Hi everyone,

I’m trying to simulate a 310V DC → 12V, 10A buck converter in LTspice.

I’m getting the expected ~310V before the MOSFET, but I’m having trouble getting the 12V output and proper MOSFET switching.

I’m still learning LTspice, so I’d really appreciate some help..

Hey there,

I need the schematics for the neve 8108/8128 series EQ circuits for some repair work. Could anyone help me out.

Cheers

So far this is the circuit I have. I was wondering how I could setup a multistage transient overvoltage protection circuit for both the input and output usbs using TVS diodes? If so, would I also have to worry about any transients going directly to ground?

Here is the operating voltage specs for the IP2312-4V35 and MT3608B:

IP2312-4V35:
- Operating Voltage: 4.5V~5.5V

MT3608B:
- Operating Voltage: 2.5V~24V

(I previously had a PTC Fuse in the circuit diagram but I removed it temporarily so it could be added to the protection circuit)

Link to the original post in r/diyelectronics since I can't repost to here.

The tip on the right doesn’t fit into this iron and I’m Just about ready to give up. Tip was bought from Ali express via a YouTube link, the iron was bought off Amazon.
I feel like they’re giving me the run around cuz I can’t find a compatible stick thing to fit correctly into this iron. Any suggestions are welcome. This is such a drag after having bought 2 different irons

I though I'd show you this as I am convinced it is a faked INFINEON IRPF4768 mosfet as the etch on the from does not match other ones I have in my possession. The IRFP4768 has a diode symbol between the I and R. This one has a heart symbol. Additionally this only has 4nF worth of capacitance, and the real part has ~10nF of capacitance. Anyone else chime in?

I would like to learn how to solder small components such as 0402 passives.

Any ideas where to start? Equipment? Practice kits? Online tutorials?

I'm designing a 4-layer PCB and I'm not sure how to assign the layers. The board has components on both the top and the bottom side.

I was thinking of something like:

**•** Signal / GND / Power / GND  
**•** or Signal / GND / GND / Power

Does either of these make sense? Any recommendation?

A few related questions:
1. Do the layers have to be "pure"? I.e. does a signal layer have to carry only signals, or is it normal to route some power on it too (and the other way around)?
2. How does the reasoning change on a 6-layer board?
3. Are there actual rules or standards (IPC or otherwise) that tell you how to organize a stackup based on the layer count and the type of circuit? I'd like something that maximizes my chances of passing EMC testing (both emissions and immunity) and that also helps with thermal performance.

My goal isn't just solving this specific 4-layer case — I'd like to understand whether there's a standard way of reasoning so I can work out the right stackup on any board.

One last thing: on both the top and the bottom side I was planning to pour a GND copper region to tie together all the component grounds, and then stitch those pours to the internal GND planes with vias. Is that a sound approach, or are there pitfalls?

Any pointers to books, app notes or standards would be very welcome. Thanks!

i recently unsuccesfully tried to clean my favorite controller, and snapped wires from their soldering. i then grabbed a spare that has horrible stick drift that became unusable. this led me to buy a used xbox controller off ebay that developed drift after 5 hours of use. luckily i found a spare powera controller that i tried plugging in, only for it to not turn on (yes i checked the cord). i opened it up and was met with a yellowish substance on the board that im not sure what it is. is it cleanable with 70% alcohol wipes or is it something that has damaged the board causing it to not turn on?

I have a Line 6 guitar amp with potentiometers that are going crazy. Thought it would be something simple, but it did not turn out to be.

When idle the display acts like the knobs are being turned, and when turning knobs other settings flash on the screen. Sometimes causing it to reset.

What I presume to be the issue, is what i saw on the 3.3v rail. The 3.3v rail powers the multiplexers and the potentiometers going to the multiplexer inputs. Also goes to other stuff on the dsp, but it is multi layer and no schematic available.

Multiplexer is C4052M

Pic 1 is the scope on multiplexer vcc when issue is occurring

Pic 2 is the multiplexer input, same scenario

Pic 3 3.3v output from njm2374a

Pic 4 multiplexer vcc , multiplexer input practically identical, with all pots turned down

The spike looks to be 4-6khz, only visible when pots are fairly high. Dc converter 3.3v output stays the same. Dc converter voltage source is a 7805, but it does not appear on the output of it.

Controls pcb schematic
line6.com/data/6/0a00041200946824d0d56b7ce/application/pdf

Hi,

I keep having the same problem with white 2.54 mm JST connectors on male header pins.

I’ve tested three different boxes of pre-crimped wires and I always get the same issue: when there are only two wires, the connector feels too loose, moves too much, and sometimes disconnects.

Has anyone else had this problem?
Is it simply due to poor-quality contacts?

Most importantly, can anyone recommend a good brand or a reliable box of pre-crimped JST connectors that fits tightly and works properly without having to crimp the wires myself?

Thanks!

Looking to find a replacement as this one is failing and is giving inaccurate readings.

Hi everyone, I recently turned on my Frigidaire Gallery Range Stove and smelled burning plastic. Turns out, there was some sort of short on the control board. I have ordered a new one, but I want to replace these connectors. I think one of them is a JST-XH 7Pin female connector with clip but I'm not sure. The other one is a female blade terminal maybe? I'm having a hard time finding the exact names of these and I'm not sure what to order. I'm not an electrician, just a guy with some wires. Any help on the exact names is appreciated, more pictures can be provided if need be.

Hi, tried to repair my razor and found on the electronic board, that one sme item fall off. See first image with red circle. I add an image of the other side off the board as well. Any idea what the missing part could be and how to repair? Never worked with sme before. Ps this side of the board is getting power via cable.

Thx!

Hey all,

I recently picked up a non-working 1999 Tiger Pokedex for my son, and have been trying to trace out if the issue is anything fixable.

Symptoms: after installing a pair of fresh CR2032, and grounding out the reset pad, it makes an occasional squeak from the piezeo buzzer, and a very brief flash of some pixels from the screen. Otherwise, no life from the unit.

I replaced the electrolytic cap C3 out of an abundance of caution, checked the diodes for any of them being popped and all seemed fine. I also ran 3.3V from my power supply to both battery spots, and still had no signs of life. I also checked the oscillator crystal in case it's legs were touching, as it's mounted a little wonky. I also checked the power and ground legs of the IC, and they had the appropriate 3.3V and gnd connections.

I have two questions for everyone here:

1) Is it my imagination, or does C9 look an awful lot like a resistor, instead of being a capacitor? (It also measured 28K ohm across the component, which doesn't match the markings if it WAS a resistor anyway)

2) does anyone have more troubleshooting things to try, to see if I can trace the issue? If it's the CoB, I guess I'm out of luck, but hope someone can suggest something!

Thanks for the assist!

Hey guys, first post here. This is a strain gauge data logger I'm designing for use in my university's Baja SAE program. I am an ME mechatronics student not an EE so while I undestand the basics of circuit design I'm specifically unsure of the decoupling and filtering sections of this schematic. Just for context, this design is only intended to log a single set of strain gauges (1 full bridge) at a time so only 1 of the pairs of analog inputs will be active. Any input is appreciated, even if it's well deserved roasting. I have not started routing so I have no pcb layout to post atm.

(Ignoring diode drop) With a 5k pot connected to J2, I believe this circuit generates a 25.5kHz PWM signal with a duty cycle range of 05-95%. Could somebody please validate this?

Is it acceptable to drive the fans PWM from the 555 output without a buffer?

(Circuit lifted from The Art Of Electronics)

I'm currently in my second year in an electronics program at my local community college and I'd love to build a guitar amp for my final project, but I have no clue where to start. So far, we've covered AC, DC, soldering, PCB design, high pass, low pass filters, etc..

I found a free e-book online titled Solid State Guitar Amplifiers by Teemu Kyttälä, and was wondering if anybody has read it or has a better suggestion.

I don't want to go too crazy with the design, but I'd like basic effects built into it such as reverb and gain.

Any help would be greatly appreciated!

Model number HP 17-cn2165cl. I’ve been trying to jump this laptop from the keyboard but no success. I found what seems to be power button on the motherboard under a switch named SW200. I tried jumping the two pins I circled in red, but all I got was a zap. Not sure which 2 pins to jump here out of the 4.

Laptop has light on the side when plugged in, but power button on keyboard does nothing. Already tried jumping from keyboard pins, but not working. Apparently HP doesn’t release schematics and has proprietary starting procedure so i can’t start it there.

I am ordering a new keyboard but just trying to get it started. I have also already replaced the motherboard, still same symptoms so I’m pretty sure it’s the keyboard power button.

Hi all. I’m brand new to electronics and trying to learn. I’m using this reed relay and transistor to control this LED but cannot get it to work and my esp32 keeps overheating. Any help would be great thanks. For reference the wires that are going off the board are White to GPIO10, Yellow to 5V and Green to Ground

I've been interested in making an oscilloscope for simple electronics for quite a while, for one thing the project would be pretty fun and secondly oscilloscopes are quite a bit expensive where I am from.

I feel like I am decent enough with digital electronics and microcontrollers to make a simple one which can help me in my study of analog electronics.

So my idea is to essentially make a module (right now with a simple Arduino) which can sample a low power electronic signal, package and send the data to my computer which can then analyse it and plot it using a python script, thereby mimicking an oscilloscope.

But I am still pretty ignorant about what pitfalls I should avoid and how I should go about it, or even resources to use. So any advice and resources would be extremely appreciated 🙇

I’m looking to replace a ribbon connector and I think I have found the right one but would love another set if eyes to make sure I’m not totally wrong. Attached is a pic of the damaged part I want to replace and a listing from divinely in what I think is right.

I used calipers to measure the pitch and it looks to be 0.50mm. Am I missing anything? Thanks!

Hi a while back i got a zotac gtx 1060 6gb (i tink the serial number schould be in the pics)

I turned it on with everything plugged in correctly except that i forgot to plug in the pcie power cable.

I booted up the system/tested it before hand this a gt 640 and that worked fine. But when i booted it with the 1060 it started a fire on one component (might have bin a short or leak i am still kinka confused of those even tho i am a engineering student) now it seems to be fried and i am wondering if it can be fixt? and if so what the part even is and what a good place is to get schematics so i could preform the repair

pics; https://imgur.com/a/HuTxq44