Found on a cookie box. My guess is NFC or RFID inventory tracking, but not sure.

Component is on the top left in the first picture. Bottom left on the second. It’s a slide switch. I got my iron very hot, using a small piece of braid. And tons of flux. Mixing in some regular solder in before trying to wick off. Do I need to clip the pins to get it clean? I’m just trying to get the dang thing out.

I purchased this 4 inch CRT online as a project to turn it into an oscilloscope. I hooked it up to 12V DC power as it called for and soldered in two pots for contrast and brightness, 1k and 50k ohms respectively (top left of board in blue). As far as I understand, turning on a CRT with no input should give some sort of visible raster lines or a dot in the center, but all I can manage is an extremely faint glow. I can hear the 15khz whine while it's on. What could this issue be? Is this normal and I'm tripping? The display is identical with the deflection coils both plugged into and unplugged from the board.

If there is a better subreddit to post this please let me know

EDIT: Thanks to everyone who commented. I have what I need now. You people are amazing!!!

I’m looking to replace this cap (the back has cracked apart). I need to locate a suitable replacement but am not sure about the specs. Any assistance is much appreciated. Below is my best shot at it

Type: Polyester film capacitor? Can any other type be substituted?
Value: 0.0047uF ?
Tolerance: 20% +/- ?
Voltage: ?

Hi all-

I have a flood light that I don't necessarily need. It's battery powered by 3 C batteries. The issue is this: the timer sucks. I was going to use it in a shed that doesn't have power going to it, for the rare occasions I need light in there. But, the timer only lasts 30 seconds on. That doesn't work at all for me.

I'd prefer either a longer timer or no timer at all and just operate it via the on/off switch. I'm familiar with electronics and pcb's, ic's,etc.

Admittedly, I maybe over thinking this. My first instinct was to disconnect (desolder) the ic for the timer. Then, after some time to think about it, I also thought to just bypass the pcb altogether and wire the on/off switch to the unit directly. I'd still be interested in knowing which ic to desolder and if that route is even feasible.

I'm including a pic of the pcb along with the stampings on the ic's.

TL;DR: Is it possible/recommended to remove the ic controlling a timer for a flood light to have the light stay on longer or is it better to just rewire the on/off switch and bypass the pcb altogether?

First off, the node connected to the side of Z2 doesn’t really make any sense.

But beyond that, the idea here is to turn the NPN off under OV conditions right? No collector current => Vgs = 0V. But how can the zener plus voltage divider circuit turn the NPN off?

Is the idea that it “shorts” the voltage divider once it reaches the reverse breakdown voltage?

I am attempting to repair this PA speaker and I don't know how to put this circuit back together. The cap is 2.2uF ±5%, I think it's to filter high frequencies into the tweeter. It's brand new since I suspected the old one was bad, but even in its old configuration it didn't work. The tweeter has continuity so I think it's okay. So does the L Pad. Where do I put these into this circuit? The red and black wires are for the tweeter.

Thanks in advance

I'm trying to get my Pico to run some servos kind of like Adafruit's Midi Controlled Robot Lyre. But i keep blowing up the Pico. I'm using this or a similar 12V to 3V board with a barrel jack to power the PCA9685 servo controller and the Pico since i want to run it without plugging it into both USB and Power. I'll measure the 3v3 output from the power board before and after plugging stuff in, measuring like 4 or five times, when i finally want to run it, poof, smoke, dead pi, measuring 12V on the 3v3 port. What am I doing wrong? are all of these boards faulty, I've tried AliExpress, Amazon and PiShop, same thing. Am I doing it wrong? Incredibly likely. Please help here's a circuit diagram.

Basically I'm designing a clock using vacuum tubes as a project.

I've been exploring a couple binary to decimal circuit designs, and as I was looking at the Heptode tube I wondered if it could function as a 4 input AND gate.

I understand that the heptode wasn't designed for this purpose, and that some models have some of the gates connected internally, but some models don't is there any reason why I couldn't just buy a model that doesn't have the gates internally connected and use 1 heptode tube as a 4 input and gate?

Any advice from someone who has more knowledge about vacuum tubes would be nice.

I'm looking for something like this, ideally this exact part:

It's a 2.5 mm TRS connector, but it has springs to contact the PCB.

But springs are not even a mounting type on Digikey for example:

I recently opened up a CRT I recently got since it doesn’t power on and found a hefty amount of corrosion around a lot of the diodes, is vinegar safe to use? I’ve been using 99% isopropyl but heard that doesn’t neutralize it, Ive taken all necessary precautions like discharging the tube.

I cant tell if the connector is push fit or has a flip to ooen clip or something?

Really dont want to break it and I cant seem to push it in.

I'm working on a project that requires the running of multiple 16 wire (analog and digital) buses from a master board to multiple breadboards for prototyping.

I can use a 2x8 or 1x16 pin header on the master board. I would like to use 1x16 on 0.1" centers on the breadboard ends so they plug into the breadboard rows.

The only solution I can come up with is to use 2x8 pin ribbon cables with a PCB adapter board that goes from 2x8 to 1x16.

Is there a better way ?

Thanks

I need help to figure out the correct wiring for my speaker tone switch. Any help appreciated.

Good day all,

I saw a picture online that for whatever reason reminded me of Cyberpunk. It's here, the right side especially kind of looks like something you would see in game during a glitch or in the world or in that dimension (I've forgotten the name) that is like cyber world where I think Jackie ended up.

Then, I was like can't we have artistic boards that the traces themselves make up the image or art but I wasn't sure how it will work logically so I tried this first board, using the pill design from the skull in the menu.

Parts used:

• C1, C7: 4.7μF cap (TMK212AB7475KG-T)
• C2, CFILT1: 0.1μF (885012206071)
• C3, C4, C_FILT2: 1μF (TMK107B7105MA-T)
• C_X1, C_X2: 10pF (06033C100KAT2A)
• C_X3, C_X4: 6.5pF (CBR06C659B5GAC)
• Red LED: LTST-C190KRKT
• F1: MF-FSMF050X-2
• Mounting holes are M2
• USB-C Receptacle: Korean Hroparts Elec TYPE-C-31-M-12
• Header sockets for the screen are 2.54mm
• The screen being used: here
• R1, R2: 10kΩ resistor (SG73P1JTTD1002F)
• R3: 47Ω resistor (SG73P1JTTD47R0F)
• R_UCC1, R_UCC2: 5.1kΩ resistor (RCS06035K10FKEA)
• Buttons (S1, S2, S3): D6R90_F1_LFS
• MCU: STM32F411CEU6 (datasheet)
• U2 (TVS diodes for the USB): USBLC6-2SC6Y
• U3 (LDO): NCP164CSN330T1G
• Y1 (seen in datasheet as f_LSE, 32.768kHz): 830009709
• Y2 (as seen in datasheet as f_HSE, 25MHz): ABM3-25.000MHZ-D2Y-T

For the capacitors used for the crystals, I used the load capacitance given, subtract 5pF as stray capacitance then divide by 2.

The schematic (I understand some don't like global labels but it helps with keeping things more neat I feel so I apologize):

The LED is to see when it's on and plugged in. It's also using 3.3V from the LDO so that will tell me the LDO works. I want to use the bootloader that comes with the MCU and use the USB to both power and program it without like ST-Link so is my boot button setup correct?

I also have the reset button and a regular button for toggling. I'm imagining plugging this into my laptop, programming the screen to show laptop stats like CPU etc then when I press the button, it can show something else like a slideshow of cyberpunk art. I hope that makes sense.

I also hope the cap filtering at the top will work? I saw like three different configs in the datasheet with one have 6 100nF caps that I'm not sure about. Seems you can connect all the VDD and VBAT together so I did that and used 0.1μF, 1μF, 4.7μF there. All caps are X7R ceramic caps except the 6.5pF, didn't see X7R there.

I also used a bunch of estimation for this screen size and spacing since I don't have it.

Here's the PCB:

It is a 4 layer board going: SIG --> GND --> GND --> SIG. I changed the silkscreen to be red and the mask to be black. I know about black boards, hopefully PCBWay can do a red silkscreen too. Also, does anyone know if it's possible for the traces to be red as well? Thank you

All the extra traces on the top and bottom, I just assigned those vias to GND.

This is a personal project to me, just was interesting to try out, I also have some other designs in mind so I want to try multiple boards. This is just the first one. If when I get it, it works and can be polished, I'll open source and post like code and documentation.

Thank you all.

Hi all, I'm designing a test board for a 160 W BLDC fan motor. It uses an ESP32-S3 with three temperature sensors, a differential pressure sensor, a display, an SD card, and an RS485 Modbus connection to a Selec energy meter. Speed is set by three triac channels (low, medium, high) switching the mains through optocouplers. Power comes from USB 5 V through an AMS1117-3.3.

The schematic is attached. I'd like feedback specifically on:

RS485

• Transceiver wiring (MAX3485), DE/RE# control, and termination
• Bias resistors for an idle bus and whether they're needed on a short run
• TVS placement and ground reference

Mains section

• Fuse and varistor order, and the NTC for inrush from the BLDC controller
• Triac and optocoupler choice (MOC3063/BT136 vs. 800 V parts), and the gate resistors
• Snubber placement across the triac (I've left them unfitted for now)

EMI, clearance and leakage

• Clearance between mains and low-voltage nets, and whether my slot and spacing plan is enough
• Creepage and leakage on the optocoupler and triac side
• Common-mode and radiated EMI risks from triac switching, and any filtering I should add

General

• Are the connections right? Anything you'd change before a PCB spin?

I'm not an EE, so plain feedback is very welcome. I'll post the PCB layout once it's routed. If anyone wants high-resolution photos of the board or the schematic, here’s my Drive link: https://drive.google.com/drive/folders/1faougHNje7w3B6eu84qCuEpPya0Ccdzw?usp=sharing

Can anyone help me identify this diode? Doing a fun little project adding the missing SMD's on the Wii Family Edition to re-add the gamecube ports, Mainly to teach myself micro soldering. Only missing this diode from my digikey cart. This diode is missing from 2 of the 4 ports.

The diode is on the data line if that helps. Package looks to be sod-523 maybe. Cant really tell if it would be a TVS or zener (but I dont really know what im talking about). Any help is appreciated. Thanks all.

I want to experiment with xenon flashlamps. I'll use a boost converter to charge up photoflash capacitors and then dump the stored energy in the lamp.

I have my eye on those ring-shaped lamps commonly sold on eBay and called "300W". Which seems to refer to the MS series from Godox, e.g. MS300. The instruction manual from the manufacturer claims a watt-second rating of 300.

So as long as my capacitors store less than 300 joules, it won't explode? Well, it's not so simple because I don't know what ratio of capacitance to voltage to use. I could use a high voltage, low capacitance bank, or vice versa while keeping the stored energy the same.

Now that I'm thinking about it. It is a bad idea to use a "mystery" lamp. But what does the voltage to capacitance ratio even affect?

Hello everyone,
I’m trying to identify and replace the ultrasonic piezoelectric disc inside the misting module of an OASE biOrb AIR 60 terrarium.
The original disc:
Is marked KR 213PF
Measures approximately 20 mm in diameter
Has no soldered wires and uses pressure contacts
Is held in place by a silicone gasket and a metal retaining ring
The original misting module was failing but still produced a small amount of mist.
I tried replacing the disc with a generic 20 mm, 1.7 MHz, 1.2 mm ultrasonic atomizer disc. The water now bubbles vigorously, but no visible mist is produced.
I have checked the disc positioning and gasket, without improvement.
My questions are:
Does anyone recognize the marking KR 213PF?
How can I determine its original resonant frequency and capacitance?
Could the bubbling without mist be caused by an incompatible disc, or could the driver circuit also be faulty?
Does anyone know of a compatible replacement?
I don’t have a multimeter. I have also contacted OASE to request the original disc specifications.
I can attach photos of the original disc and the misting assembly.
Any technical advice would be greatly appreciated. Thank you!

I ask for forgiveness if my English skills and electronics experience is not sufficient enough for this sub.

I have been working on this mini CRT (radio? cd player ? ) for a couple days after salvaging it from my local church before it got obliterated.

Ik working on CRT is dangerous but I checked that the CRT itself was in good condition before touching only the driver board.

After examining the mess (it was even more chaotic) I realized it worked perfectly by bypassing the potentiometer regulating the “contrast” I think (middle potentiometer snapped). As you can see I’m just trying around until I get it in working condition before soldering any permanent changes in the main board.

The issue is the while trying to display anything more than static I was using a cheap Arduino knockoff with the tvOut library to display a test image.

The issue is: while displaying through the RCA yellow port directly with jumpers cables I noticed a bad clarity in the signal and having no potentiometer replacement I can’t easily change the contrast, I only have access to the v-hold (I’m sure) and brightness(?) ?

If I instead try to use a real RCA cable I have to swap the temporary resistor regulating the contrast to a lower value to see anything BUT this also swaps the black and whites colours for some reason ?

Currently I have started out with a 1M Ohms resistor, then 100k. The old snapped potentiometer had a 1M marking but I didn’t understand if it was a model type or a real resistance range?

I’m pretty sure this is a standard driver board in the china knock off / cheap mini CRT systems but I couldn’t manage to find any info.

Once again I’m truly sorry for my terrible lack of understanding of electronics and of the English language.

I can’t find any drawing on this for the burned up thermistor. What would be the best substitute to put on there? When I pulled it out it was maybe a 5D-11? It was so charred it’s was illegible.

This is a button for a smoke machine. The smoke machine it’s originally for blew up. With the help of a breadboard and and some jankiness I figured out that pins 1 & 2 need to be swapped for this to work on the working smoke smoke machine. My multimeter is broken so I can’t use that.

Pin 1 seems to just be power Pin 2 does the LEDS (Just red when not pressed, green and red when button is pressed) Pin 3 activates smoke when button is pressed.

This all connects to an xlr style 3 pin connector.

I want to swap pins 1 & 2 in the button housing, is someone smarter than me able to identify pins 1 & 2 based on what I’ve said and this picture? Or is this a hopeless task and I should just buy another multimeter(which i must do anyway).

Also in case you’re wondering how the other smoke machine broke: I made an xlr y-splitter so the button could work on both machines at once (I can see how thats not possible now) and when I pinswapped 1 & 2 on just the currently working machine while everything was plugged in, the other went pop and my breaker tripped. When looking looking inside I found that I shorted the two machines live signals in the fog pump which is the component that blew up and let out the wrong kind of smoke.

I have my first keyboard the Yamaha PSR-E203/YPT-200 that I use regularly. It currently has started to leak noise into all audio output and need to perform capacitor replacements. It contains 3 main boards with a central one where the audio processing and DSP takes place. By my own research I found a Japanese SM but I do not read or speak it.

For the time being I could pass by with the Japanese service manual and google translate. But, if anyone could help me find it in English it would be so much better.

Link to Japanese service manual that I have on my google drive now.

I have the owners/user manual but it doesn't help with any repairs.

Hello, I have a project where i mod my thinkpad by designing a PCB carrier board, making a whole "semi-custom" motherboard using a compute module as the brain, and I would get a custom IPS display that would fit the laptop's display border, but I can't even find one that would be the same ratio and size. If any one of you had this problem, how or/and where did you solve it?

Trying make sense of a little kit with even smaller amount of knowledge. looking at the pcb, chip and chip holder I think this is how they should be mounted with the dimple at the top / 12 o'clock. I thought the dot on the pcb was used to orientate the chip but there's no dot on the chip.

tl/dr: is the chip and holder the right orientation as in the picture?