I have access to a Fablab's electronic repair equipment but they don't have a micro soldering station, just a regular soldering iron . I'm not sure how fine are the available soldering tips ! is it feasible with a regular iron or do I really need a micro soldering station?

For example on a board with CAN and I2C lines going out of it to communicate with other boards. If the board can take the excess heat is it worth it to use ldo to not deal with the EMI?

If people could give other examples where you may still use ldo instead of buck converter that would be helpful!

Thanks

Hi guys, I'm totally new to this. I want to find another 2 pin connector that is identical to the picture here so I can easily switch them out.

How do I tell what it is and where to buy one?

Thanks!

This is a BW4 battery/solar WiFi camera I’m planning to do some firmware modding to. I need access to the serial console to do so, but the UART pads are in the center of the board. (GND, RX, TX, BOOT) The chip on the board is an Ingenic T23N.

Is soldering the best option here? I am very green when it comes to soldering, so was hoping there was an easier way. I saw [Mini Grabber Test Clips](https://digilent.com/shop/mini-grabber-test-clips-with-leads/) suggested, but those look like they connect to standoffs (?) on the actual chip.

Also, there’s a GND, RX, TX pads on the other side right next to the WiFi chip. That’s most likely for that respective chip, and not the main chip, right?

Thanks!

There are some shorted caps around the second photo IC which is a SN74AHCT367 and everything seems fixable but I still have some thoughts on this supicious burn mark on the Atmel.

I have 2 fixtures with 4 each of these LED COBs. After a recent electrical storm they became discolored. I looked on Mouser and Digikey, but can’t seem to find the match. Any help would be appreciated.

House I moved into had a Kohler Verdera medicine cabinet mirror with embedded lights (similar to https://www.kohler.ca/en/products/mirrors-and-medicine-cabinets/shop-mirrors-and-medicine-cabinets/verdera-lighted-medicine-cabinet-24-x-30-99007-tlc?skuId=99007-TLC-NA ). Unfortunately the connector wire going from power to the lights in the mirror was designed poorly with a straight female adapter. Over time the opening/closing of the cabinet led to stress on the female adapter and eventually the wires sheared (pic 1). We ordered a replacement from Kohler for the part (1481020), but it turns out they made a 2nd Gen that had come out 2 months after my model, and when they fixed the defect by making the connector a right angle, they also changed the size of the connector. The replacement (pic 3) doesn't fit.

Kohler's solution was to give me 20% off an entire new mirror, but I'm not paying $2K+ and replacing a mirror because of a broken wire.

Has anyone ever dealt with something like this? It doesn't seem like the 4-pin adapter they used is common. I was thinking of opening the existing connector and trying to solder the wires, but there was a possibility it would break while opening. Any other suggestions?

Edit: Forgot dimensions!

• Outside thread diameter: 18.7mm
• Inner thread diameter: 15mm
• Connector diameter: 9.5mm
• Distance between from center of one input to another: 5mm (best guess with the caliper I have)

Saw one of these in an old scanner I have, never have seen a capacitor like this before, no luck on google either.

Scanner is a realistic patrolman PRO-10, manufactured around 1977-1980’s according to the chip markings.

The scanner is having problems with clarity, speaker sounds shot and I’m assuming some capacitors could be the issue.

Que tal gente, espero tengan un excelente dia.
Estoy trabajando con una Rog Strix G18, en especifico un componente llamado TAS2781 el cual se averio, lo retire sin problemas con mi estacion de aire caliente, el problema vino al querer limpiar el estaño viejo con malla de cobre y cautin, no logro extraer ese estaño y se me esta haciendo un cochinero, algun consejo?

My Energizer model CHFCV2E AA, AAA, 9V NiMH battery charger started crackling, randomly. took the bottom off and found this, 'round the full wave bridge rectifier. Do you think that glue strip became conductive? Maybe for a moment... Will clean it up & put under test again.

I’m (almost) completely new to all this but ‘long story short’: I bought a replacement charging module for a 9000mah 3.7v lithium battery and once it was soldered on it worked great. I picked it up while my phone was plugged in and charging from the battery and heard a faint pop followed by the smell of burning. Dead board 🙄

I assume I caused a short circuit but I have a couple of noob questions for curiosity’s sake:

1. Neither of the terminals touched any part of the board (I was careful about that) but as I was holding both the board and battery with one hand is it likely or possible my hand/fingers caused the short? Is this something basic that happens enough that you know not to do it?

2. Do you have any YouTube video recommendations for diagnosing exactly what popped? I assume one of those tiny capacitors but I know nothing. This is just for educational purposes and I’ll probably just buy another board from AliExpress as it was ridiculously cheap. I don’t see any obvious black marks from the pop and the battery is perfectly fine- I just tested it. I’d like to know what happened, that’s all.

Many thanks for any and all answers.

Hello tech nerds!

My (35) bf is very interested in doing himself the electronics in the house. He built our PCs and now wants to move on to repairing old phones, opening circuits and stuff (I don't know I'm a literary nerd, pls don't hate me).

As he's only starting, he doesn't have the adequate tools yet. So for Christmas I was thinking about giving him a repairing kit with all the basic tools required for this kind of stuff. But I know literally nothing about it.

Can you recommend brands and/or specific sets that would be nice?

Keep in mind that:

-he is a software engineer and is very curious and crafty, he knows already the basics of electronics (especially PCs and phones)

-i don't want necessarily all the tools needed in each specific situation, all basic tools would be nice as a start

-my budget is about 250 USD or 230 EURO max

I hope my post is OK, thank you in advance! 🙌🏻

Hey geeks, I have an ArmyTek Wizard C2 Pro warm whose on-off / mode selection button has been mangled. I think I have found a button that is a direct replacement due to dimension, construction, and connection styles being from what I can tell identical.

If this replacement button checks out I am going to order it and allow a electronics repair store to replace the button since I don't have the tooling required for this job.

Also do any of you have a resource for ~11.5mm tophat style button caps, I've lost the original to this flashlight.

Here's the replacement button make and model.

C&K PTS815 Sjk 250 Smtr Lfs (https://www.digikey.com/en/products/detail/c-k/PTS815SJK250SMTRLFS/9947849)

So I had a custom board manufactured thats a split F-key keyboard. F1 through F6 on one half and F7 through F12 on the other. Both boards are identical except for the firmware which designates which key presses which. I'll attach a screenshot of the schematics for the board below:

https://imgur.com/a/aIbLTeN

So my issue, I soldered keys to the boards (the keys were the only things in the manufacturing process that weren't available to be soldered on by them), uploaded firmware, then the devices weren't recognized by Windows (Unknown USB Device (Device Descriptor Request Failed)). So I took one of the spares, changed the firmware and uploaded it. So that is recognized as a keyboard but is not recognizing key-presses. I try to upload edited firmware to the board I already flashed, and it can't find the board to do it.

I am just looking for help figuring out what I'm doing wrong. These are CH552 boards, here is the output from Arduino IDE when I uploaded the working firmware the first time here is what it outputted:

usbRertySeconds 2

target: CH552

config bytes: 3

Load file as hex

Loaded 5463 bytes between: 0000 to 15A2

ch375Version 35

CH375GetUsbID 0

DeviceVersion of CH55x: 2.50

MCU ID: 52 11

Found Device CH552

Bootloader: 2.5.0

ID: 13 45 62 BF

XOR Mask: 79 79 79 79 79 79 79 CB

Write 5539 bytes from bin file.

....

Upload complete

When I tired to re-upload firmware here's what I got:

---

usbRertySeconds 2

target: CH552

config bytes: 3

Load file as hex

Loaded 5463 bytes between: 0000 to 15A2

ch375Version 35

CH375GetUsbID 0

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

No CH55x USB Found, retry...

.......

No CH55x USB Found, retry...

Found no CH55x USB

Time limit reached, exit process

Failed uploading: uploading error: exit status 1

I've tried taking my multimeter in continuity mode and bridging multiple spots during the upload which is difficult with only 2 hands mind you and same error. If anyone can help me with this I would appreciate it. I want to get this fixed before I finish printing my enclosure to this becuase I'll have to solder around the case so that it'll look clean on top.

Here is my firmware for the first board (F1-6). The firmware for the second board is identical but for the other F keys. I used Board: CH552 Board, Port: COM3, Bootloader Pin: P3.6 (D+) Pull-Up, Clock Source: 16 MHz (internal), Upload Method: USB, USB Settings: USER CODE w/ 148B USB RAM:

* Pin map (confirmed from the uploaded Split_Keyboard.kicad_pcb netlist,
 * CH55xduino numbering = PortNumber*10 + PinNumber):
 *   Row 0      -> P3.2 -> pin 32
 *   Column 0 (SW1) -> P1.1 -> pin 11
 *   Column 1 (SW2) -> P1.6 -> pin 16
 *   Column 2 (SW3) -> P1.7 -> pin 17
 *   Column 3 (SW4) -> P3.1 -> pin 31
 *   Column 4 (SW5) -> P3.0 -> pin 30
 *   Column 5 (SW6) -> P3.4 -> pin 34


#include "src/userUsbHidKeyboard/USBHIDKeyboard.h"

#ifndef USER_USB_RAM
#error "This sketch needs USB RAM. Set Tools > USB Settings to USER CODE w/ 148B USB RAM."
#endif

const uint8_t ROW0_PIN = 32;
const uint8_t COL_PINS[6] = { 11, 16, 17, 31, 30, 34 };

// Column 0..5 -> SW1..SW6 -> this board's keycodes (left half: F1-F6)
const uint8_t KEYCODES[6] = { KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5, KEY_F6 };

bool keyState[6] = { false, false, false, false, false, false };
bool keyStatePrev[6] = { false, false, false, false, false, false };
uint32_t lastChangeMs[6] = { 0, 0, 0, 0, 0, 0 };
const uint16_t DEBOUNCE_MS = 12;

bool readMatrixPin(uint8_t colPin) {
  pinMode(ROW0_PIN, OUTPUT);
  digitalWrite(ROW0_PIN, LOW);
  delayMicroseconds(3);
  pinMode(ROW0_PIN, INPUT);

  digitalWrite(colPin, HIGH);
  delayMicroseconds(8);
  bool pressed = (digitalRead(ROW0_PIN) == HIGH);
  digitalWrite(colPin, LOW);

  return pressed;
}

void setup() {
  USBInit();

  pinMode(ROW0_PIN, OUTPUT);
  digitalWrite(ROW0_PIN, LOW);

  for (uint8_t i = 0; i < 6; i++) {
    pinMode(COL_PINS[i], OUTPUT);
    digitalWrite(COL_PINS[i], LOW);
  }
}

void loop() {
  uint32_t now = millis();

  for (uint8_t i = 0; i < 6; i++) {
    bool raw = readMatrixPin(COL_PINS[i]);

    if (raw != keyStatePrev[i]) {
      lastChangeMs[i] = now;
      keyStatePrev[i] = raw;
    }

    if ((now - lastChangeMs[i]) >= DEBOUNCE_MS && keyState[i] != keyStatePrev[i]) {
      keyState[i] = keyStatePrev[i];
      if (keyState[i]) {
        Keyboard_press(KEYCODES[i]);
      } else {
        Keyboard_release(KEYCODES[i]);
      }
    }
  }

  delay(20);
}

Asking about the types, not the values (I know that much)

They look like half watt resistors based on size alone. I’m including one pic of them next to a typical half watt carbon comp for size and color reference.

I’m thinking the gray one is probably just a different colored carbon comp, it looks like one in every other way.

The darker colored one has four little holes on one end, that end is also slightly wider than the other. It feels like it is made of a harder material.

I’m mostly curious if these would work in a high heat environment (low-medium wattage tube amp)

These were among a bunch of resistors that I am told were from some kind of computer building or servicing shop.

Hello All,

Ok here's the scenario, I have a micro that is not posting. Powers on and after awhile get the 2, 1 code which is for the cpu. I do all the typical checks, reseat things, power drain, measure my resistances first then my voltages there. Everything is present. Before I go injecting though, I want to take the type and do my first flash. Even though everything is archaic, I wanted to try it out before telling my boss it's time to upgrade the programmer. But from the pictures you see, the IC chip I took from the micro doesn't fit the programmer (both of them) and none of the adapters. I was hoping someone can point me to the right adapter I would need to mount it to the programmer AND if possible I would need the 8 pin adapter as well, for the smaller, more typical bios chip.

Going to eventually get the T48, but for now I have to try to give this old guy a shot before upgrading. I still will need the adapters though. Anyone know what the adapters are called the 8 pin and 16 pin adapters, I would be most appreciative. TY!!!!

Hi everyone!

I'm looking for clear photos or the original schematic of the amplifier board used in the PROEL WAVE12A active speaker, specifically PCB 33000054 WAVE AMP VER.

I'm repairing one and need to verify which components were originally installed, particularly around R12, D5 and R31.

Does anyone own this exact speaker or have access to the same PCB revision?

Even a few close-up photos of the original board would be extremely helpful!

Thanks in advance!

​Hello everyone,

​I am currently working on repairing an ASUS ROG Zephyrus G14 (GA401QM rev 1.6) motherboard that suffered power-related damage.

​After restoring the main power rails, I am facing an issue with the USB-C Power Delivery subsystem. The TI TPS65994 PD controller and its companion CAT24C512 EEPROM seem to have corrupted configuration/firmware data (Type-C ports are not negotiating power or working in alt-mode).

​Does anyone happen to have a known-good working binary dump (.bin) for the CAT24C512 attached to the TPS65994 on this specific board revision?

​Hardware details:

​Laptop: ASUS ROG Zephyrus G14

​Model: GA401QM

​Board Rev: 1.6

​Target IC: CAT24C512 (SPI/I2C EEPROM for Type-C controller)

Number U4603 on board view ​Programmer available: CH341A / NeoProgrammer

​Any help, a raw dump from a donor board, or advice on configuring the TPS65994 via TI Application Customizer for this specific laptop model would be greatly appreciated!

​Thank you in advance.

It works fine. Just want to make sure I'm not causing any damage. The wiper is connected to the LED strip and the one side to 20v. The light never goes completely off but I don't need it to.

I tried attaching the other side to ground and now the LED goes off at about half way. The dimming isn't very smooth but good enough.

What I'm wondering is...

* When the LEDs are off, am I shorting my battery?

* If I move the 20v to the wiper, would it make much difference? I've not tested because (see first question) would this put me at risk of shorting the battery.

* Will a 1k ohm resistor on the ground solve all my potential shorting issues?

Hope this is OK in this group. Didn't really seem like it was strictly a LED issue. Feel free to come at me with formulae I should learn!

Hi everyone,

I have a GD32E230C8T6 MCU and I'm looking for a suitable, affordable SWD programmer for flashing firmware and debugging.

Has anyone worked with this MCU? Which SWD programmer and software would you recommend?

Any suggestions or firsthand experience would be appreciated. Thanks!

Hello everyone.

I'm developing a device to detect the presence or absence of 220/230 V AC (50 Hz) using 15 to 18 inputs connected to an ESP32.

I'm looking for a circuit with the following characteristics:

Galvanic isolation.

3.3 V digital output.

Low heat dissipation (ideally less than 100 mW per channel).

Reliable detection, without false triggers due to induced voltages.

24/7 continuous operation.

I've been evaluating H11AA1, PC817, Darlington optocouplers, and ISO1212, but I'm concerned about the heat generated by the current-limiting resistors when using so many channels.

I found the Wiren Board WB-MCM8HV as a reference, which uses approximately 0.3 mA per input at 230 V AC, although its circuitry is proprietary.

What topology or components would you recommend to achieve reliable detection with such low power consumption? Would it be better to use high-impedance resistors, capacitive limiting, or some alternative circuit?

If you know of any schematics or projects you've tested, I would appreciate it if you could share them.

Thank you very much!

Hi everyone,

I am simulating a power supply circuit using the LTC4417 power-path controller and LTC3111 buck-boost converter in LTspice. The output voltages appear to be correct, but I am observing a large negative input current spike when the power source switches.

Circuit details

• Power source V2: 7.4 V
• LTC4417 output (V(4417_o/p)): Approximately 7.4 V
• LTC3111 output (V(3111_o/p)): Approximately 5 V
• Output load: 1 A constant-current load
• Simulation command: .tran 10m

What I observe

When the power-path switches around 3.646 ms, the simulated input current through V2, measured as I(V2), briefly drops to approximately −10.63 A. After the transient, the current settles to a much lower value, depending on the operating conditions.

The current spike occurs over a very short interval, while the output voltage eventually settles to the expected value.

My questions

1. What could cause this large negative current spike in LTspice?
2. Are there any recommended LTspice settings or modelling techniques for accurately simulating the LTC4417 and LTC3111?

The output voltages look correct after the transition, but I want to understand the cause of the current spike before proceeding with hardware testing.

I have attached the schematic and simulation waveforms for reference. Any suggestions or explanations would be appreciated.

Thanks!

Searched it on google and says 2.2uF 10V. Can anyone confirm if it's correct? Thank you.

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.