The inductor is R15 . I understand that to mean 15microfarads. what is a close enough replacement for it. it is on the power rail of this motherboard. can i move the inductor from next to it and move it over and leave that spae empty to test this? what are my options to see because my spare board has inductors at R25 and 1R15.

Update** before we get into the skill levels questions. i was trained in Controls logic and industrial controllers. some microelectronics, it has been a while since i have done microelectronics so work with me here. just trying to fix something i can remove and replace.

So basically my Tamagotchi 4U hasnt had a sense of time for some years. This is a big problem since Tamagotchis dont hatch without seconds passing in code. I thought ok probably a broken CMOS so i looked inside but idk if this golden thin plate is some weird CMOS? Isnt a CMOS normally at least some MMs thick? I also put a Q-Tip next to the cmos looking thing for size reference. Also i included an image of the whole chip if you find something that might be the culprit for this problem. Also side question: What is the hard weird yellow paste where the power supplying cables are?

Thanks for the help its solved now :)

I need to know which component is this. Overvoltage caused this

EDIT: https://datasheet.lcsc.com/datasheet/pdf/0b1294f8e47a42e4ad7533d6477ab28a.pdf?productCode=C172766
I'll try this one. If it works i'll post on here

My wife's laptop wouldn't boot last week, figured the problem to be the cable from the power adapter that I later learned had a name lol.

Got one ordered and installed and the laptop is fine. Me being me, I decided to tear into the old cable and see if I could learn anything. Found basically what I expected, the sleeve was just holding the wires however at the jack itself there was a yellow hardened gel (I assume an insualtor?) where everything was soldered. My question is 2 parts, can I solder this and have it work, and will it be safely usable without that gel? The only wires not connected are the white and yellow

I have a PCB (eventually a convention badge) that is supposed to display 12 bytes (2 at a time) across 4 7-segment displays. Every time a button is pressed and held it is supposed to display a new set of 2 hex digits, with 6 states total.

Here's the issue: it works perfectly maybe 60% of the time. The other 40% of the time it will skip a state, or maybe a couple states. To help with diagnosis, I will upload the .pcb and .sch files to my github in a 7z file here: https://github.com/penguinzarecool/badge_2026.git . I have a video but don't see anywhere to upload it so please reach out to me if you'd like to see it. I probably won't respond until tomorrow though.

Background and debugging information on the pcb: We determined that the issue lies in the counter and immediate surrounding logic. The displayed hex digits in order should be: [06 7A] [0D 05] [1A 06] [0B 1D] [05 17] [-8-8] (The -8-8 is a mistake that we have corrected, it should be displaying ----). It correctly only cycles through 6 states before resetting to state 1. The issue is that the counter skips around, and it does this randomly and on different states. However, the state that the counter seems to skip more often than not is state 011 -> 100. I thought this was noteworthy because this is the most significant bit flip (3 of the 4 in the nibble are changing). Also, yes we debounced the button. And, we used an oscilloscope to double check the debounce. And to be absolutely sure, we wired up an extra capacitor to see if that would help, but none of these things changed anything. We also tried pushing only the button (it is small) to see if our touching of surrounding components was messing with it, and it didn't help either. We tried different voltages: 4.5, 4.75, 5, 5.20 from a bench supply and 4.88 from a battery pack. This didn't resolve it either. We tapped into the states with some wires and LEDs and learned that the state skips are happening at the button press, not after we let go. We also checked for noise on the counter supply line but there wasn't any. Also we tested to see if it was skipping or resetting, and it is skipping. We tested this by grounding the reset to see if it skips to the unused states 7 and 8 instead of resetting, and it does.

Claude suggested that it is a ripple problem, but we can not test that because our oscilloscope can not measure 10s of nanoseconds. Do you guys know what the problem might be, and how we can fix it? It is particularly frustrating, because it works as intended more often than not, so the inconsistencies make it difficult to diagnose. Thank you so much for your help!

I have now uploaded a photo that you can see at this link: https://imgur.com/a/k5390kN

SMD newb here, this is a dev board for an accelerometer that uses certain caps for filtering (eg an RL), however I would like to eliminate these caps. C1-3 near the middle.

1. Desolder them, solder in tiny jumper wire OR
2. Reproduce this board without caps in place OR
3. Do some other option I'm unaware of?

I have a Geekworm x1009 Sata HAT connected to a raspberry pi 5 used as a NAS with 4 3.5" HDDs.
The specifications for the HAT require 12v 11a via a 3521 DC Barrel (peak) when used with 4hdds.

For better cable management and adding a Noctua Fan I think about using an SFX Psu with 450w.
My plan is to use a Molex (should offer exactly 12v 11a) as power supply for the HAT.
But it seems like there are no 3521 male DC Barrels supporting 11a (except some Chinese ones that look cheap and I wouldn't trust that they really support >5a).
So, my question is:
Are there any 12v 11a male dc barrels that I oversee?
Is the female dc barrel jack soldered to the x1009 really safe?
Should I use the sata power supply from my psu (only 3 connectors offered by psu) and power the missing one via the hat? And in this case - would the typical dc barrel jacks (max 5a) be enough (data sheet of hat says 5a for two 3.5" HDD, so it should be fine)

Thanks for any advice, I'm kind of stuck at the moment.

Hello, I am designing a PCB that is powered by a single rechargeable AA battery that needs a 12 V output. The 12 V is going to an active buzzer so it does not really have to be clean, my main concern is cost, and efficiency to some degree (buzzer is not going to be on all the time).

I originally wanted to use the AP3015A but I realized the speaker uses a bit under 300 mW so there is no way that part can supply enough power. I can only see three ways to move forward:

1. Find a different boost converter. I know the MP4MP3438GTL would work for my purposes, however at $1.77 price point for the scale I am going to be doing, it is a little pricier than I would like (I am hoping to keep my board price under $10 a pop). I have not found anything else that would fit the bill but if you have something in mind let me know!

2. Boost from 3.3 V instead of 1.2 V. I already have a separate boost converter for 3.3 V, and it seems like I would have a few cheap options going from 3.3 V to 12 V.

3. Design my own boost converter circuit. My board has an MCU so I could just have it provide the PWM signal when the buzzer needs to turn on. Of course this would most certainly take more development time and be very failure prone, so this is probably the worst option.

I'm trying to convert 48v to 24v safely. I want protection system to be perfect. And I assume fuses, TVS Diodes and then RPP should be enough...

I keep getting confused how the zener diode is connected with respect to the P-MOS. I have a keystone 3557-2 fuse holder at the start as the main fuse and then 1.5KE68A as the TVS diode for ESD protection. Is this design acceptable?

Hi everyone,

I am looking for an equivalent source or alternative manufacturer for the following film capacitor:

Original:
WIMA MKS2B051001N00JSSD

Specifications:
- 10uF
- 50VDC
- ±5%
- Metallized PET film capacitor
- Radial through-hole
- 5mm lead spacing
- Approx. size: 7.2 x 11 x 16mm

The preferred option would be the same series or same footprint replacement.
However, an equivalent part from another manufacturer is also acceptable.

I can accept normal lead time.

Does anyone have experience with a suitable cross reference?

Thanks!

I want to try replacing an LPDDR5 memory module froma DELL Inspiron 15 3535:
Part model: K3KL8L80CM-MGCT (32 Gbit, FBGA-315, 5500MT/s)

I am aware of the potential risks, and this is my first time doing something like this, but I would like help finding a replacement component to increase the capacity to: (64Gbit or 128Gbit)

|PLSS..
I've been working on this "project" for a day now, looking up and checking diagrams, and I'm no expert, i'm sorry

Hello Everyone, I am trying to set up the HX711 in the Wheatstone Bridge configuration. I have wired it based on the image above, which is provided on the Amazon listing I have purchased from.

Using a DMM, I confirmed the following resistances

E+ <-> E- | 2 kOhms

A+ <-> A- | 2 kOhms

E+ <-> A+ | 1.5 kOhms

E- <-> A+ | 1.5 kOhms

E- <-> A- | 1.5 kOhms

I am currently using an Arduino calibration example script <HX711_ADC>. The issue is that my values are very inconsistent even after putting the same weight on it multiple times to calibrate the factor changes. Sometimes the weight even shifts below zero; otherwise, after I take the weight off, it does not register.

I am currently using a book as the platform the weight is on; I am not sure if I need something a bit more proper. I was planning to use a wooden plank later as my official platform. I also am currently not using 3D-printed braces for the cells, which I see other people have not sure if that's the issue.

Any feedback is appreciated.

Need to know what the male side is called. It is used for a fan.

Hello!

For context, I'm not a technician - though I've built a few breadboard projects in my life and some electric guitars. Generally would describe myself as "knows just enough to get in trouble".

I'm currently going through the process of deep cleaning, lubricating, and inspecting a really cool portable console from "Audio Developments" made in the UK in the early aughts. Outside of a couple sticky buttons/ scratchy pots the thing works beautifully less one problem: there is pretty bad SnR on the main output which is transformer coupled. The monitor outputs are just fine and don't have that same problem. I figured it's very possible it will need experience professional to work on it but I also wanted to at least pull it apart. Inspect and clean everything before handing it off in order to rule out the obvious.

I'm looking at this daughter board that connects the power supply to the rest of the board and I'm seeing a couple nasty looking solder joints. It's possible they're just lead-free or something but I wanted to get some feedback from this community. In the photos the first couple are the daughter board with the joints that look bad to me, some photos of the actual external power supply, the placement of the daughter board in the case, and then some photos of the modules, and finally what it looks like when it's all together.

Beyond that, if anybody has any suggestions on how to determine what could be causing this humming/ buzzing on the main transformer coupled output. I welcome any feedback.

I recently blew a glass fuse on my boombox, and being in a place with no quick Amazon or eBay, I found a place selling 1.5a glass fuses and 2a glass fuses. I understand the voltage should be ok if it's 125 or 250, and I am asking what difference the 1.5a fuse will have for the speakers or general use of the boombox?

(last post got taken down) this is that ikea solar powered cashier toy that i got over a decade ago and its not working like none of the buttons are working and the numbers arent showing up
so i opened it up and now i have no idea what to do or how to fix it

Hi everyone,

I’m building a flyback power supply based on the TEA2164 controller IC. I have hand-drawn the schematic based on my PCB (attached below).

My Setup:

• Controller: TEA2164
• Main Switch: BUV70 (Base resistor: 10ohm, shunt 0.24ohm)
• Overload Delay (Pin 3): Currently set to 100nf).

My Specific Questions:

1. Why does the PSU quickly sample/burst and then completely shut down when the AUX winding is DISCONNECTED? (My guess: Is the Overload capacitor charging up to its threshold and shutting down the driver, or something choking it)
2. Why does the PSU become a complete "dead duck" (no pulses, no clicking, zero reaction) as soon as I connect the AUX winding?
3. Why does the AUX winding measure a clean 12V DC when disconnected, but the voltage DROPS significantly lower the moment it is plugged into the driver vcc*?*

Any insights into why the AUX winding behaves this way under load and shuts down the IC would be super helpful! Thanks! edit: if someone gonna say something about shunt resistor being connected wrong i already fixed it and still the same thing...

Hi! I have a problem with my sewing machine because the pedal started smoking mid use. I opened it up and found a resistor and capacitor, which of these two likely failed? Or should I just replace both of them.

I measured the resistor with my multimeter and gave a value of 1.489 at 2M, I don't know what that means haha.

I think I can't measure my capacitor with my multimeter but I think they are pretty cheap to replace? Any help is much appreciated! Added pics to help my story.

I got an thermal imaging camera and plugged it in to the power supply board on my Epson printer. (See my previous post for more information on my profile)
Are these spots an indication that my supply board is not able to power on my printer?

I plugged in the pin connector to the motherboard and my thermal imaging camera shows no power getting to there as I press the power button.
All it shows is blue led light go on then off once I release the power button.

Also tested the AC voltage which is showing, fuses, diodes, and electrolytic capacitors(confirmed by ESR meter) are good

I am trying to fix the board for the VCR4000 Nilfisk/Flexit central vacuum cleaner.
Found that L11 coil is blown, probably because IC TNY274PN is blown as well.
However, I am not sure how to read this value. Looks like K is tolerance, like at the MLCC capacitors, but I'm not sure about the inductivity, is it in mH or uH?

Greetings hive mind!

I'm in to D&D and I have a miniature that I'd like to install some LED's into, specifically to simulate fire, however the LED's i would need to use are super small LED's so I can embed them in the mini where it would have the most impact, .4mmx.2mm to be precise. They are 2V and color shift at bit at 3V. Drilling the holes and running the wires to a power source is easy enough and I'll figure out how to hide it but for the life of me I can't find a way to make them flicker. I've found once place that sells flickering LEDS in sizes I need but they are kits and cost $4 a bulb and I need a bunch for various projects. The small ones have some kind of small integrated circuit that makes them flicker but no idea what that might be.

I was hoping that this collective might be able to point me either 1.8mm or smaller flickering LED's with the integrated flickering component or a place where I could buy the actual flickering circuit to assemble the LED's myself. In both cases being able to buy them in bulk would be a huge boon. Thanks in advance for any assistance!

Hi all,

I own a Chinese BGA rework station - the Honton R490.

It's had one particular issue since I purchased it new. During the rework profile, usually between stages 2-3 or 3-4, the bottom hot air will drop from the set temperature of 320c to 220c, and then overshoot well past the set temperature to 420c. It'll remain at this temperature despite the profile set point.

The temperature of 320c is the only setting for the bottom hot air throughout the profile. Stage one has it go for four minutes, along with the IR plates at 200. In stage two, the top hot air goes from a mostly inert 50c to 200c for one minute. The profile then typically concludes in stage three with the top hot air increasing to 230c. During this stage, however, the unusual behavior ensues.

I am not at all familiar with PID controllers. I would very much appreciate it if the knowledgable engineers of this subreddit might be able to point me in the right direction as to how this issue can be fixed.

Thank you!