The MIJING C21 Testing Tools Middleboard is a professional-grade 4‑in‑1 diagnostic fixture specifically engineered for the iPhone 13 series, including the 13, 13 Mini, 13 Pro, and 13 Pro Max . This motherboard function test fixture is designed for testing middle‑layer mainboards after layer separation, allowing technicians to quickly detect logic board faults without complex jumper wires or guesswork.

The tool is an evolution of the concept introduced with the iPhone X—where Apple adopted a two‑piece PCB sandwich design to save space and increase battery capacity—and is now essential for professional repair shops offering board‑level services . Using the C21, you can connect the upper and lower motherboards for testing and repair, avoiding problems after installation and dramatically increasing maintenance speed .

Key Features (Standard C21)

• 4‑in‑1 Full Series Support – Compatible with iPhone 13, 13 Mini, 13 Pro, and 13 Pro Max in a single fixture, eliminating the need for multiple patchwork solutions .
• Simple, Solder‑Free Operation – Test the motherboard before re‑laminating the two PCB layers; prevents repeated disassembly and reduces the risk of breaking delicate boards .
• Two Testing Methods – Method 1: Connect the screen cable, power cord, or battery to test basic functionality. Method 2: Connect the end plug to implement the brush/flash function without removing the board .
• Easy Installation – Place the lower main board into the fixture, put on the pinboard, place the top board, and cover the test rack. Quick setup with minimal hassle .
• Compact & Portable – Small footprint (approx. 100×91×21mm for the Pro version) keeps your workspace organized and makes the tool easy to carry .