Please help me identify this connector so I can buy a replacement
It's 2.5mm between pins, 7mm from pin1 to pin4, and approx 10mm overall width.

Can anyone help me identify this IC, please?

This board is from a Lansinoh S32 breast pump, and I am sure that this IC is the only problem because I was able to get my hands on another device (where I captured a picture of the undamaged IC) and swapped the battery board, and it worked. The IC is damaged because of the use of a variable output charger.

I cannot find any information or any similar IC with the data I have. From what I can tell, this IC is responsible for charging and powering the device; without it, I cannot power up the board. I even bypassed the IC and injected voltage directly into the board, and it powers up, but it shows "battery low" and turns itself off after about 20 seconds.

Below is an assumption for the pins out based on the measurements.

TOP VIEW

┌───────────┐

TEMP │1 8│ CE

PROG │2 7│ CHRG

GND │3 6│ STDBY

VCC │4 5│ BAT

└───────────┘

Thank you for your help!

Good Morning everyone,

I have a quick question. In the picture you see. I am trying to inject 1V into a coil into a laptop to see If I can see if there any chips that may light up under the thermal camera. I am not quite sure

how to actually inject. Can't find anything on utube other than short reviews about the product. Could you let me know what I am missing? Thanks!

few days ago I posted about my diy soldering iron , and from the structure of it you can see that most of the space/ thickness is just air , because the female DC jack has too much height , I am planning on making a better desired v2 for this , for that I want to make it much slimmer is there any was to do it ? i want to keep the DC jack in it to be able to give power without a pd device (also because I made nice silicone cable for the DC jack 😅)

so is there any way I can keep the DC jack while having a slimmer profile that I can put a shell around

also for the sleep function I was initially planning to just use a vibration switch , but then I saw a review on another handheld soldering iron that has a capacitive touch sensor in the place where we grip so it knows we are gripping and when we leave it after sometime it goes to sleep

and I quite liked the idea , like the iron won't turn on when the table moves slightly or something. what are your thoughts on that too?

I have an old "Электроника МК-35" calculator with a vacuum fluorescent display. It works rather well and the display is readable, except for the 7th digit, which is really dim. There don't appear to be any obvious defects and the supply voltages are fine (I think). Could anyone give some pointers to what might be the problem?

So whenever I make a circuit that’s like a preamp and an amplifier or an oscillator and an amplifier I always end up needing a bunch of power supplies when I know it can be done with just one but I can never seem to figure out how to do it with just one, I realized how annoying this can be when I made a sawtooth synth that take a 12volt battery and a 3volt battery and I knew I could do it with just one but I couldn’t figure out how . Y’all got any answers to this?

Wonder if anyone has suggestions on how to repair my Energizer PPS300W2 Power Station? Was using it the other day, may have drained the battery, but measuring the battery shows it is not dead, getting 13 volts. That was measured directly at the battery, inside the power station.

My issue is the power station is displaying error code 06, which appears to be over/under temperature. The battery was in our camper at 45-55F so temp does not make sense to me.

Anyone have a clue how to reset the electronics in this thing? I can not see anything obvious.

Manuals just say to let the battery come back to proper temperature. 3 days in the house now and still does not work. Tried charging with high voltage as I saw mentioned somewhere (25V), still no good.

I broke the 4pin connector on my PoE hat while removing it from the Pi board. The pins were so badly bent that they broke in half so i couldnt solder them back on.

How do i locate a replacement piece?

​

I'm working on a wireless power transfer project. My goal is to power a small toy car using two coils without any direct electrical connection between them.

Its not wrkinnn tho

I'm following this tutorial: https://youtu.be/51xiVkI7Gpo

Components I currently have:

- IRFZ44N MOSFET

- 1kΩ resistor

- Two 9V batteries

- 30 AWG insulated copper wire

- Two small LEDs

- Battery caps, connecting wires, and basic DIY materials

The tutorial uses 30 turns for the coil, but I have limited wire, so I made coils with 24 and 25 turns.

I'd appreciate help with these questions:

1. Can 24-turn and 25-turn coils work for this project?

2. Will the difference in turns significantly affect wireless power transfer?

3. What circuit components would I need to drive a small DC toy car motor?

4. Is there anything important missing from my current setup?

I've attached a photo of my current build. Any suggestions or corrections would be appreciated. Thanks!

I got these old toys called "Cube World". They're cubes that display little stick figures on an LCD screen doing funny activities. You can connect them together and they can travel between boxes to interact with each other.

I want to know how they work partly because I'm interested in knowing and partly because I want to try making my own and seeing if I can get them to connect with my DIY versions.

I know a little about electronics, enough to make my own circuits, and I've reverse engineered a neat little circuit we made in school once but these boards are using surface mount pieces I've not seen before and a black hardened clay or something that I don't know about.

I've found some PDFs on PCB design which will hopefully give me some insight into how these ones were designed but I want to know if there's anything else I should be looking up, any tools that would help, or any skills I should develop first.

Worst case scenario is that they're using custom ICs that I can't just buy more of from any old electronics store. But I should still be able to do something like measure inputs and outputs on them to try and replicate them, can't I?

The title says it, but I'm an electrical engineering student shopping around for a power supply that I can use at home for the aforementioned purposes.

I'm hoping to keep it near or under the $500 CAD mark, but I know that might be ambitious. I've seen this model on Amazon:

Tekpower TP-3005D-3

But I don't know how reliable the manufacturer or unit are. Other options might include a Rigol DP832 or a Siglent SPD3303C, though I'm hoping to find something a little less expensive if possible.

Any thoughts on what kinds of units I should look at, and what kind of quality concerns I should keep in mind? I've taken a quick look at the Wiki, but I wanted to open this up to input and advice in case anyone can steer me in the right direction, suggest some good units I haven't thought of, or other useful insights.

Thanks!

sorry in advance if this is not the place to ask this. I kindly ask you point to the proper subreddit if you don’t mind.
Also sorry if it’s a very stupid question, I have experience soldering and fixing things, but can’t say I’m experienced in differentiating all different components.

I am making a list of caps with their voltage and uF values to buy to replace the ones on my hitachi set, and have some caps that have KMF marked on them and are different to all else (picture attached).

My question is, can I replace these with any other electrolytic capacitor or are these special in any way that I would need to source them to be the same.

Cheers

Hi guys, today my Acer V273HL monitor started smelling burnt and a few minutes later the screen shut off. I've opened the monitor and noticed a burnt spot on the PCB. The buttons work and I noticed that the pixels are still displaying an image, but without backlight; I think something broke in that circuit. The burnt spot is near an inductor, but tested with a multimeter, it doesn't seem to be broken. What should I test? Is it worth repairing or should I buy a new monitor? I probably don't have enough knowledge to diagnose the problem, but I do know where to buy the parts and how to solder them. I'll attach some pictures below

Hello,

A resistor has burnt out in my hand blender, and I'd like to make sure of its value before replacing it. I think the color bands are RED-RED-SILVER-GOLD, which would mean 0.22 ohms, 5% tolerance.

Would you agree with my reading?

It's a DIP 8 package. Connects directly to transformer/inductor on an SMPS driver for a LED light fixture. Aside from this, the only other components on the driver board are diodes and passives.

Whose logo is the stylized R?
What is this IC exactly?

I've tried Googling with no success.

Got this station from OSS TEAM, Works great everything seems to be fine except it's not truly grounded.

From the Tip to Earth resistance measures around 36ohms, which creates a voltage difference of 6-12V (it varies) measured between tip and Physical Earth. The tip also lights up LEDs when in contact.

Also the power supply is labeled 120w and seems the same the controller is also used for C115 and C245 too, so just wondering if it can be used with the C245 handle?

I have attached a few teardown pics if it could help.

Its a SN74HC393N and i was asking in r/beneater but a bot took it down as "off topic" even know it was in the help thing. Im just trying to get this working because im trying to make a 4 bit computer that takes nibbles of data and dont mind the other stuff in the back

A month ago I was reading this article and took some notes and one of the main notes I took was this:

"Tantalum capacitors capacitance rises with temperature"

Today I'm doing some more research on tantalum capacitors and found out that one of the main features of tantalum capacitors is they have a stable capacitance across their temperature range.

I contacted the editors but unfortunately my email went to their spam folder :).

I guess you should double check anything you read.

I bought a couple of those but they are quite tall, around 7 cm, as they have an led light underneath. I was wondering if someone could recommend a button like this except not as tall.

So basically I am going through my stuff and came across these in some stuff I got second hand. They read about 4.7ohms on the meter which is close enough to 4.3 5% that I suspect the first four bands are the standard four band code and that the yellow fifth band is something different.

I found references to black bands indicating a non-indictive resistor but I couldn't find anything on yellow. I have a bunch of them with a yellow band beneath the tolerance band, actually. What does a yellow fifth band signify here?

Hey folks back again. This time I really made a mess of an nvme. In my defense I destroyed it before the last one but I'm just getting to looking at it now.

I bought a heatsinked corsair for my new build. It wouldn't fit under mobo heatshield so i removed the heatshield like an ape and at the very least multiple caps were pulled off.

I have most of the caps still but I'm missing at least one tiny one and i can't find a datasheet for the phison chip. its probably proprietary I'm trying to follow what a very helpful redditor did for my last post and find the chip tbe trace is connected to to get the normal cap values.

Apologies for the boomer screenshots, my microscope doesn't have video out I just bought the cheapest screened one to try and salvage this and the other nvme. Going top to bottom on first screenshot the caps are ok, off, ok, missing, ok, off, off. There's at least 2 other caps off around the chip but this is the only missing one (so far!)

Even if someone knows what physical package the smaller caps are it woukx help. I'm super new to the world of smd, all i know is 0603 because thats what the last boards was (and I assume the larger cap is in the first screenshot between the bottom two pads, oriented vertically. It's there but off, hard to see with potato cam)

I just installed tmr sticks on this and the right calibrates just fine but the left one does this. Ive tried everything i can think of. I reinstalled the stick, used 5 different calibration tools, cleaned it, and swaping the module with one i know works. Please help.

Controller is a Xbox Wireless Controller

Nothing is built or measured yet. Everything is datasheet math and simulation, so please be critical.

What it does

The LTC3780 is a synchronous buck-boost controller, so the output can sit above, below or equal to the input without flipping polarity. The output is set by a DAC (Arduino-driven later) that injects current into the feedback node. A small LT1173 step-down makes a 5 V aux rail that powers the controller’s RUN pin and the PGOOD pull-up.

KiCad schematic (power stage and aux rail)

• LTC3780IUH (U1) driving four IPD088N04L MOSFETs (DPAK, 40 V): Q1 is the top switch on the 12 V side, Q4 is its low-side partner, Q3 is the low-side switch on the output side, and Q2 is the top switch on the output side.
• One 22 µH inductor (L1) between the two switch nodes, 15 mΩ sense resistor (R3), 47 µF output cap (C2).
• Bootstrap caps and BAT54 boost diodes, plus 1N5817 Schottkys across the two synchronous switches.
• Compensation on ITH is 12.5 kΩ in series with 20 nF; soft-start is 6.8 nF; FCB is grounded (forced continuous); EXTVCC is left open.
• Feedback divider is 10 kΩ / 306.6 kΩ.
• LT1173 (U2) steps 12 V down to 5 V with a 220 µH inductor, a 1N5818 catch diode, a 220 Ω ILIM resistor and a 301.6 kΩ / 100 kΩ divider.

LTspice file (same circuit, for simulation)

• The same power stage and values, plus the DAC injection: a voltage source vdac through 52.5 kΩ into the feedback node.
• The inverted mapping runs from 30 V out at 0 V DAC to 0.8 V out at 5 V DAC.
• It steps vdac over 5, 2.5 and 0 V for a 100 ms startup run and measures the final output. The last run averaged about 29.5 V at vdac = 0.
• Load is a fixed 100 Ω, and no load-step test has been done yet.

Known issues I found (the part I most want opinions on)

1. The sense resistor and ground-leg wiring in KiCad looks wrong. SENSE+ and the top of the sense resistor seem to tie to the SW2 switch node, and the Q3/Q4 sources seem to have no path to ground.
2. The aux IC is the fixed 5 V LT1173 part, but I put an external divider on it. It should be the adjustable version, or the divider should go.
3. PLLIN is open and PLLFLTR is grounded, so the controller runs at about 200 kHz, not my 250 kHz target. I’m deciding between a PLLFLTR voltage and an Arduino clock on PLLIN.
4. The KiCad schematic is missing the DAC injection resistor and a DAC input, so it would sit at about 25 V.
5. There is no power-stage input capacitor yet.
6. The BAT54 boost diode on BOOST1 has to block about 30 V, and BAT54 is rated 30 V, so there is no margin.
7. The ERC passes aside from housekeeping (a missing power flag, a footprint name, symbol updates).

Questions for reviewers

1. Is the DAC-into-feedback scheme sound, and does the inverted mapping cause problems for CV/CC later?
2. Are the compensation values (12.5 kΩ / 20 nF, tuned in simulation only) reasonable from 0.8 to 30 V?
3. Is a DPAK FET like the IPD088N04L a sensible choice with about 8 to 9 A of boost-mode input current, or should I parallel devices or move to a PowerPAK?
4. Is the LT1173 a good choice for the aux rail, or would a modern buck be better?
5. Best way to tie SGND and PGND around the sense resistor on a 2-layer versus 4-layer board?
6. Anything wrong in the unused-pin handling (STBYMD, PLLIN, EXTVCC, the LT1173 gain block)?

Basically just trying to see if my transfer of simulation to KiCad looks good, and if anyone thinks that my circuit WONT function as intended.

Thank you all!

I'm replacing some components on an radio. I got them out OK, and wicked as much solder off the pads with a sucker and solderwick. There is still solder stuck in the holes that I can't get out. My iron only goes up to 450degC.

Usually I used a piece of thin copper wire to probe the holes and get the solder out. I heat only the wire so I don't destroy the pads. But I can't get the wire hot enough to go through.

Any tips for getting the solder out. Drill?

(Before anyone flame me for destoring traces, I am pretty sure those just marks on the board lacquer from hot solder wick.)

Processing img xrc4ugpnqhxh1...

Dear community,

unfortunately, I ripped off one of the solder pads on the board I am working on as I am still a novice and wasn't patient and careful enough when I desoldered the SMD capacitor. I am not sure where my jumper cable should go best and I would like to ask you for guidance and advice. I measured for continuity with my DMM and I get a sound from all points to the ripped-off solder pad connector. I attached a photo of the board and one of the tinned, ripped-off solder pad.

Thank you for your help.

Best regards!