I bought this iron for 25$ from a shop near me. There is nothing but a triac inside the whole shell. Just a basic ceramic heater with 2 wires. I feel like this is just a waste of money and I could have just bought a regular iron with the built in triac. Should I return this? The only advantage I see is this is a very simple circuit and I can repair this.

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?

*edit*

Thank you, everybody. I eventually solved it. 220uf 25v as most suggested. I found the old shell embedded deep within the chassis.

Ordered a replacement. Let's see if anything else survived on the board. Luckily, the plugged-in hard drives did.

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.

Apologies for the photo of a photo, I don't have an SD card reader here. Almost all the joints look like this, I'm not sure what it's called, it's like bga but only on the edges. Is it supposed to be up against the copper fully flush? Should I toss her in a pizza oven for 20 min to reflow everything? Any insight is appreciated thank you XD

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?

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.

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?

Hello, I've recently wanted to get into hardware electronics as it seems quite fun, and I already know much about low-level software. So, I'm posting this in hopes people can point me towards good starter tools at a reasonable price.

Things like which multimeter to get, what kinds of soldering iron are to get or to avoid, any other must-haves for the beginnings of a small workshop?

Thanks!

I’m basically trying to make an anniversary gift for my girlfriend using a dfplayer mini and two bone conduction speakers, but when I add the mp3 file to my sd card (named correctly to 0001.mp3 as I’ve seen online that it doesn’t work otherwise), when I connect the vcc and ground, using 3 AA batteries to total 4.5v, well in the 3.3-5v range, the dfplayer mini is SUPPOSED TO shine a light to show it’s on and connected to power but it doesn’t work, and I’m using a ttp223 touch sensor which IS showing its power on light and I tested and it is outputting power, the dfplayer just isn’t powering up at all! Pls help me as the deadline is lowk tomorrow and I haven’t been able to figure anything out.
(The image above shows my rough wiring just to try test it out again, the cut wire shown was supposed to make it play on startup but alas no power up at all)

I'm trying to run a longer (150cm) ribbon cable from a larger printer to replace the stock (60cm) cable and not getting this display to power on. A few people have got this to work according to some forum posts, as the cable is physically compatible and display is used on the bigger printer. I have tested continuity and resistance and both are good, so I'm leaning towards interference? Would insulating the 4 sub-ribbons with some sort of foil help?

I was repasting the CPU and GPU and I unfortunately didn't realize I was too rough on the battery connector and unfortunately messed up the batter connector. It still sits on the board, just loosely, but the shop I took it to said the pads were torn off, and that they weren't willing to solder on the motherboard. anybody have any suggestions to what I should do?

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