To find spare parts like the charging logic board, charging port, and USB plug PCB dock connector for your Samsung Galaxy A20 (SM-A205), you can try the following options:

1. Official Samsung Service Center: Contact an official Samsung service center or authorized repair center. They may have genuine spare parts for your device.
2. Online Retailers: Many online retailers, such as Amazon, eBay, or specialized mobile phone repair parts stores, offer a wide range of spare parts for smartphones. You can search for the specific parts you need on these platforms.
3. Local Electronics Repair Shops: Visit local electronics repair shops or mobile phone repair shops. They might have the spare parts you require or can order them for you.
4. Samsung's Website: Check Samsung's official website or support page for information on how to purchase genuine spare parts for your device. They may have an online store for spare parts.

When you find the parts you need, you can order them and have them installed by a professional if you're not comfortable doing it yourself. It's important to ensure you're getting genuine parts to maintain the quality and functionality of your Samsung Galaxy A20.