The schematic for an (designed for the FT-100/FT-817/FT-857 series with an 8-pin round plug) is different from the MD-100C (designed for Icoms with a modular plug). Ensure you are searching for the exact suffix.
I should also check if they're aware that the MD-100 isn't a real product. Maybe they confused it with another device, like the Yaesu MD-380 or similar. Clarifying that could help them find the correct information. Additionally, emphasizing safety protocols is important if they're working on hands-on projects to prevent accidents. Yaesu Md 100 Schematic
Offers two stages of low-frequency attenuation. The schematic for an (designed for the FT-100/FT-817/FT-857