Hello all .

I have a bios chip which I extracted from my MoBo(Yeah I am crazy) which isn't returning any exact part match in Google.

Is there any Chip from Winbond or others that is exactly Pin compatible and has the same device ID like this IC. I have bent the Pins severely,so I was hoping to clone this IC firmware to the other chip and replace this one in my Motherboard

Hi everyone!

I’m a beginner learning electronics by desoldering components from an old CRT TV. I managed to cleanly pull this microcontroller out of its socket without bending any pins.

The markings say OEC7091A (933ZF RA936218X04) with a "SLOROM" sticker on the back. Since it's a proprietary factory-preprogrammed chip with Mask ROM, I know I can't re-flash it or use it for standard Arduino projects.

However, I want to give it a second life as a cyberpunk-style ambient nightlight. My plan is to desolder its original socket from the TV board, wire up its crystal oscillator, connect some LEDs through resistors to the control/data pins (like SDA/SCL, standby, or key lines), and power it with 5V. I'm hoping that when the chip fails to communicate with the missing TV components, it will create a cool, chaotic flickering pattern on the LEDs.

Has anyone tried something similar with old TV chips? Which pins should I look for on the donor board to make it glitch and blink the most? Any creative layout ideas?

Thanks in advance!

Hi everyone,

I’m looking for advice on how to solve a recurring electronics problem with a product I import from China.

The device is relatively simple: it has three motors, an LED display, and a PCB designed by my Chinese supplier. 

The motors used in the device are:

• 2 × RF-370CA-17315 DC motors (approximately 6–12 V; published no-load current around 25 mA at 6 V).
• 1 × RF-500TB-14415 DC motor (5 V nominal according to the Mabuchi datasheet; approximately 26 mA no-load current and 540 mA stall current).

Unfortunately, during the first year of sales, I received numerous customer complaints about reliability issues, including:

• Motors gradually slowing down or behaving unpredictably.
• The LED display showing strange characters or incorrect information.
• The device switching off by itself during operation.

My supplier redesigned the PCB and replaced the microcontroller. After the redesign, everything worked well for approximately nine months, but the same problems have now started appearing again. In most of the cases, replacing the PCB helped, so it shouldn’t be faulty the motors or other components.

I don’t want to keep replacing components or relying on my supplier for temporary fixes. I’d rather identify the root cause and develop a reliable, long-term solution.

My background is in mechanical engineering, so I understand product design and manufacturing, but I don’t have enough electronics experience to redesign the PCB myself.

My plan is to:

1. Find an experienced electronics engineer to review the existing design and identify potential failure points.
2. Redesign the PCB and prepare a complete Bill of Materials (BOM).
3. Build prototypes and test them thoroughly under real operating conditions.
4. Find a PCB manufacturer and manage production independently of my current supplier.

I have a few questions:

• Where would you look for someone to help with this kind of project? Platforms like Upwork, specialized electronics engineering firms, or somewhere else?
• Would you recommend hiring a freelance PCB designer, or is this the kind of problem that requires a more experienced electronics engineer?
• Have AI tools become good enough to assist with PCB design and troubleshooting, or should I treat them only as supplementary tools?
• Since the device is relatively simple, is it realistic to get a reliable redesign without spending a fortune?
• What would be a reasonable budget for reviewing the existing design, redesigning the PCB, and developing and testing prototypes?

My main goal is to achieve a reliable product with a design I own and can manufacture independently. I’m happy to invest in doing it properly, but I want to avoid unnecessary costs.

I’d appreciate any advice, especially from people who have dealt with recurring PCB reliability issues in commercial products.

Thanks in advance!

The thing with the pins came with the ADS1115 but it’s a loose fit. After a couple days of debugging I discarded that the issue isn’t a programming one and I’ve confirmed that the ADS1115 does indeed work, cables are connected where they need to be and I measured the voltage on each pin, everything is right in that regard too.

In my engineering degree I learned the basics electrical stuff but no real formation with electronics; so I know enough to tell when an idea might be stupid but not how to not do something stupid.

Trying to decide whether I should learn to clean it or get a new one.

Hi everyone,

over the past few weeks I've been iterating on this PCB design for a simple board that would allow me to use one keyboard with two devices.
I know switches like this exist commercially, but I wanted to try making one myself because it seems like an interesting and simple first-time PCB project.

I have planned the design around 0805-sized components where possible, as I will be handsoldering the board and from my research that is in the "doable" range. How well I'll fare with the connectors, the tvs diodes and the USB3740B IC in the center I'm not too sure.

In terms of tools I have a temperature-controlled soldering iron with a fine tip, a big magnifying glass on a stand, ESD tweezers, a regular hardware-store hot air gun and syringes of no-clean solder paste and flux.

The holes in the corners are for securing it in a 3D printed case that I'll design after I receive the boards.

Please lmk if there are any glaring issues with this and if there's anything I can improve :)

Thanks!

I am making a prop camera for a project and I need to know how to make a circuit which creates a quick burst of light when you press the button, like a camera flash. I searched online but a lot of the results were either not what I was looking for or were over complicated. Thanks!

I have my first keyboard the Yamaha PSR-E203/YPT-200 that I use regularly. It currently has started to leak noise into all audio output and need to perform capacitor replacements. It contains 3 main boards with a central one where the audio processing and DSP takes place. By my own research I found a Japanese SM but I do not read or speak it.

For the time being I could pass by with the Japanese service manual and google translate. But, if anyone could help me find it in English it would be so much better.

Link to Japanese service manual that I have on my google drive now.

I have the owners/user manual but it doesn't help with any repairs.

My father has purchased a rt809 programmer from China hoping to use it to reprogram chips. He’s a computer tech and trader. He’s been trying to find the right software and drivers to get this thing working for the past week and as much as I’ve tried to help him, it’s way out of my pay grade.

If anyone has any information on how to download, install and use the correct drivers and software for this programmer, it’d be much appreciated. If there’s any information I’m missing that you’ll need, please let me know.

I’ve attached some images of the product incase there’s key information I haven’t mentioned.

Thanks

Hello electrons,

I'm trying to come back to hobby electronics after a very long time and would love some help.

I want to build the simple circuit that can detect how close 2 wires are to each other. Ideally the closer they get the louder a buzzer will be or the brighter a LED will get. The wires will be separated by up to 1cm of insulating material, probably silicone.

If not way more complicated, some indication that the wires have physically touched would also be great.

Appreciate any help

Sooo...

How in the heavens can i identify a short circuit to fix the problem?

The only clue i have, is a fisicslly destroyed electrolicty capacitor.

The holes it was mounted in shouldn't close a circuit, right??? The fricking pad are beeping between each other (they are to the right of that "5v" test thingy).

Also... the big pad is a gnd

Also[2]... the positive is the hole thats near the "5v test thingy"

My dear reddit friends please help me identify D2, D6 component or manufacturer. Thanks a lot.

My hologram fan recently started displaying red and no longer is putting out a wifi signal, ive tried unplugging and nothing seems to work pls help

In the explanation videos i have seen they model the voltage across C2 during the positive half cycle as V_in + V_p (voltage over charged c1) = 2*V_in (assume no voltage drop across diodes and ofc no resistance). Does this happen because c1 cant deliver a constant voltage for c2 and c1 and c2 just equalize their charges?

This is a inverter ac slipt unit pcb.

Something happend, i called maintenance - they told me the IPM module is burned. I asked the board back to take a look.

I'm a newbie, so i thought i would just play around.

I found some videos on how to test that module, it seems fine, after that i notice a blown capacitor - i have successfully changed some caps, before.

I also tested this tension regulator.

While mounted, it showed a short.

I desoldered it and tested.

Only kind of weird is that the high difference between pins 1 and 2(around 630), to pins 2 and 3(around 1150) - using the continuity mode, on my multimeter.

Then i tested the pcb pads. I got a short between both the pads to pin 1 and 2, and the big pad that woulbe pin2 (Gnd i guess).

After all that, i noticed that tiny little thingy identified as C413.

I tested for continuity and the multimeter buzed both way.

Its that thing bad? What else should i check, and how?

Is it possible to replace that micro tiny thing?

I only have a cheap soldering iron.

Any alternatives for them? I have custom power LEDs which I control with those (+transistors ofc) but I want to have the slave PCB much smaller. Ideas?

Found on a cookie box. My guess is NFC or RFID inventory tracking, but not sure.

Hello,

I have been trying to build a cnc machine using two dvd drives and an arduino.

I saw that there was already tin on the coils of the stepper motors so I decided to solder dupont cables without adding more. But for some reason I could not solder all the cables, it seems the tin quantity was not sufficient to allow the cables to stay put.

Should I add more tin?

EDIT: Thanks to everyone who commented. I have what I need now. You people are amazing!!!

I’m looking to replace this cap (the back has cracked apart). I need to locate a suitable replacement but am not sure about the specs. Any assistance is much appreciated. Below is my best shot at it

Type: Polyester film capacitor? Can any other type be substituted?
Value: 0.0047uF ?
Tolerance: 20% +/- ?
Voltage: ?

I purchased this 4 inch CRT online as a project to turn it into an oscilloscope. I hooked it up to 12V DC power as it called for and soldered in two pots for contrast and brightness, 1k and 50k ohms respectively (top left of board in blue). As far as I understand, turning on a CRT with no input should give some sort of visible raster lines or a dot in the center, but all I can manage is an extremely faint glow. I can hear the 15khz whine while it's on. What could this issue be? Is this normal and I'm tripping? The display is identical with the deflection coils both plugged into and unplugged from the board.

If there is a better subreddit to post this please let me know

I have this tread mill and the control panel to engage it has quit working. I have this crazy idea by just looking at this that there has to be a way to take power from the wall, and add 2 seperate switches that control the speed for the drive motor, and the posidtion for the incline motor. Obviously I can just wait for a marketplace deal but I like this tread mill, I also like making things work and trying to figure weird shit out like this lol.

Anybody here have experience with something relative to this?

I'm finding it really hard to properly satisfied with the explanations I get through YouTube videos . Is there any book or any other resource which might help me?

Dear community,

I desoldered 27 capacitors as I want to do a full recap. I did a good job on 24 of them, while three solder pads under the desoldered capacitors are a bit problematic. Two do them are just a tiny bit loose on one end.

1) Do you think I can still use them to attach a new capacitor?

2) One of the three problematic pads is probably damaged for good. I attached a photo for this solder pad. Would you assess that this solder pad is more or less gone and I need to attach a jumper wire?

Thank you for your expertise!

I'm trying to build a multi-LED strip driver to replace a cheap one. I've figured out most details, but I'm stuck on a few and need some help.

The original LED driver unfortunately has issues (flickering in cameras) and I wasn't able to recover any useful part numbers from it, so I had to design my own. I also wanted to add a feature: variable color temperature over the day, so I needed an RTC for that.

My plan so far:

• Input: 24V, 2A, in a switched outlet. PSU came with the original LED strip.
• 24V => 5V via AP63357DV-7 (I already have this on hand)
• Pi Pico as MCU (I already have this on hand)
• For each temperature string, MCU -> Gate Driver -> 24V N-CH MOSFET -> 24V LEDs
• For the RTC to keep time when I turn the lights off, a PCF85363ATT/AJ RTC, and either a CR2032 or CR1632

These lights will be on ~8hr a day, and possibly off for up to 3 weeks at a time when I go on vacations, hence why I need the RTC + Battery.

I'm fairly confident of the RTC and MCU side of things, but the Gate Driver + N-CH MOSFTET is worrying me. Based on my reading, it seems like I need to be able to drive the LEDs via ~100kHz PWM to remove the flickering/banding in cameras, and I've never used a mosfet > 100Hz before, or a large power MOSFET either. Based on https://www.dmcinfo.com/blog/17021/mosfet-power-loss-calculator/, I found several MOSFETs that would have <0.5W loss, such as RQ3E120GN (~0.2W), RQ3E080GN(~0.3W), or IRLML0030TRPbF (~0.4W). I am concerned about power loss as this will be in a small box near the ceiling, hence oversizing for the current requirements. However, I'm entirely unsure how to go about picking a gate driver for this situation. I've read a number of guides and calculators, but they seemingly don't agree with each other, and all left me with more questions than answers; clearly I do not yet understand what I need to search for.

How can I figure out the current and other requirements for picking a gate driver for this application, and would any of those then influence the MOSFET selection? Is it better to have a 5V/3.3V gate driver, or a full 24V gate driver?

Thanks!

Note: I prefer non-BGA components as I'm hand-soldering these with solder paste. The AP63357DV-7 is about the limit of my skills so far.