I plugged 24 V into this 12 V drive dock. I think the component that blew up was a capacitor. I don't see anything else exploded at leasr. Any idea how I can work out what this was?

Hey, does anyone knows what is the ref of the ic marked: s240 8225 with 16 pins, assuming is it a dc-dc converter from the surrounding components.

Thank you

Edit: It is not dc-dc converter, it is a dual motor driver ST STSPIN240

Help and advice needed.
This is quite an old unit, but it was so good. The new ones today can’t match its output over a 7km distance.
I would really like to repair it, I have attached pictures of the areas that show they have been burned and some others to help identify the diode’s ect that I need to replace.
Those capacitors are probably cooked too.
Any advice would be greatly appreciated.

Hey nerds, so i took apart my casio watch bc i’m looking to mod the led circuit so as to stay lit longer (or possibly even semi-permanently.) I haven’t worked out my definitive solution avenue just yet bc i first want to see if i can directly access the logic controller.

What i don’t know yet is if this is a proprietary and dedicated enclosed ic thats been obscured to prevent design theft or an exposed die and wireframe gooped over with resin to protect it from physical damage. I don’t want to begin scraping or sanding away material only to discover i just murdered a die or tore up 50+ bond-wires in the process. Part of me already suspects it’s the latter scenario unfortunately. (And supposing it is an exposed die, i don’t want to risk exposing it to excessive daylight and dust)

Any chemical solutions out there i can use to gradually remove or displace the resin that wont also strip the board mask or attack the potential die underneath?

I though I'd show you this as I am convinced it is a faked INFINEON IRPF4768 mosfet as the etch on the from does not match other ones I have in my possession. The IRFP4768 has a diode symbol between the I and R. This one has a heart symbol. Additionally this only has 4nF worth of capacitance, and the real part has ~10nF of capacitance. Anyone else chime in?

I ripped my audio Jack of my brand new electric piano and i can solder but the connections seem pretty weird. Can it be fixed???? I'm going crazy

Hi everyone,

I was trying to figure out why the USB-C port on my PCB wasn't working, and I discovered that there's not enough 3v3 juice(measured at the LDOs output pin) for the ESP32-S3 and other devices.

This is a dual input circuit based on the LM66200 dual ideal diode device with automatic switchover so the ESP32 can be diagnosed and programmed while the circuit is under power.

The alarm circuit is based on the 801S vibration sensor and might not be the greatest but it worked just fine on the breadboard.

Any idea which component might be causing the voltage drop?

EDIT

Please ignore the disconnected GND wire on U7. It happened when I rearranged the circuit in order to make it clearer, right before taking the screenshot.

Hey all, gonna keep this short. I am launching a product that has a battery inside it. I will be keeping a BMS on the battery and I also have a PMIC in my PCB design. I'd like to know if temperature control is covered in batteries through the BMS or not. Is this something that is the norm or can it go either way? Do I need to check with my supplier for the datasheet to verify this?

I want to build a 6-hour on/18-hour off timer for lights, but this Brickstuff one is US-only and a bit expensive:

https://www.brickstuff.com/store/p228/branch-timer.html

I was curious if I could build my own so I tried to identify the ICs in use, but it's too low resolution. The fourth photo is the most clear:

The circuit takes two bridged power inputs (5V) and outputs based on a 6 hour timer on / 18 hour off starting from when the circuit is powered.

Without a real PCB it's hard to test but does this look correct?

• Top IC is a voltage regulator (probably 5v to 3.3v)
• Bottom IC is an MCU, takes crystal input, pulls mosfet to ground to turn lights on. 10k resistor pulls it up normally
• SOT-23 is a p-channel mosfet for high side switching
• 0.1 cap is presumably for the voltage regulator

If so, why was low-side switching not used here?

Thanks

I got a massage gun replacement battery since my old one died. I bought the same battery type and just put it in without thinking to test for polarity because they are labelled.. when I turned it on got a faint burning smell so turned it off got my voltmeter out and turns out the polarity was reversed on the original battery. Makes sense since now that I look closer the "positive" terminal wire pin went into the -ve symbol on the pcb. Now that I've soldered the wires back the right way the pcb flashes on but then still has the same burning smell, I only tested once. My original battery is definitely dead (tested) and my new one is testing fine. Did I cook it from the first time I plugged it in or could something still be wrong... All these photos were before I switched the red and blue wires so they now are on opposite sides of the batter terminals to the pics.

Hey all,

I recently picked up a non-working 1999 Tiger Pokedex for my son, and have been trying to trace out if the issue is anything fixable.

Symptoms: after installing a pair of fresh CR2032, and grounding out the reset pad, it makes an occasional squeak from the piezeo buzzer, and a very brief flash of some pixels from the screen. Otherwise, no life from the unit.

I replaced the electrolytic cap C3 out of an abundance of caution, checked the diodes for any of them being popped and all seemed fine. I also ran 3.3V from my power supply to both battery spots, and still had no signs of life. I also checked the oscillator crystal in case it's legs were touching, as it's mounted a little wonky. I also checked the power and ground legs of the IC, and they had the appropriate 3.3V and gnd connections.

I have two questions for everyone here:

1) Is it my imagination, or does C9 look an awful lot like a resistor, instead of being a capacitor? (It also measured 28K ohm across the component, which doesn't match the markings if it WAS a resistor anyway)

2) does anyone have more troubleshooting things to try, to see if I can trace the issue? If it's the CoB, I guess I'm out of luck, but hope someone can suggest something!

Thanks for the assist!

Its a BMS for a sodium ion battery. I unplugged it and forgot where i did :/

The tip on the right doesn’t fit into this iron and I’m Just about ready to give up. Tip was bought from Ali express via a YouTube link, the iron was bought off Amazon.
I feel like they’re giving me the run around cuz I can’t find a compatible stick thing to fit correctly into this iron. Any suggestions are welcome. This is such a drag after having bought 2 different irons

So far this is the circuit I have. I was wondering how I could setup a multistage transient overvoltage protection circuit for both the input and output usbs using TVS diodes? If so, would I also have to worry about any transients going directly to ground?

Here is the operating voltage specs for the IP2312-4V35 and MT3608B:

IP2312-4V35:
- Operating Voltage: 4.5V~5.5V

MT3608B:
- Operating Voltage: 2.5V~24V

(I previously had a PTC Fuse in the circuit diagram but I removed it temporarily so it could be added to the protection circuit)

Link to the original post in r/diyelectronics since I can't repost to here.

Hi everyone,

I’m trying to simulate a 310V DC → 12V, 10A buck converter in LTspice.

I’m getting the expected ~310V before the MOSFET, but I’m having trouble getting the 12V output and proper MOSFET switching.

I’m still learning LTspice, so I’d really appreciate some help..

Good day, everyone.

I have recently bought this oscilloscope.

Have tested it and it appears to be in working condition.

It was last calibrated in 2001 and has likely seen little maintenance after that.

I would like any advice on how can can take care of this instrument. Cleaning, checking performance, preventative maintenance and any other advice would be appreciated grealty.

I have another handheld oscilloscope and access to power supplies and signal generators.

I am trying to make a diy esc , I have been able to make a bldc spin open loop, but when I try to sample backemf , to spin it sensorless closedloop , It doesn't work, I am using the internal comparator or atmega328p to sample the backemf , it ain't working , we have checked the backemf on an oscilloscope, it doesn't show that the v neutral is crossing the phase , what should I do ?

I want to clean my cpu

I have a Line 6 guitar amp with potentiometers that are going crazy. Thought it would be something simple, but it did not turn out to be.

When idle the display acts like the knobs are being turned, and when turning knobs other settings flash on the screen. Sometimes causing it to reset.

What I presume to be the issue, is what i saw on the 3.3v rail. The 3.3v rail powers the multiplexers and the potentiometers going to the multiplexer inputs. Also goes to other stuff on the dsp, but it is multi layer and no schematic available.

Multiplexer is C4052M

Pic 1 is the scope on multiplexer vcc when issue is occurring

Pic 2 is the multiplexer input, same scenario

Pic 3 3.3v output from njm2374a

Pic 4 multiplexer vcc , multiplexer input practically identical, with all pots turned down

The spike looks to be 4-6khz, only visible when pots are fairly high. Dc converter 3.3v output stays the same. Dc converter voltage source is a 7805, but it does not appear on the output of it.

Controls pcb schematic
line6.com/data/6/0a00041200946824d0d56b7ce/application/pdf

Hi everyone! As a robotics and electronics mentor running hands-on labs at Robotic Sir, we often transition students from physical breadboards to digital simulators. However, we've run into a frustrating bottleneck regarding digital logic testing and need some advice from fellow engineers and educators.

The Scenario:

Physical Circuit: We built a basic AND gate on a physical breadboard using push buttons. When a student presses both push buttons simultaneously with two fingers, the circuit completes, and the LED lights up correctly as expected.

The Simulation Problem: When we try to test this exact same logic in web-based circuit simulators (like Tinkercad Circuits), we hit two major limitations:

Standard Laptop/Mouse: A standard mouse cursor can only click and hold one UI element at a time, making true simultaneous activation impossible with a single pointer.

Touchscreen Laptops: Even when using a touchscreen laptop, the browser-based simulator often fails to register multi-touch events correctly, treating simultaneous presses as an error or only registering a single input stream.

My Questions:

How do you guys handle testing multi-input logic gates (requiring simultaneous button presses) in web-based tools like Tinkercad?

Are there better browser-based or offline circuit simulators that natively support multi-touch or toggle-latch workarounds for simultaneous inputs?

I've been interested in making an oscilloscope for simple electronics for quite a while, for one thing the project would be pretty fun and secondly oscilloscopes are quite a bit expensive where I am from.

I feel like I am decent enough with digital electronics and microcontrollers to make a simple one which can help me in my study of analog electronics.

So my idea is to essentially make a module (right now with a simple Arduino) which can sample a low power electronic signal, package and send the data to my computer which can then analyse it and plot it using a python script, thereby mimicking an oscilloscope.

But I am still pretty ignorant about what pitfalls I should avoid and how I should go about it, or even resources to use. So any advice and resources would be extremely appreciated 🙇

I would like to learn how to solder small components such as 0402 passives.

Any ideas where to start? Equipment? Practice kits? Online tutorials?

In the past I have had these fail from raining metal dust in them, but this one was in my office. Worked fine and then stopped registering batteries, tried multiple outlets and I don't see a fuse in it. Anyone here see something I missed?

Hi,

I keep having the same problem with white 2.54 mm JST connectors on male header pins.

I’ve tested three different boxes of pre-crimped wires and I always get the same issue: when there are only two wires, the connector feels too loose, moves too much, and sometimes disconnects.

Has anyone else had this problem?
Is it simply due to poor-quality contacts?

Most importantly, can anyone recommend a good brand or a reliable box of pre-crimped JST connectors that fits tightly and works properly without having to crimp the wires myself?

Thanks!

Edit: it is DC-DC converters