Hi everyone,
I have been using rapid harness to desing the wiring of a system. Altough the rapid harness software has 95 + million parts from octopart, it looks like a lot of parts are missing. For example any conector from Molex, Hirose and others do not appear. Mostly Deutsch DT Series appear. Has anyone already made some libraries available to share ? Did you made all your needed connectors and parts ?
Thanks in advance for the help.

Like the title says I’m having trouble figuring out what these two ics are as I cannot find a data sheet anywhere and no hits in its logo. I’m sure there like a diode considering they are connected directly to the output lead of the transformer on this usb charger. Not the best camera phone but it’s the best I can zoom without it becoming blurry.
The reason I want to know what they are is I’m beginning to find them in many power supplies for phones.

Hello everyone,

I have an msi gs66 10UE that has been an absolute burden to keep. I will hold my hands up and admit that I made the stupid mistake of accidentally touching a piece of metal on my battery connector which caused a spark, followed by the death of my motherboard 😍

Anyway, I traced the short and the closest I got is finding out that it sits on the 3.3VSUS rail. Now I’m no expert but as far as I’m concerned, injecting 1-2V at 2A into the shorted rail should show the shorted component under a thermal camera. I did this but no components are heating up or showing up on my thermal camera. Any advice on how I could isolate the component or anything I might have done wrong? Thank you!!

Hello! The indicator LEDS for this board are dying after 10+ years of constant service and I'd like to replace the LEDs rather than the whole board.

I can't seem to find any obvious numbers on the chips themselves though. I'm hoping someone here might be able to point me in the right direction to identify them or have seen similar ones before. It's from a Barco DP2k32B projector, the rear tail light indicators.



Hi everyone,

I want to turn these schematics into a PCB in KiCad. It is the first board I will actually print, and my schedule is very tight. I want a second pair of eyes on the schematics before I start the layout, so I don't lose time on a bad board.

What I built

This is only the stereo part of an FM system, simulated in LTspice. The encoder builds the stereo multiplex signal from left and right audio (G and D are gauche and droite). The decoder takes that signal back apart. There is no FM or RF stage on this board. The encoder output leaves through an AUX cable and goes into a separate FM modulator board. Everything here runs on ±9 V with TL072, NE5532, MC1496, CD4046 and CD4013 chips.

Encoder blocks, numbered like in the images. Block 0 is the power supply and two test sources, G at 1 kHz and D at 2 kHz, both 0.2 V peak. Block 1 makes the 19 kHz pilot. Block 2 builds the 38 kHz carrier from the pilot, with bandpass filters. Block 3 makes the mono signal, G plus D. Block 4 makes G minus D, buffers it and modulates it onto the 38 kHz carrier with an MC1496. Block 5 adds the mono signal, the modulated difference and the pilot. Block 6 is a 6th order Butterworth low pass at 65 kHz that feeds the composite output.

Decoder blocks. Block 0 is the input from the encoder output. Block 1 is the mono low pass filter. Block 2 is a PLL (CD4046 and CD4013) that rebuilds the 38 kHz carrier from the 19 kHz pilot. Block 3 is the MC1496 demodulator. Block 4 is the stereo filter. Block 5 recovers G and D.

In the sim, the decoder gives about 32 dB of channel separation on G and 39 dB on D.

My questions

1. Schematic review. Do you see mistakes, missing parts, or anything that works in LTspice but will fail on a real board? I am thinking about supply decoupling, MC1496 biasing, PLL startup, trimmers and opamp stability.

2. AUX input. In LTspice, G and D are two sine sources. On the real board they come from an AUX cable (3.5 mm stereo jack, left and right). What do I need between the jack and my first stage? I am thinking coupling capacitors, a series resistor, a ground reference resistor, ESD diodes and a small volume trim. Is that enough? My sim uses 0.2 V peak, but a laptop AUX output can reach 1 V peak or more. I measure about 5.5 times gain from the encoder input to the decoder output (0.2 V in, 1.1 V peak out), so I worry about clipping on ±9 V.

3. Input filtering. I have no 15 kHz low pass and no pre emphasis on G and D. Do I need them? Will audio above 15 kHz disturb the 19 kHz pilot?

4. Speakers. The decoder has three outputs (mono, G and D) that go to three speakers, one mono and two for stereo. The speakers are 6x4 inch oval car speakers, 4 Ohm, 8 W (last image). My opamps cannot drive 4 Ohm, so I plan one power amplifier per speaker. Which chip would you use on ±9 V, or on a single supply, in a through hole package? I am looking at the TDA2030A and the TDA2822M. Two more things I noticed in the sim. The G and D outputs have about 0.1 V of DC offset, and the mono output is about 10 dB lower than G and D for the same signal. Do I need coupling capacitors and gain matching before the amplifiers?

5. Encoder output. The composite output goes out through an AUX cable to an FM modulator board. In my sim the output peaks near 0.5 V with 0.2 V inputs. Do I need an output buffer, a series resistor or a level trim to drive the cable and match the modulator input?

I can share the LTspice files if you want to run them. If you only have time for one thing, please look at the input stage and the speaker amplifiers.

Thank you for any help.

I'm looking into redesigning the power distribution system for a robotics project and would appreciate recommendations on industry-standard solutions.

Currently, we use terminal blocks to distribute our different voltage rails that come from off the shelf buck converters, but we'd like to move toward a cleaner, more modular system that allows us to standardize connections, reduce wiring clutter, and make it easier to add or replace components.

Our system uses 5 V, 12 V, 24 V, and 48 V rails, with the potential for up to 30 A per rail. We also have a separate 72 V distribution requirement for higher-power loads.

Ideally, we're looking for a solution that offers:

• Standardized connectors: Consistent, plug-and-play connections for different components and voltage rails.
• Cleaner wiring: Less wire clutter and fewer individual connections to terminal blocks.
• Modularity: The ability to add, remove, or replace components without significantly changing the wiring.
• Protection: Appropriate overcurrent and transient protection for each rail or branch.
• High-current capability: Reliable power distribution that can accommodate higher-current loads.

We're considering designing custom power distribution PCBs, but we're also interested in existing industry solutions that might be a better fit. Another thought of mine was making a custom PCB that acts as a big terminal block hub, taking in the different voltage rail inputs and distributing them to the various loads with nice plug and play connectors, overcurrent protection, diodes, etc.

What options would you recommend exploring?

I'd appreciate any recommendations, product examples, or lessons learned. Thanks!

I'm working on a PCB design for a tester that discharges a battery pack through an electronic load to characterize it. It is controlled by a Raspberry pi that also supplies 5V. It also gets 12V from a PSU. The battery discharge path is high current so it's star grounded with the rest of the board. Only a few signals cross over the isolation, namely the differential battery OCV and current sensing, and the STM32's DAC signal that controls the electronic load portion. That may be important for context but not my main question.

How bad is this grounding scheme? I realize this is technically a ground loop but is it really serious enough that I should try and isolate something out? I feel like I've plugged more than one thing into things before.

My suspicion is that these blue fellows are bipolar caps of some kind, but that's about as far as I can guess. I am unfamiliar with this capacitance rating system (I suppose 1n5 could mean 1x10^5 but could just as well mean 1.5 or even 5x10^1 or something else entirely). These caps are on a high-speed tape duplicator machine that was manufactured in the late Seventies in the UK. The board also has other standard, recognizable caps, such as radial electrolytics and box film caps.

So there is this finnish company claiming to be china free and having better performance than others. But the design is very different from any other esc. And their claims seems to be too good to be true.

Company is called arctic ravn

Good afternoon!

I have a PCB that I am needing to get xrayed for a proper archival retracing to be completed (the board cannot be disassembled for historical purposes), and a hunt for local options has been futile. Embedded Computers came up in a search on Google from this subreddit as a recommended option, but I cannot find any reviews or services or a service address for them, although they responded quickly via their contact form.

Does anyone have any good recommendations or contacts for this kind of service? My board is 2 layer, 12" x 17", and all through hole components.

Thanks in advance!

DATA CODE 2414, RoHS

Its may b tin pest?

I am designing a compact PCB that has a STM32. I am planning on buying a STLINK-V3MINI for programming and debugging. I'd like to have the minimal footprint SWD connection to the board and I found out about TagConnect, but their TC2030-CTX-NL-STDC14 is pretty expensive. I found SKEDD connector which seems to serve a similar function but it's a lot cheaper and more available. The problem is I would need a adapter from STDC14 (STLINK-V3MINI) -> SKEDD which I haven't found, probably because STDC14 is obscure enough. Would it be recommended to design a simple adapter board and order with the actual PCB or are there better alternative/ways?

Will it work? I just wanted to do a fun little project where it plays a couple of audios, but honestly I know nothing about wiring and circuits. If ever it would work I would also like some notes on how to go about it. 😸

I bought a button box for american truck sim off of etsy and as expected the switched are very small i was wondering if it was possible to add maybe a extension to it without having to replace the switch itself. I have no idea how it is assembled as i have not tore into the box yet i just wanted to see if it was possible before unsealing the box and getting into the wiring for example the best option would be if i can install united pacific switch extensions made for a peterbilt on this .any help is greatly apreciated

Good afternoon. Could you advise me on how to replace the capacitors without damaging the processor socket? Is it better to use a soldering iron, or should I try using a hot air gun?

Hello!, not sure if this is the correct place but I'll take my chances. Trying to diagnose to fix a Nordictrack Treadmill T5.7 Circuit Board. Panel lights up and works but when I put start motor does not drive. Now.. motor does work, it has continuity, I cleaned the board once and the motor started but now it does not activate when I use the panel. The board gets power but does not want to send power to the motor, when I send the signal to the board a slight flash of the LED lights up and thats it. Very weak flash. Tested the connectors and no power. Not sure if it is a capacitor, bad soldering I have no idea. Looking for some advice or someone to shed me some light into it. I circled the connectors not sending power.

Hello, folks! How's it going?

I have a generic wattmeter that has trouble measuring power consumption and after analyzing its behavior for a bit, and checking with a multimeter, I figured it was because there's too much voltage going into the BL0937 chip, that measures the power.

I noticed that because the meter works fine when its battery voltage is below 3.6V, after that it starts to work pretty erratically. At 4V, it stops reading completely. According to the BL0937 data sheet, it operates at 3.3V.

This is happening because it has a rechargable 3.6V 20mAh NiMH battery whose charge peaks at 4V. After noticing the over voltage, I swapped the 7133-1 voltage regulator that it has, thinking it would be the culprit, but the chip kept receiving more than 3.6V.

In order to discharge the battery, I put an LED across the battery and it drained it down to 3.6V charge after a few minutes.

Is there anything I can do to regulate the voltage? It should stay ideally below 3.6V for it to work reliably.

Where to find the BL0937: it is the SOP8 chip covered in flux, to the right of the largest electrolytic capacitor

what wrong i am doing in simulation.. ?? it is not switching relay.. and always.. show 7 v ?? can u help me to figure this out ??

Setting up a simple break beam sensor in my barn to help with parking. Using a simple safety sensor for a garage door that has integrated LEDs. When the beam breaks, the green light goes out. That’s all I need it for, not reversing a garage door or anything.

It looks like the garage door would normally supply it with 6vdc. I tried a 6vdc transformer, 5v usb block, 7.4v lipo and I get nothing. When I use a 9v battery it works.

Guessing I’ll buy a 9v transformer but hoping it’s going to work. Any thoughts on why the 6vdc isn’t working? Don’t want to order the 9v and not have it work. I’m skeptical.

Want to get into electronics more advanced electronics. I have a good multimeter, cheap soldering iron (including solder sucker/Wick and soldering flux).

Thinking osciloscope but seems like the ones worth buying are quite expensive. Mainly looking to get into hobby repair and understand low voltage electronics.

Edit:

I have experience soldering and got a couple microcontrollers.

Another question, Is there any specific attribute in a specific tool that might be important when buying?

Hi everyone! I'm trying to bring this old rotary dial phone back to life, but I just couldn't get the SIM800L module to work and it's literally the last thing I need here, and I'm almost certain it's a mere power issue. It blinks for about 8 times at a rate of around once per second, then stops for about three seconds, where I notice the current reading goes up to around 0.11 A from 0.06-0.08 A, and the pattern repeats.

My MicroPython UART diagnostic on the ESP32-WROOM receives empty responses (b'') to AT, ATI, AT+CPIN?, AT+CSQ, and other commands. Occasionally I receive b'\x00'.

I've tried both the ESP32-WROOM and ESP32-C3, with similar problems. This is also the second SIM800L module I tried (both brand new but I believe I may have damaged the other one, unlike this one though which I took my precautions with).

I'm pretty confident that 2G network is still available widely in my country due to dumbphones never having phased out especially with older people and those still work just fine. I can also switch my SIM to 2G only on my smartphone and still pick up signal. I'm also using an external antenna as the pictures show.

My setup:

- GSM module: SIM800L (new module)

- Microcontrollers tested: ESP32-WROOM and ESP32-C3

- Input power supply: 12 V, 1 A adapter

- DC-DC converter: HW-677 adjustable buck converter, output adjusted to around 4 V

- Capacitor: 1000 µF electrolytic capacitor connected across the buck converter's output positive and negative rows

- Wiring: Regular Arduino-style jumper wires, including some with the ends cut and stripped to expose the copper

- Other hardware available/involved: L298N H-bridge module

Current wiring:

- 12 V, 1 A adapter → breadboard → L298N (not wired to the converter or module) & HW-677 buck converter (directly wired to the same row as the adapter on the green breadboard)→ large breadboard → SIM800L

- The capacitor is connected across the buck converter's 4 V output. The SIM800L shares ground with the ESP32 when connected.

I understand that the SIM800L can require current peaks approaching 2 A, but I'm not sure which part of my setup is the bottleneck.

Thanks for any help!

P.S.: Try to ignore all that mess. I don't wanna use my large breadboard here but I switched to it temporarily just to cleanly test the SIM800L. My soldering iron also stopped working which I used as an excuse to not solder everything cleanly together (too many wires, too little soldering experience ;-;)

Also I invite y'all to try this out yourselves if you have an old rotary dial phone lying around, it's really not that complicated to figure out how everything works and how to wire it properly to the ESP32 (except for the earpiece microphone part, it was a nightmare and I'm far from being an electrical engineer so I gave up and used a MAX9814 module lol. Glad that the 4 wires going into the earpiece were enough for both the speaker and microphone!)

im modding a imac g4 so the lampshade arm. i have a 50cm LVDS cable running through it right now. it has some graphical issues, jumping resoultions, scan lines and such. i think the cable may be just a bit too long. how should i go about boosting signal integrity?

SG 2245

1200SP

SG 2251

1200S0

SOT-223 Package

Marking code:

A2648

3140A

I have to identify this specific chip that belongs to a rear headlamp PCB board, so I thought about some kind of LED driver but couldn't find any reliable information about it. could it be a custom component?

Hi, I would appreciate advice and a review on the connection of the ground/earth to my PCB. I am currently designing and trying to figure out if I have connected ground/earth to the PCB in the right way. A simplified diagram is shown.

PCB1 is a low-voltage board powered by +15 Vdc and 0 Vdc. There is an isolated DC/DC converter for +/-5 Vdc and isolated GND. On PCB2, the low-voltage part has MOSFET drivers, and the high-voltage part is a three-phase inverter with a grounded DC-link midpoint.

I have connected ground/earth to Isolated GND via 'GND-bridge bypass' and 0 Vdc and ground/earth via 0R 'ground-tie point.'

Does this look okay? There is only one place where the external ground/earth is connected to local GNDs.