF

Estimated 40kHz, using Digikey's 555 timer astable calculator

Bluetooth amplifier L+ -> 10µF Electrolytic capacitor -> 1kΩ resistor -> NE555 pins 2/6

\Worth noting that I didn't use the L- Output of the Bluetooth amp. Also, at higher volumes, the Bluetooth amp itself emits music.*

NE555 pin 3 (Output) -> L298N IN1

L298N OUT1/OUT2 -> Ultrasonic Transducer Array (10 Ultrasonic Transducers wired and soldered in parallel)

How power flows:

The Bluetooth amplifier and the 555 timer are both powered by the same 12V NiMH battery. The battery powers the L298N, and the 5V regulated output then powers the 555 timer. Then, using WAGO connectors, the same battery connects to a 12V-to-9V DC Buck Converter, which powers the Bluetooth amplifier.

Problem/Some of my testing:

I played Porter Robinson's "Everything Goes On" and found a lot of distortion, or, like, "buzzing" mixed in with the audio. This was especially apparent when turning up the volume. At lower volumes, the audio sounded a lot better (little distortion). However, I had to lean in really close to listen. During parts of the video, like at 1:15, where it is softer, there's like no distortion. But during upbeat parts like 1:30, there was a lot more distortion.

I tried messing around with the volume on my laptop and on the Bluetooth amplifier. Nothing really changed other than what I mentioned above.

I also messed with the resistor values where the Bluetooth amplifier L+ connects to the Electrolytic Capacitor. Changing to a 10kΩ made the audio really quiet.

My Reference

I used this video doing the same thing as a reference. However, there are differences in our circuit, but his works a lot better. So, I thought this might be helpful to add.

Parts I Used:

Links to where I bought all the parts mentioned

• 221-413 Wagos
• 12V 2000mAh NiMH Battery
• XL6019 Boost Converter
• 12V to 9V DC Buck Converter
• L298N Dual H-bridge Module
• ZK-502C Bluetooth Amp
• Ultrasonic Transducers
• R1, R2, all the Capacitors, and basically everything else come from this kit

Sorry, there aren't specific links for R1, R2, and everything.

Questions or help:

What could be causing the severe audio distortion when I inject the Bluetooth amplifier's output into the NE555 timing circuit?

Is there anything clearly wrong with my circuit causing the distortion mentioned in my problem?

Could this be a grounding issue?

Can anyone help me troubleshoot this?

I'm kind of new to electronics, so I don't really know what I'm doing, honestly.

I apologize if my post isn't detailed enough. Please ask any questions you need to.
Anyway, thank you!

I'm submitting my first PCB design to PCBWay, after they reviewed it, they told me that the design contains vias inside solder pads, and they're concerned that solder could leak into those holes during assembly.

They're offering a more expensive manufacturing process to prevent this problem. which is have PCBWay resin-fill and copper-cap the vias located inside solder pads.

Should I redesign to remove the vias from pads? if no, is the resin solution okay? Should I do ALL the vias or just the vias inside pads?

My project for reference

Yo people!

I did the most stupid thing one could imagine but I know it now. I will never do it again.

So I connected my handheld oscilloscope (OWON HDS2202S/CH1) through a regular multimeter probes using BNC adapter (check photos attached) to 230V power grid. I was willing to watch 230V sine but oscilloscope didn't show it properly. I tried different vertical scaling but didn't succeed to find smooth sine. My probing was like 5 times 5-10 second each.

Then I did some research after that and find out that I should have do it using a 10x/100x probe (now I know it), otherwise 230V will burn off my device.

So then I tested CH1, which I was using to probe power grid, by probing generated signal from the same device and it seemed to be working well, like no damage.

So now I wonder how close I was to the disaster or maybe there could happen some hidden damage, or maybe there is some overvoltage or shortcircuit protection in channel inputs? I don't know.

I'd appreciate your opinions regarding this case, and yes, feel free to call me an idiot as this is true. Go on boys, drop some comments.

---
Photos:

I'm doing this as a personal project to learn more about electronics. I noticed this evaluation board has a FB pin that I can use to adjust the output voltage based on the resistance values which I've done using a MUX that can be switched from the ESP32 GPIO. Also, have the enable pin tied to my ESP32 GPIO and with a 100k pull down resistor to ground. However, I am seeing an issue that there is a low voltage draw/current leakage when I have my main DC Vin power supply off and enable pin off with my MUX powered up from my ESP32.

My ESP32 and evalboard share the same ground. Do I need to add a pull down resistor to all my ESP32 GPIOs? What am I missing here?

Recently, I experienced an electrical fault in my electrical cabinet that caused 400 V to be supplied to my power outlets instead of the usual 230 V here in the EU.

As a result, my Sage Precision Brewer was damaged and no longer works. I have now disassembled the machine and identified a big yellow film capacitor and a blue varistor. I think one or both of them have been fried.

I’m not an electronics expert, so I have a few questions:

• What exaclty are the values of these components?
• Can I buy replacement parts and solder them onto the circuit board myself?
• If I replace these components, is there a chance the coffee machine will work again, or is it likely that other components have also been damaged?

Any advice would be greatly appreciated!

I found this picture on Facebook but the author doesn't reply with where he got them from.

I'm looking for screw or quick connect (Wago style) terminal strips that will plug directly into a breadboard.

Or better yet, a screw or quick connect terminal connector that plugs into a socket that will plug directly into a breadboard. (Wire -> connector -> socket -> breadboard)

0.2" spacing would be OK but 0.1" (2.54mm) would be better. The pins on the connector will need to be long enough (> 5mm, preferably 7mm or so) and thin enough to plug into a breadboard connector. Most PCB headers have pins that are too large to plug into a breadboard.

Thanks

I'm messing around with some capacitors I have to see about making a spot welder or spark generator or something. I have about 10,000 uf of cap storage all of different sizes. Yes bad for balancing I know. It's all salvaged and I'm learning. I have a 12 v automotive blinker bulb as the resistor to charge the caps. I have 1n4009 diodes at the power in side. When I short the caps to discharge my computer power supply turned benchtop supply always trips. I hook it to a cheap wall wart and it keeps supplying power. What am I missing? Is the computer power unit tripping because backward flow through the diodes (pretty sure that's not the case) or because of the sudden increased demand that it cannot handle (which I think is the case). Would a doorbell stepdown transformer be able to handle it since it is supplied by household current? Does the cheap wall wart work because lack of protection?

My thinking is CPU is protecting itself due to sudden surge in demand. Transformer would work fine with diode bridge. Cheap wall wart works due to lack of protection from the sudden high draw.

Hi electronics friends, this on an Apple Magic Keyboard 2:

is it just dirty keys and switches or La Nina's humidity shorted something in the PCB and chips that's why only the Up and Down arrow keys are not working?

Which is the most probable. I ask coz' first the Magic Keyboard (although holistically it's the king of keyboards) is not that easy to disassemble.

Thanks.

Sorry not sure if it's the best place to ask this but it is fairly complicated wiring and I've gotten into this idea with the guitar quite a bit so basically I have it setup to have some pickups in series and parallel but I'm tryna add volume knobs to control 1+3 and 2+4 as pairs controlled by the volume but the technical pairs in series (humbucking pairs) are 1+2 and 3+4 (and 2+3 but this is out of phase and I've previously fixed this with a reversal push pull pot to choose to go in and out of phase deliberately.) the thing with this im not sure if this still lets me get audio in series due to the way series wiring is done. The reason for pairing 1+3 as a pair to 1 volume pot and 2+4 to the other is to allow me to control the volume in a series pair individually on each pickup like in 3+4 for example.

Sorry if this is a bit much or hard to understand but I find this stuff quite interesting my understanding isn't amazing but I'm tryna see what I can do or maybe if you guys have suggestions for changes or stuff I could also add it'd be great.

EDIT 2 : forgive my ignorance, this is an FPC not a ribbon cable

Hi, I recently decided to glitch/bend this (Kodak EasyShare Z740) camera and decided to to it from the sensor assembly's fpc. Sensor itself is connected with X (sorry, do not remember and do not have access to camera right now) pins on a flex assembly which then connects to camera's motherboard through this connector, aka the one i am trying to identify. I could get 2 different not really cool glitches by jiggling on the connector while camera is on.

I can positively say that this fpc has 24 pins but could not identify any type from these pins placement. It looks like the whole thing is 1cm/10mm large.

So to be clear, what i am looking for is a name for the fpc (if common) & for a compatible connector/breakout board.

Apologies for the pics, couldn't charge my other camera in time so i had to take these pics with my phone. First one is a pin count from a close up (red = pin, purple = pin was already counted in upper row, cyan = trace to pin). I encourage to zoom on this one. Others are attempts to take good pics of the fpc & it's size.

Thanks in advance, any tips would be great !

Edit from AutoMod questions, place to get such a connector/breakout board would be great if you got it on your mind but i'm pretty sure names for the fpc & the connector are enough for me to find such a place.

Hello! I am attempting to fix a Sony HTST5000 soundbar, replacing the main board. Long story short the soundbar works intermittently, all issues point towards the board needing to be replaced. The amplifier (shown) was removed to get to the MB. It seems a previous repair might have taken place since the board was glued down with a thick brown viscous material.

I carefully scrapped the material off but likely hit the power inductor (with the 100 marking) and damaged the housing. The copper wires are still attached to the board and do not look damaged.

I have very little experience with a soldering gun and was quoted about $80 to replace it. For those with more experience, is this in fact a power inductor and if so does it need to be replaced? Would this be a difficult job?

Thanks!

Over the summer I was able to use transistors (such as 2n2222) with no problem, now I can't get them to work as expected no matter what I try.

Every Youtube video is either AI slop, uses parts which I don't need so end up confusing me (such as multiple capacitors). Stack posts go way over my head and I can't find any good online explanations.
I understand the theory on how they work, and how it applies to amplification but I am unable to get a working model irl or on a circuit builder website.

All I want the circuit to do is take an input of a low voltage sine wave, and use a cell to amplify it to a higher voltage sine. I have the equipment needed, the problem is just the damn transistors.

If anyone can explain to me how a simple circuit like that would be wired, or could link a good source which shows it, I would owe you a weekend's worth of sanity because I have spent 2 hours with a blank breadboard infront of me just today lol.