XZZ Motherboard Layered Test Fixture for iPhone 12 Series

From the iPhone X onward, the logic board is a sandwich: two boards stacked and soldered together through an interposer. When one of them is faulty, a layered test fixture lets you run each layer on its own instead of guessing which one to rework.

The FIX-12 is a layered test fixture from XZZ (Xinzhizao) for the iPhone 12, 12 mini, 12 Pro and 12 Pro Max. It's made from flame-retardant, corrosion-resistant material and uses customized gold-plated spring probes for contact with low reading deviation.

When the FIX-12 is needed

• A separated board that fails to boot and you need to find the faulty layer.

• Testing a top or bottom board before reballing it to its partner.

• Confirming a repair before you solder the sandwich back together.

• Swapping a damaged layer between donor boards.

Using the fixture

Clean the interposer pads before seating a board, since flux and solder balls stop the spring probes from making contact. Seat the layers gently and evenly, then power up through your usual boot cable.

The fixture measures 106 × 95 × 16 mm and weighs about 181 g. Store it covered so the probes stay clean and straight between jobs.