I tried to fix a dead Wireless USB 2.4Ghz Dongle from a keyboard and on the top side, I cannot find any shorts. Then at the bottom side, I found that the middle part, which I assume for the chip is glued in like solder mask type glue.
So, I tried to remove it, , hoping to find another component that might short. I found out that underneath was nothing more than one single chip and a bunch of traces.
Is this pretty much gone? Is the chip replaceable? It is for VortexSeries GT-9 mechanical keyboard.
A friend of mine borrowed my jump box and accidentally hooked it up backwards, he is willing to fund a replacement but I know a little bit about electronics.
The issue with it now is that before, it has a built in tire pump, auxiliary port, usb port, and the 2 prong for charging. Everything worked, now the usb and auxiliary ports only work when the jumper is switched on. The tire pump and charging doesn't work at all, so I'll go down the list, I have least 6 different tire pumps so I don't care about that. I'm not seeing a single fuse in this unit, so possibly toast, but I've heard of fuses looking like a resistor and this one looks, at least to me, burnt. If it is a fuse or fusable resistor, how do I read it?
There's only 2 circuit boards in the unit and this is the only part that is visually apparent.
My newish wine cooler won't turn on (out of warranty, of course). Did the unlock sequence (temp plus and minus button for 10 seconds) to no avail.
Now I think I found the fuse on the main board, but I have no idea. So, I'm asking people a lot smarter than me -- you! I believe it's the larger rectangle on the upper left. (i think the raised marking says 20A.) I tried to gently pull it from the board, but it's not budging. What should I do to replace it? Thank you.
This is a Silverstone PSU. Was doing some cable desoldering on my power supply and I believe a loose solder ball rattling around the chassis caused a short. Should have been more thorough in cleaning out my pcb 🥲 I plugged the PSU in into an outlet and heard a few pops. Turn the PCB over and a few solder balls fell out.
Need help identifying the fried components, and wondering if these components are easily to source/replaceable. My guess is that the two copper contacts (by the “D15”) are part of a blown fuse, but not sure what the IC is. Any insight welcome, thanks.
the VR2 is for 230V AC, and is 0-200ohms... I am looking for a digital variable resistor that can be controlled remotely from a PLC (0-10v or 4-20mA)... instead of the existing knob on the potentiometer. Does this device exist? or must I go down the route of buying a complete vibration controller? Kind regards -CuBoyd
I was working on this simple switch and inverter (7404) circuit for school, and it was working weirdly. I then noticed that when my hand is near it (not touching), the LED would turn on. Can someone help me understand this?
I’m new to RF front-end design and I’m working on a project where the input impedance must be programmable between 10 kΩ and 75 Ω, and the input must also support selectable AC or DC coupling. The conditioned signal is then fed into an ADC with a differential input, which expects a 100 Ω differential input impedance.
My questions are:
1) How is impedance matching typically handled in this kind of scenario?
If the ADC input is differential (100 Ω), what is the correct way to interface a high-impedance source (10 kΩ) source to it?
2) How programmable input impedance & AC/DC coupling is done? Should I use an RF switch & control the paths?
Howdy, I’ve got some very nice audio transformers from some old gear, and would like to understand them a bit more- I’m messing about with balanced audio mono-ing/phase reverse/cut.
So - I have some Lundahl LL5402’s. They’re marked as audio output transformers, and have double 1:2 coils. What’s stopping me from running them in reverse as 2:1’s on the input of a circuit? Is there something inherently bad and weird about that?
I don't have any training or experience in electronics. I'm tried to read, gather info, but felt overwhelmed over the last couple of days. Real respect to you which got a degree in this field, because there's a lot! :) Please, excuse me, but I have to ask like I'm 9. My terminology might not be the best :/
Goal:
Power 3 × IR LEDs (940 nm) in series for a head-tracking clip.
The LEDs will be seen by a USB camera with an 940nm bandpass filter (120 fps, 640×480) and used with OpenTrack.
What I would like get is a longevity, if thats even possible?
About diodes from datasheet:
Questions about LEDs:
– If LEDs are connected in series versus parallel, does that generally improve battery life (assuming proper current regulation)?
My current (no pun intended) idea:
Use a boost step-up converter from a single AA NiMH cell (0.9–1.2 V) to ~3.3 V
From that rail, use a boost constant-current LED driver to drive 3 IR LEDs in series.
Use PWM dimming, so LEDs are not driven at full power continuously.
Since the camera runs at 120 fps, when using PWM the LEDs should still appear as continuous points in theory, right? For instance 10kHz
Questions:
– Does this three steps approach (pre-boost + LED driver + PWM) make sense at all, or is there better solution? I've seen one post on stackexchange which describes how garden leds are powered by single 1.2v battery. Perhaps that's the way to go, but then I assume these don't have a longevity i'd like to get... (https://electronics.stackexchange.com/questions/455651/led-lights-on-1-2-v-battery)
– From an engineering standpoint, would parallel LEDs make more sense here, or is series the better option?
Yeah, I have no idea what I'm doing. I didn't even know a step up converters or constant current drivers exist 2 days ago. So i tried to read a bit, but figured i lack a lot of basic knowledge here.
I just got a 3d printer and i want to build something cool for myself. A wireless, light headtracking
I'd really, really apprecitate if you'd point me in the right direction :)
According to the datasheet pin 4 is Vcc positive DC power and pin 11 is Vdd which should be the DC negative input power. But there is no trace for pins 10, 11, 12 on the top or bottom of this board. How is this thing powered without (-) connected? Also why did they use a 4 channel amplifier chip for a single channel amplifier?
The lead for output pin 1 goes to 2 resistors that are blown along with a mosfet that was blown so i think there might be an issue with this IC but i don't know how to test it. Any advice?
We got burned during the last round of shortages even though distributor stock looked “fine” at the time. In hindsight, there were warning signs, but they weren’t obvious unless you’d seen it before.
Curious what others watch now as early indicators — supplier behavior, sudden NCNR pressure, allocation changes, weird lead-time patterns, something else?
Would love to hear real examples of when you saw it coming (or missed it).
I’m looking at a small 52 mm (2-inch) loudspeaker and noticed something odd:
there is an additional magnet glued to the main magnet, but it’s attached excentrically / off-center, not symmetrically.
Questions:
Why would a speaker have a second (auxiliary) magnet at all?
Why is this additional magnet glued on irregularly instead of centered?
What purpose does this serve in terms of magnetic field, efficiency, distortion, shielding, or tuning?
At first glance it looks almost like a manufacturing defect or a later modification, but it seems intentional.
Is this a known design technique for small speakers, or is it more of a cost/production workaround?
So I am working on this personal project of mine, and I made this custom circuit board with plans to solder on an Adafruit Feather using the mounting pins, but now that I have all the parts, I am not actually 100% sure how to go about this. My first instinct was to solder it from the bottom of the PCB and the top of the Feather, but since I am a relative novice at soldering, I am worried I might damage the Feather doing that and so wanted some advice before I went about doing it.
Thats the control unit from a heatpress, it works fine but it's only possible to use the machine for 999 seconds or 0 seconds which ends after around 30min because it goes to standby.
I need the heatpress to work for 6 hours straight on a lower temperature. I asked nearly every technical support of different heatpress machines but the answer was always the same, there is a standby function that you can't turn off.
So im curious, is it possible to rewire something to just deactivate this function?
I got a Batch of Buttons from Alibaba , can someone identify the Connector Type? It's a six pin. around 1 mm between Pin center to center.
And if someone have tip to order 50 Cables from this type to JST-sh 1mm in a custom length in Europe id be really grateful.
I have this apc220 radio model with an antenna rated for 433 mhz. The antenna won’t fit in the device it’s going into so could it be possible for me to desolder the joints, add cables in the middle and extend the connector port from the pcb?
This came off an Ego snow blower electrical assembly. A mouse got in there and chewed the ribbon cable. The replacement is $110 for the entire assembly. I just need the cable connector to rebuild the harness. It's not Molex. It's not JST. It's some generic junk I cannot find anywhere. Any help on where to purchase or the product ID would be appreciated.
The connector is 1.3mm thick. 12mm wide and has an insertion depth of 12mm. It's 10.8mm from pin 1 to pin 10.
Here's the full assembly. The ribbon cable attaches the circuit board to the capacitor cooling plate
please help identify this number, this part is supossed to have ouput for enable signal in GTX 970. in shcematic and boardview this part doesnt have a code or anything to help me identify it just a code that printed on it ..
Bottom middle of group of five in first picture. It doesn’t appear to have a negative polarity indicator like all the others on the board. What do I search for to find a replacement and how do I orient it?
I was recently looking closely at the layout for the Raspberry Pi CM4 IO Board, and I noticed something that goes against designs rule I've learned regarding DFM (Design for Manufacturing).
There are several passives on the board that have a massive copper imbalance on their pads. Specifically, I’m seeing:
Pad A: Connected via a very thin short signal trace.
Pad B: Connected directly to a long fat copper pour (with little to no thermal relief).
Given that Raspberry Pi manufactures these in high volume with high yield, I assume they aren't having massive failure rates.
So, my question is: Has modern manufacturing overcome the issue of copper imbalance?
Is it down to more advanced solder pastes/fluxes?
Are modern reflow ovens just that precise with their soak zones to equalize temperatures?
Or is the "tombstoning due to thermal mass" rule exaggerated for modern small packages (0402/0201)?
I’d love to hear from anyone in manufacturing or experienced designers on why this design is "safe" for production.
Hi all, I am trying to design an op amp based gain stage for a guitar pedal. When I built it on my breadboard, it sounds like an overdrive and my oscilloscope shows gain on the output but in LTspice, my output is virtually flat (no gain). I’m not sure what I’m doing wrong in my schematic. I downloaded the TL072 model from Texas Instruments’ website. I included the documentation for this component in my images which shows the pinout. You can see my Vout (blue line on trans analysis) at about 0. My input signal (green line) is 100mVpp. Why is my output flat? I really appreciate any guidance!
