KEY FINDINGS:
• If you’re looking forward to swapping out bands, there’s not much to it. A button on the back case releases a springloaded metal peg in the band, allowing it to slide right out. There are no external screws, however, so we reattach the band for leverage and use a knife to get inside the belly.
• Disconnecting the display isn’t easy, as the display cables are trapped under a springy bracket. A quick flick dispatches the light adhesive securing the 3.8V, 0.78Wh lithium-ion battery. Apple claims the 205mAh battery should provide up to 18 hours of use. It seems small in comparison to the 300mAh batteries found in the Moto 360 and Samsung Gear Live.
• We encounter the tiniest tri-wing screws we’ve ever seen, before getting to the speaker, which comes equipped with an O-ring for water resistance. Behind a very small panel we find a set of contacts that align perfectly with the location of the hidden diagnostic port. We remove the Digital Crown bracket, the final obstacle keeping us from the S1 SiP.
• The back of the S1 isn’t pretty—with ribbon cables running to every peripheral and gobs of adhesive gripping it in place. Pulling this mess out is destructive. It’s a solid block of plasticky resin, hiding treasures deep within, such as the STMicroelectronics C451 gyroscope and accelerometer.
• Back to the display panel, we find a lonesome chip: Analog Devices AD7166 ARM Cortex M3-based Touchscreen Controller. At the bottom is the pulse-pounding sensor action. And lenses. Apple’s heart rate monitor is actually a plethysmograph—it looks and acts like a pulse oximeter.
• Repairability Score: 5 out of 10 (10 is easiest to repair). The band is easily removed and swapped. Removing the screen is difficult, but not impossible. Once inside, the battery is quite easy to remove—only mild adhesive holds it in place. While not proprietary, incredibly tiny tri-wing screws are a repair hinderance. Removing any other component is essentially impossible—all peripheral cables are soldered onto the back of the S1. The fully encased S1 system makes board-level repairs impossible.