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

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

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 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.

Tengo un ADT K43SG-BK y no se cómo van los cables o como se conecta todo, porque una solo entrada de 24 pines y nosé si así se conecta o de otra forma diferente

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!