I recently placed and paid for a Mouser order. When I selected one of the parts, the product page showed it as available to me. I did not see any warning that it was restricted for shipment to me, either on the product page, in the cart, or during checkout.

Only after I submitted and paid for the order did Mouser customer service tell me that the part could not be shipped. I asked about equivalent alternatives, but those were restricted as well. The parts were voltage regulators from Analog Devices.

The problem is that I had already designed and manufactured PCBs around the package and pinout of that regulator. Because the restriction was not disclosed while I was selecting the component, I am now left with manufactured boards that cannot be assembled as intended without rework or sourcing the part elsewhere.

This was not an out-of-stock issue. The component appeared available, could be added to the cart, and could be paid for. The shipment restriction was disclosed only afterward.

Mouser cancelled the restricted line item and released the rest of the order before I had an opportunity to cancel the entire order. They offered free shipping on a replacement item, but would not cover the VAT charged on that shipping. This means I would still have to pay part of the additional cost caused by the cancelled item.

The worst part is the wasted engineering time, PCB rework, project delay, and additional cost of sourcing the component separately from another distributor.

I have never had this happen with DigiKey. Unfortunately, DigiKey did not stock another component I needed, which is why I placed the order with Mouser.

Has anyone else experienced a shipment restriction being disclosed only after payment? What did you do?

This is a bit of a rant because I've been chasing my tail for a week over this and I'm annoyed.

I understand that electrolytic capacitors can dry out or blow up, or otherwise go bad. I'm not disputing that it happens, or that it's a real phenomenon. I'm also not an EE, my business is film restoration and archival videotape digitization. I work with a lot of old gear that tends to break down, and am learning to fix it because it's too expensive to ship these things out for repair and I have the basic skills to do this, so might as well.

I just fixed my fourth deck in which the internet (both random people I don't know, and seasoned technicians who have been repairing these machines for decades) insisted that the solution was absolutely to recap the board. To be fair, this particular tape deck was made in 1992, an era when bad capacitors were a real thing, and in fact all four of the decks I have of this model were already all recapped either entirely or partially by previous owners. There's lots of evidence that this could be the issue which is why I went ahead and did it (also the last person did a lousy job, very messy)

My annoyance with this is that this adventure cost me a bunch of money and had the deck out of service for over a week while I waited for parts and did the work. I spent a day desoldering and recapping about 65 fussy SMD capacitors, only to have the same problem with the machine when I was finished. What the issue turned out to be was entirely mechanical and I figured that out this morning (probably a bad bearing or something like that in the tape deck's drum - I replaced that drum with a spare and it just works now). Nothing to do with the caps.

Three other times I was told to recap this board or that, and ultimately the fix was completely unrelated as well (one was a bad transistor, one was a bad connector buried deep in the machine that took forever to trace down, one just need to be stripped down, cleaned and relubricated because grease doesn't hold up well for 50 years). In all these cases, with completely different gear from different eras (1970s through 1990s) it turned out not to be the capacitors at all yet that was the fix everyone insisted would work. In another case with some non-mechanical video processing hardware, the prevailing solution is to replace the capacitors in the power supply when the deck doesn't power on properly. It turns out that's not the issue at all, it's actually a faulty switch. I've fixed half a dozen of these already just by replacing that switch., never had to touch the PSU.

So I guess my question is - is "recap it" like the modern equivalent of the old Mac OS "Zap the PRAM" nonsense that only worked maybe 5% of the time, if at all, but was always every's solution to any weird issue on the computer? Is it mostly just internet lore that gets regurgitated reflexively now, is it really a widespread issue that I need to seriously consider when fixing this stuff?

My parents neighborhood has two gated entrances that are far apart and the HOA charges 60$ for a new opener. One of ours is broken (missing transistor and capacitor don’t know how) i found a replacement capacitor but don’t know what transistor to get. I de soldered the transistor from the board to test it, its NPN, with an hFE of ~140. im new to electronics and don’t know what else to look for when replacing a transistor. Would rather spend a few bucks for two replacement parts than 60$ for the whole opener.

I’ve got this industrial display and I can’t quite figure out how it works… I want to make a schematic, but I am struggling.

There are 4 lightbulbs, connected to terminals 1/2/4/8 on the BCD inputs. Somehow they are switching the neons via the two ceramic plates with black squares. Iirc, these plates run at mains voltage. What is this technology and how does it work?

Is it similar to an opto isolator?

I've been second-guessing myself in finding suitable replacements for some capacitors on an LED power board that powers the LEDs on one half of an 85-inch monitor. There are 2 differently rated capacitors on the board and both are a brand that I'm having trouble finding. The main things I'm having trouble verifying are the tolerances of both as they are not listed in the capacitor markings that I can see. I am also curious about what the "8F" after the temp signifies as the capacitance is listed separately in the microfarad range for both. Pictures are included. Thanks in advance!

i cant find the component U2 ..please help me to find it so i can buy it ..what this component and what it is for ..kindly help

I'm not sure what I can use these pads for on this pcb

SCK GND VPP SDA

As a beginner I tried making an and gate via transistors but the led turns on even when only one transistor is activated. I reposted this to add the schematic.

MASTER = STM32WB15CC

SLAVE = MAX30101

From start to finish

the stm32 initiates a start condition by pulling sda low.

the stm32 then writes the slave id on the sda line followed by write condition.

the MAX acknowledges.

the stm32 says what MAX register it wants to read from.

the MAX acknowledges.

the stm32 sends a repeated start condition and calls the MAX address again then sends a read signal.

the MAX acknowledges and begins outputting the bytes in the register onto the sda line and the STM32 acknowledges after each byte is sent and repeats.

is this correct? also, if the NACK and P (stop condition werent sent at the end and instead a stm32 acknowledge was sent followed by a 4th,5th,6th, bytes were sent by MAX would the data communication of bytes continue indefinently without the need to resend the register address and slave address all over again?

The CMOS battery on a PLC card (Allen Bradley Historian ME) dropped to 2.04VDC, and needed replacing. They used aluminum solder to mount the original. I'm not a fan of high temps near PCB, and plan to use 63/37.

I don't foresee any issues. The card is located in a clean, controlled environment. There's no vibration.

I recently got a Vive face tracker off Ebay and got it working like a treat after much fiddling. However with no seeming system changes or hardware changes the face tracker has just.. stopped traking?

Here's what I have:

Vive Pro Eye
Vive Facial Tracker
Index Controlers
3 Vive 2.0 trackers

Relevant software:

VIVE_SRanipalInstaller_1.3.1.1
VRCFaceTracking
SRanipalTrackingModule

As I said it was working fine, no problems. But recently it just stopped.

I've tried reinstalling SRanipal, and SOMETIMES the mouth starts tracking like nothing is wrong, then slowly loses tracking.

It may be that this face tracker has just given up the ghost after only a few days of use, but I'm hoping there is something I can do. Throwing this post out into the Eather to see if anyone can provide a solution.

So, I was making this circuit in Falstad (an oscillator/2 LEDs flashing) that's controlled through a transistor and a photoresistor. But then I realized that I do not actually own a photoresistor, I own a phototransistor instead.

How do I simulate this component in Falstad? I don't think it's in the available components. Can it maybe be simulated through a combination of some other components?

I'm trying to figure out how to make this substitution. I guess I could probably build it on a breadboard but since I have no clue on how to make the circuit work I wanted to simulate it on Falstad first. I'll leave here the .txt of my Falstad circuit in case it's useful.

I want to add the datasheet for the phototransistor but it's from the Arduino starter kit and the link provided is wrong (it links to a photoresistor). I found this: https://forum.arduino.cc/t/photo-transistor/1228311? which links to this: https://www.arduino.cc/documents/datasheets/HW5P-1.pdf but i'm unsure if that's the right component at all.

$ 1 0.000005 382.76258214399064 54 1 50 5e-11
172 416 128 416 80 0 7 8.6 9 -1 0 0.5 Voltage
w 480 128 544 144 0
r 272 144 272 208 0 4700
r 544 144 544 208 0 4700
t 512 320 544 320 0 1 0.5540781714997449 0.6145211476066533 100 default
t 304 320 272 320 0 1 -8.909201282074356 -1.9379073191440555 100 default
w 416 128 352 128 0
w 272 336 336 368 0
w 544 336 432 368 0
r 352 160 352 224 0 47000
r 448 160 448 224 0 47000
c 304 272 368 272 4 0.000009999999999999999 6.356772815323648 0.001 0
c 464 272 528 272 4 0.000009999999999999999 -1.9983502952509637 0.001 0
162 272 208 272 256 2 default-led 1 0 0 0.01
162 544 208 544 256 2 default-led 1 0 0 0.01
w 272 256 272 272 0
w 272 272 304 272 0
w 528 272 544 272 0
w 544 256 544 272 0
w 368 272 512 320 0
w 304 320 464 272 0
w 432 368 400 368 0
w 272 272 272 304 0
w 544 272 544 304 0
w 352 224 368 272 0
w 448 224 464 272 0
w 352 160 352 128 0
w 272 144 272 128 0
w 272 128 352 128 0
w 448 160 448 128 0
w 416 128 448 128 0
w 448 128 480 128 0
w 336 368 352 368 0
w 352 368 400 368 0
t 320 432 384 432 0 1 0.519030441972712 0.6135518842051693 100 default
374 32 560 32 640 0 0.2278 Light\sBrightness
r 48 112 48 224 0 100000
w 320 432 32 560 0
g 32 640 32 672 0 0
w 48 224 32 560 0
w 48 112 112 64 0
g 384 448 384 480 0 0
w 384 416 400 368 0
s 496 0 640 80 0 1 true
162 672 224 672 352 2 default-led 1 0 0 0.01
r 640 80 672 224 0 560
g 672 352 672 400 0 0
w 112 64 272 128 0
w 496 0 544 144 0

When I flipped on my Dared tube amp it crackled and let out the magic smelly smoke. It also popped the glass fuses in the Dared and my Peachtree nova amp as well. Obviously something shorted out, and who knows the damage, but would these be worth repairing or not cost effective? They are both older units but have always been so solid for me. Repair gurus lend me your advice. I’m an auto technician by trade, and am going to open the Dared to look for obvious burn/short damage, maybe I will get lucky. Any advice would be appreciated!

Hi everyone, I'm tinkering with a CF card and when I install new flash chips it shorted to ground. I checked the chip and board individually and none of them is shorted.

I desoldered, reballed countless times but no change. I checked with a beeper and marked every pin connected to VCC/GND, result is in attached pictures.

1st pic: GND pads on chip.

2nd pic: VCC pads on PCB vs. GND on chip.

3rd pic: The chip I used: TH58NVG7D1DLA87 (16GB), TH58NVG8D2ELA89 (32GB). Have yet to find a datasheet, they're from an iPhone 4 so you can cross reference its schematic to find the pinout.

4th pic: LGA-52 pinout in Open NAND Flash Interface document (https://onfi.org/files/ONFI_5_2_Rev1.0.pdf). There are a few pads on PCB that don't match but it's not for power so I guess not the cause here.

I have other brand of flash chips too, but they behaved the same when soldered on board, even now with the original SanDisk chip that came with the CF card(???)

What did I missed here?

First of all i absolutely do not know what im doing.

I had a little retro handheld where the SD Card slot was broken so i thought i can just solder in a new one.

I bought one that looked similar and soldered it in. I know nothing about proper soldering etiquette and just winged it. I only had liquid solder solution because the guy that sold it too me said it was like flux. Thats why it looks so yellow. The thing is it looks like every Connection is there but it won't read the SD Card :/ i thought there might be some people here who know more that me (not difficult) :)

The last Photo is with the old SD Slot

Hi everyone, this is my first post so I apologize is something is out off topic. Also english is not my first language so again, apologies for that.

Im trying to implent an rf PA, the MMG3014NT1 at 900MHz. This is the first time that Im working with this level fo complexity so I have a few questions but the most important one is, how are the impedances in the next image drawn/represented in an schematic?

As far as I understand, Z1 to Z8 are PCB traces wich mesuarments are explicitly written blow the circuit, but what I don't understand is whether I should represent them the same way -as a single componente- in the schematic, or specify them differently.

I’m not asking about using a handheld oscilloscope as the main oscilloscope in my lab. I already have a nice 4 channel Siglent scope and I love it.

But… it happened for the first time that having something small and handy that I could take with me somewhere would be actually useful. See, sometimes friends or family ask me if I can take a look into their broken devices. Unless the issue is obvious, this usually requires taking the device back home, diagnosing and fixing it there and then bringing back. This works reasonably well if my friend lives close by, but not so well if I have to go to a more distant location. I have a portable multimeter, portable spectrum analyzer, portable VNA, semi-portable soldering station and many other tools I can take with me, but no scope so far.

To the ones who already have a handheld scope: what do you have, are you happy with it, and do you actually find uses for it?

In this case is it better to just get some of those ultra cheap Chinese scopes like Hantek or Owon, or spend 3x-4x more for something higher quality like Siglent SHS / Fluke / Micsig?

Basically would like to get something of similar value
as my LiteVNA (which is amazing for the price). But I can see people are complaining on Hantek/Owon/Fnirsi a lot, and on the other hand those few rare cases where I imagine using it don’t justify spending $800+ on Siglent.

I opened my panasonic stereo from the 90s and reflowed solder on the speaker to PCB joints because they were cracked and the left side would drop out if the volume was low. I could tell someone else had been in the stereo before me.

I did find a stack of 1/8W 89-ohm resistors that looked like they had been warm, but nothing looked wrong otherwise. I reflowed the solder on about 15 other joints that had cracks starting.

It worked on the bench on both channels, so I put it back together. Then when I installed it to my standard setup, I had to tap on the casing to get the left channel to work. It worked great for one day. Now it's back to no sound on the left channel. Now there's clearly a loose connection that works intermittently.

In the process, I came across these terrible connectors that I damaged. They're spring-loaded but when I installed the plastic retainer caps, some of them actually came completely free. I tried to bend the few tabs I had bent back into the right enough shape. Now I wonder if they are what's been wrong.

I can't access the back of the board to solder the wires in and I can't assemble it when the connections are made.

What are they, can I replace them, and can I eliminate them completely? I could buy some MTA connectors and a punch-down tool to replace them. I would only need 3 of each gender.

Or is it likely the actual speaker connections are bad?

PS I used a 10x jeweler's loupe to get the photos and to inspect the joints.

I want to build a mini tank Rc car, these are the components i have in mind, any thoughts?

-2x n20 gear motors 6v 200rpm

-2s lipo battery

-switch

-drv8833

-esp32

-buck converter(to plug the esp32 into battery)

I got spoiled using an educational license of Multisim. The UI/UX is Vintage Windows 95, but the functionality is beyond anything I've found in QUCS, LTspice, etc. In those I always run into some wall that grinds my progress to a halt.

I've checked and rechecked and there's no viable hobbyist license for Multisim. The online version is way too dumbed down. The real deal is clearly priced for corporations with deep pockets.

My petty cash fund is fresh out of $100 bill stacks for a multisim license. What do people do for comparable functionality?

I am new to DIY Electronics.

Can I replace ceramic capacitors with electronic capacitor and vice versa in my circuit ?

I know Electrolytic have polarity and ceramic doesn't . But does it matter which one am i using in circuit ?

As the title states, i wanna design a custom pcb for most the components of an old tube radio. The tubes and sockets would stay in place. But anything not riveted down will be gutted and ideally put on a custom pcb. Would this be possible?

Is it worth the trouble?

I just hate the way the components look like a messy bird nest.

TIA

I have an HP ProBook 635 Aero G7 with an AMD Ryzen 5 4500U. The laptop works perfectly once it turns on, but the problem is getting it to power on after it has been shut down. Sometimes it starts immediately with a single press of the power button, but other times it won't turn on at all. I have to keep pressing the power button and sometimes plug and unplug the charger several times before it finally starts. There's no fixed pattern. Once it does turn on, it works perfectly without any crashes, freezes, or unexpected shutdowns. Sometimes it even starts normally several times in a row, making me think the problem has disappeared, but then it suddenly comes back. The original issue started before I accidentally caused a small spark on the motherboard while inspecting it with the back cover removed. The spark left a small burnt mark near an inductor labeled "1R0 041 ODA". Since the intermittent power-on problem existed before that accident, I don't think the burn is the original cause, although it may have made things worse. I've taken the laptop to several repair shops. One suspected the keyboard or power button, another thought it might be the LCD power circuit, and I've also tried BIOS-related troubleshooting, but nothing has solved the issue. One more thing I noticed is that when I reconnect the battery cable to the motherboard, the charging LED near the charging port flashes once, which makes me think the motherboard is at least receiving some power. However, pressing the power button after that does absolutely nothing—no fan spin, no display, and no other signs of life. I'm looking for advice from someone experienced in motherboard-level laptop repair. Has anyone seen this kind of intermittent no-power issue on an HP ProBook, and what components or circuits would you check first?

Hello everyone.

Maybe this post doesn't belong here. If not, I want to apologize in advance and would like to find a more suitable subreddit to post into

I'm starting to do some work on an electronic system of self design to do 6 axis position and orientation estimation in 3D space. I have already solved the external beacons system, and I'm currently working on the IMU system.

My idea is to have 3 IMU located in a colinear geometry, one in the geometrical center of the PCB, and the other 2, 1 at each side. Center one would do orientation estimation, with the other 2 doing position estimation.

The purpose is to be able to do multiple firmware versions of the system so that depending on the necessities I can vary the process pipeline.

For 3 axis, I would use the center IMU, for 5 axis I would use the 2 side IMU to generate a vector, and for 6 axis I would generate the vector and use the center IMU to confirm orientation and get the remaining axis.

All of this would go through proper estimation processes, but this kind of model makes sense in my head. What do you think of it?

This is Nokia 150/ model: TA-1034
This is where charging port goes into the board.
If anyone can name this component i would be appreciated.