iPhone X-12 Double-stacked Board Separation & Recombination | REWA Academy Tips

Introduces methods to address the issue of layers failing to fit closely during double-stacked motherboard repair, leading to large gaps and pseudo soldering.

Recommends using a professional motherboard heating platform instead of a hot air gun for beginners, to prevent uneven heating and deformation.

The optimal heating temperature is 155°C-165°C, as the layers are joined with low-temperature solder paste.

Existing tin on the bonding pads must be completely removed, as any residual tin will adversely affect subsequent soldering.

It is important for solder paste to maintain proper humidity during reballing; if too dry, it will adhere to the stencil upon removal and result in unevenness.

During recombination, when solder flux spills and the logic board sinks, gently nudge the logic board with tweezers to ensure the two layers fit closely.

If the motherboard is deformed, it can be corrected using a flat board and rubber bands, placing soft paper underneath to avoid crushing components.

Also introduces a simplified recombination method when the middle bonding pad is not damaged: keeping original tin on the bonding pad and only removing thermal grease.

A 0.05mm thick metal pad surrounds the signal board, designed to maintain a 0.05mm gap between it and the logic board, preventing solder ball bridging.

REWA Academy offers complete course packages to improve motherboard diagnosis and repair capabilities.