iFixit's teardown of the iPhone Duo shows potential causes for cracked screens

The Duo is the most repairable folding phone yet, but opening it up isn't for the faint of heart.

iFixit

iFixit's latest teardown of the iPhone Duo has arrived, and it's especially interesting because of the device's complex folding display. The DIY repair group spotted some interesting details about the hinge design that may explain screen cracks some buyers are seeing. It also said that the Duo is the most repairable folding device yet, but opening it up wouldn't be for the faint of heart. 

To make the screen fold smoothly while minimizing the appearance of a crease, Apple took a twofold approach (sorry). The first part involved creating a smooth curve for the screen inside the hinge by using multiple curved guides that extend when the display is folded and retract when it's open. A center support bar running along the hinge also drops to accommodate the fold. 

Secondly, Apple hid the crease by using oval pixels aligned a specific way and effectively "blurring" the fold point with a nano-texture coating. iFixit showed this effect precisely by putting the screen under a powerful microscope. 

The retractable curved guides and support bar may point to the potential cause for screen cracks. To figure this out, iFixit built a 3D hinge model from "teardown footage, patents and CT scans, then compared it with the reported damage locations." In one of its simulations, it found that the center bar failed to drop far enough, creating a stress point when the screens fold comes down on it. 

The company also found that, despite the iPhone Duo's IP68 dust resistance rating, fine particles can make their way into the hinge mechanism (just like they can on other folding phones). That can cause the hinge to "crunch" and damage the screen, causing the "green line" damage pattern across the display seen by some users. The reason, says iFixit, is that while the internal mechanism is dust resistant, the hinge mechanism apparently is not — so you may want to avoid taking your Duo to the beach. 

Other parts of the Duo are more solid and easily repairable. iFixit was able to remove the outer screen and batteries, and said that the smaller components were "fairly accessible." The inner display and hinge accounted for the largest deduction and iFixit noted that "many are opting for AppleCare+ coverage for this reason... the early reports of screen failures make clear that display replacement is more than a distant possibility." With all that, iFixit gave the iPhone Duo a provisional 5/10 repair score, pending availability of replacement parts.