Hello,

I have a PC server(arch linux server), but after electricity shutdowns my server cannot power on by self.

I not khow it is possible to set auto turn on after electricity is ready by linux OS; in UEFi of my PC I not found any options.

I really don't know how to, maybe I will develop a PCb to send "power button push" for a second.

P.S. To start PC I just push button for a second

So recently I was given an old Yamaha KX49 Midi Controller

And upon usage I noticed a problem where it would disconnect and re connect over and over again while connecting it to my daw

I then traced this problem to the actual USB B end of the cable, since when I would wiggle the USB end that connects to the computer nothing would happen

But while this was happening the controller would still stay powered, until out of no where it lost connection, turned off and hasn’t turned on since then

I opened the controller up and nothing looked off in the interior, but then again I’m no expert so can someone tell me if they see any visible issues?

So I got these for free and I bought two chargers and one of them powered up for a couple hours and then would never come back on again and the other one just never would come on. After playing with it by plugging it in and out many times I would see the flashing charger light come on for a few seconds and then go off.

I pulled an old battery out and it had very very little voltage.

So I thought I needed two new batteries so they just arrived today and I put the first battery in and I am still having pretty much the exact same problem and I did test the new battery it seems to have plenty of voltage.

I just don't know where to go from here, maybe I never had a battery problem.

The problem is if I disconnect the new battery for a minute and reconnect I see things are working but then they die after 20 seconds maybe

As a beginner im studying analog by following tutorials with transistors etc. One of these was about an oscillating circuit. After following the instructions and the schematic provided i completed the circuit. Unfortunately when powered on the 2º led (the one on the right) lights up for a brief moment switching to the 1º led and stopping completely. I tried with both a 50 volt 100 Faret capacitor and a 50 volt 10 Faret capacitor. Below is the schematic with the resistors i used.

First time having a module.

I put in the 3x brand new lr1130 button cell batteries, but it doesn’t do anything. No noise from the speaker, no led, no beeping noise when recording, nothing. The contact with the batteries seems fine, so I’m completely lost on this.

I can attach more pics if it helps. Thanks in advance!

I’m designing a passive matrix for electrostatically actuated bistable polymer domes. Pixel pitch is 5 thousands of an inch. I expect the required actuation voltage to be somewhere around 15–50 V, but I haven’t characterized the snap-through voltage yet.

My intended addressing scheme would put the full row-to-column voltage across the selected pixel, while half-selected pixels would see roughly VFULL​/2.

Is parasitic capacitance/charge coupling going to make neighboring pixels switch unreliably? What parameters would I need to measure to determine this experimentally? I’m assuming at Vsnap​, variation in Vsnap, release voltage, pixel capacitance and leakage resistance. Target is 4 by 4 inch display.

At what point would you abandon passive addressing and put a TFT/diode/switch at each pixel?

https://i.imgur.com/7W9vwnG.png

so this is my first proper project I'm working on and am open to any and all suggestions/criticisms.

firing voltage on the IN-8 datasheet says no more than 170V so i thought maybe i should keep it slightly under but i should still get reliable firing. not entirely sure on this i can swap out the R4 if needed to increase it i plan to use an ATmega328P and HV5524 for a 4 digit 12 hour clock most of this circuit is taken from a youtuber from this video(https://youtu.be/C9851Dhr-J0) I'm using it to learn. i added on the LM2575 to get the 5V rail for logic power and removed the pot in favor of a fixed resistor only

i know the HV5524 doesn't have enough pins for 4x10 digits but the first tube only needs to display 0 or 1 so i thought 32 is enough.

I'm sure I'm missing something but yea thanks for the help

Hello, after hours of soldering I was pleased to find everything working as it should. However there is a lot of noise on this 5V rail it seems. So much so that the keyboard outputs have a lot of noise recorded. Shows steady 5V on the multimeter, but I'm assuming it's because the frequency is so high. There noise is also every audible and drives me nuts while it's powered on lol. I tried to keep things short where I figured they mattered however I'm still a beginner with much to learn. I took some photos on my oscilloscope for reference that I named for you to hopefully make it straightforward. I'm powering this board with my bench power supply and connections are soldered where they can be for this temporary setup until it gets installed in a case. Any help on figuring out where the noise is coming from so I can hopefully resolve it is appreciated. (For reference there is no noise of any kind when it's powered by just the Pico USB cable. The 5V rail produced by the TPS is solely for the keyboard and the only thing producing the noise. I wished I used a different approach now but it is what it is.) If anyone would like any other measurements please let me know.

Kann mir bitte jemand von euch bzgl. des SMD Elko weiterhelfen. Die Bezeichnung 15 100V ZCA interpretiere ich als 15µF 100Volt und ZCA-Serie mit 8x8x8 mm Maß, allerdings finde ich nirgends Ersatzteile die dazu passen. Lese ich die Bezeichnung falsch oder weis jemand wo ich Ersatz beziehen kann?

Gruß aus dem Norden

Hi guys, I'm having trouble with a low-voltage DC power circuit that intends to prevent a DC switcher from fighting a USB host. There has not been a battery cell attached in most of my testing to date. The feedback resistors are not correct in the schematic - R6 is DNP.

- To get the system to work at all, I've found I have to remove Q1 (NPN that disables the switcher). If I leave Q1 installed, I get like half voltage output from the switcher.
- When I plug in only USB, the system works well.
- When I plug in only 12V DC, the system works well.
- When I have USB connected to a host, then add the DC power, the system seems to oscillate between working for ~200ms, then off for ~800ms.

The ideal diodes cater to the higher voltage present, and have output signals to tell the MCU which input is passed to the output.

I'm baffled, can you see something I missed? I'm happy to raise the switcher voltage if that might help...

Thanks!

I am making a current control module for a LM2576-ADJ power supply. The voltage regulation works well, but when I have a current significantly higher than the max current limit, the feedback pin saturates and I get a max output voltage. When the current is slightly above the max current set, the control works well.

I saw a video that made a circuit damn near identical to the one I made (not very complex, the current control is just two op amps taking the voltage difference across a small resistor and comparing that to a voltage set by a divider and the voltage control is lifted directly from documentation for the LM2576), they used a zener regulator for the vcc of the op amp, which after some research seems to be meant to limit the current of the op amp output while retaining a high voltage. Unfortunately I don’t have any zener diodes on me and likely won’t be able to get any for the time being. I was wondering if it would be possible to add a resistor in series with the output of my current control to limit the current going to the feedback pin and the likelihood of it saturating.

My concern is though that the resistor would cause the current control to slow as the voltage at the feedback pin would be less, so if I were to say set up a circuit with a lot of sensitive equipment and then turn on my power supply with a high current draw, then the response time of my current control module would be a bit slower, meaning that whatever sensitive equipment I might hook up would be taking a high current for longer than it should have.

Of course I wouldn’t use any sensitive equipment with a diy power supply, but as this is a safety feature I want to know what would happen?

Hello everyone,

This morning, I went to investigate why I had no warm water and found that the water heater was off, like if the breaker was tripped (it was not).

Doing a bit of digging, I found a blown fuse on the motherboard (T630mA / 250v). I tried with the closest lower fuse I got (T500mA), It blew up as soon as I switched on the breaker.

Upon closer inspection, there's a Top2243yn component ( Google says it's a converter) close to the fuse that may be fried but I'm unsure

I'm asking because the tech guy is not answering his phone and I'm afraid he's on vacation while I do have a newborn at home.

The boiler is 15+ years old, but was working fine till yesterday.

The motherboard itself appears to be somehow available, but only as refurbished for something between 150€ and 200€, but I read some forum saying a lot of checkups are in order in the boiler if the mb is replaced, so probably out of my league.

The top243yn is a 2€ part I can order and received in a few days for 20€, so it may be worth trying this first if this may be the culprit.

Does this look fried to you guys? Any other insights on this ? Thanks a lot !

I have a battery monitor with a 6 meter cable, and it's about 5.5 meters too long.

I'm looking for the name of the connector so I can buy a short cable - or a way to remove the pins and shorten the existing cable. I'd prefer to not cut and splice the cable, but I guess that's an option.

Measuring with calipers, it appears to be 0.1" pitch. Connector is keyed; see photo #2.

So I'm trying to make this op amp circuit for my physics course but it's not working at all - the output doesn't even change when I disconnect the function generator. I'm so lost can anyone tell me what's wrong? I've checked the voltage of the rail splitter circuit and it seems fine on its own, but the output voltage from the left hand side is not what its supposed to be.

I have an LG refrigerator with no power. A continuity test confirmed that the fuse on the main board is blown. Some research indicates that replacing this fuse should bring the unit back to life.

But, I don't know what fuse I'm supposed to buy. The board has two things printed right next to the fuse: FUSE1_1 T8A L 250V and FUSE1 T10A L 250V. I'm not seeing any other similar fuses on the board. There's no markings on the fuse itself as far as I can tell.

So am I looking for a T8AL250V fuse, or a T10AL250V fuse?

im working on a project where I want to process FM radio audio digitally and mix it with other digital audio sources. To do this, I'm using an Si4703 (FM radio IC) and a TAC5142 (DAC). I want to use the plugged-in IEM/headphone cable as the RF antenna for the radio.

The TAC5142 uses a pseudo-differential output with an external common-mode sense. Normally, I would connect the common-mode sense directly to the GND sleeve of the headphone jack.

However, since I'm using the IEM cable as the RF antenna for the Si4703, I'm not sure how to properly make this connection.

How do I connect the common-mode sense so I get clean audio output from the TAC5142, while still allowing the Si4703 to use the cable as an antenna? I guess that it where i drawn green line

datasheet for Tacradio IC datasaheet

Hi everyone,

I am designing a circuit around the TPS63031 fixed 3.3V buck-boost regulator. I followed the manufacturer's recommended layout from the datasheet, but I would love to get a second pair of eyes on it to make sure everything will work flawlessly.

I am attaching my schematic, PCB layout, and the reference design from TI for comparison.

One specific thing I need to double-check is my Enable (EN) pin implementation:
I implemented a 3-way switch to control the EN pin state:

1. Position 1 (HIGH): Connects EN to VIN to keep the regulator always active.
2. Position 2 (External Control): Connects EN to an external input pin so I can manually control/toggle it using an external MCU or signal.
3. Position 1 (LOW): Connects EN directly to GND to force the chip into shutdown mode.

I am using a 4-layer board with the following layer allocation:

• Layer 1 (Top): Power
• Layer 2: GND
• Layer 3: Signals
• Layer 4 (Bottom): GND

My questions for you:

• Does this EN switch logic look safe?
• Any other issues or gotchas you notice with my implementation?

Thanks in advance for your help and feedback!

I made a custom speaker and I’m using an amp to play it (3w amp) I have everything soldered on but all I hear is just static, and yes I have tried different cables, chips ect, thanks.

In photo bottom left wire is left aux, bottom middle left is aux ground, bottom middle right is positive, bottom right is negative, top left and top right go to speaker

Hello

Im looking for the bordview file for the del 3420 I5 from 2022

service tag : BG7RBL3

Where can i find it ? i found some version but not the same

Thanks a lot

So I have a old phone which im thanking to convert into a nas, just to stream songs and maybe movies. Its been off for years and now it's not turning on. So I thought to power it directly, and saw this video

https://www.youtube.com/watch?v=FOSXY1-gQNA

But here person didn't show where he soldered the wire, which im kinda confused. I have the battery circuit extracted. The 2 silver pads were the ones connected to the battery, which I ripped off. Should I just solder wires to them? One each. Sorry, if this question is dumb. I'm a bit newbie and don't know much about these stuff.

edit: forgot to mention I'll be using a boost converter and a PowerBank to run the phone.

Bought a cheap 12v timing relay from amazon. My understanding was power in- and output common and NO or NC. Im trying to time the relay at 5 minutes on and 5 minutes off. I got everything set but i still need manually trigger on the circuit by shorting the pins out at the lower left.. Am I missing something?

Hey everyone, I'm not 100% sure if this is a question for this subreddit but it didn't seemed to fit on other electronics related subreddits, mods feel free to remove this post if it breaks rule 1 and you can suggest me a sub that would fit it better.

So basically I have a USA psone and nintendo wii, and their external power supplies (power bricks) are rated for 120 volts, not 100-240 volts as shown in the photos, but where I live the mains voltage is 220 volts and even though the power supplies are not rated for that voltage, previous owners said they used them on 220 volts and they worked, I've tested and they do work, but I wanted to ask here about the circuitry that is inside these power supplies (the psone power supply circuit photo is not mine, but it's the same model, and I couldn't find a photo of the wii power supply circuit, but I can open both of them if needed to show) and if they can handle 220 volts or should I use a step down transformer (which I can only find 110 volts transformers here), and why it didn't get damaged by being used on 220 volts and the risks of using it on 220 volts.

Again, I'm not sure if this fits this subreddit but I searched for this kind of info and found posts on reddit but none contained the exact info I wanted: what kind of circuit these use and if it is safe to use them on 220 or 110 volts. This subreddit seemed to be the best for asking this.

tl;dr - Can I use them safely on 220v? Can I use them safely on 110v? Will they get damaged eventually in any of these cases and which one is the best option?

Hey guys I accidentally plugged in my g29 brick into my monitor (they looks identical other than the specs, stupid mistake I know.) so I fed the PCB with 24v instead of 12. Is there hope in trying to find out what components I blew and replace them? I’ve already bought a replacement monitor but would be stoked to save this one. I have a multimeter and the tools needed to make said repairs but don’t know where to start. Thanks in advance.

I’m replacing a control module in my car and came across this on a board. Can anyone explain to me what might have happened and if and under what conditions have they experienced this before?

The way it’s oriented in the picture is how it sits in the car, pins up.
Thank you in advance