Set-top box teardown: Android isn’t just for smartphones

Article By : Brian Dipert

Google (and parent company Alphabet) is known for the Android operating system, among other things (an obscure search engine, for example). It leverages Android as the software foundation of numerous hardware product categories; smartphones and tablets are perhaps best known, but also included are things like smart watches, automobile audio head units, and set-top boxes (STBs), the dissection showcase in this particular teardown.

To be clear, I’m not talking about Chromecast devices, the first generation of which I tore down a few years ago. While these particular products can play back an online stream, it needs to be initiated elsewhere. An STB, conversely, handles all of the service(s) interaction by itself (although in this particular case, it encompasses a superset of Chromecast functionality); Roku’s devices are perhaps the best known in this product segment.

Google and its partners make STBs, too, although you’d certainly be forgiven if you didn’t know that. Until recently, with the well-regarded Chromecast with Google TV (which I also mentioned just recently), they haven’t exactly taken the market by storm. NVIDIA’s Shield is probably the most popular Android-based STB to date, arguably primarily because it’s also a decent gaming platform. Today’s “victim,” the Asus-developed and co-branded Nexus Player, was the first Google-branded STB to enter the market (the Nexus Q precursor wisely never made it to retail).

This particular unit came into my possession by virtue of a longstanding aspiration to migrate away from a Windows Media Center-based TV reception and distribution scheme to one based on SiliconDust’s HDHomeRun PVR, with Nexus Players handling the per-TV playback duties. Nearly six years after supposedly saying “farewell” to Microsoft, however, I’m still relying on a set of geriatric Xbox 360s along with an equally-obsolete copy of Windows 7 running on a mini PC. And since the Nexus Player is no longer supported by Google either, it’s time to take it apart and see what’s inside.

I’ll as-usual begin with a series of unboxing shots:

Take off the top, and voila (for scale, note that the Nexus Player is 120 mm, i.e., 4.7 inches in diameter):

Let’s put the Nexus Player aside for the moment, and see what else is inside. First off, there’s a diminutive bit of quick-start documentation:

Underneath that is the remote control (speaking of gaming, Asus also offered a separate gamepad accessory for the Nexus Player) as usual alongside a 0.75″ (19.1 mm) diameter U.S. penny for size comparison:

Diving further into the box, all that’s seemingly left is the warranty documentation:

But wait! Where’s the AC adapter? And speaking of power sources, was Google really too skimpy to toss in a set of batteries for the remote control? Go back one level of cardboard, turn it upside down, and aha, there they are!

Here they are again, this time freed from their cardboard captivity, revealing the AC adapter’s barrel plug (versus the more conventional mini or micro USB connector):

Here’s a closeup of the sticker attached to the shrinkwrap on one side of the AC adapter:

And, with the shrinkwrap now removed for clarity, here are the AC adapter specs (revealing, among other things, why a USB connector wasn’t used; that’s a 12V, not 5V output):

Enough teasing with appetizers, let’s cut to the main course, post-shrinkwrap removal. Top side view first:

Here’s the frontside (by the way, finishing out the dimension details, the “hockey puck” is 20 mm, i.e., 0.79 inches high and weighs 235 grams, i.e., 8.3 ounces):

And here’s the backside. What’s inside that chassis cutout will shortly become apparent:

Flip the unit over and here’s what you’ll see. A thumbprint-sized Bluetooth pairing button in the center dominates the landscape, with a diminutive LED above it:

Now for that cutout (with the perspective also giving a nice closeup of the FCC ID, MSQ-TV500I):

Left-to-right (although recall, we’re currently looking at the system upside down, so the order would be reversed in normal orientation/operation) are the DC power input, a micro-USB connector (usable, for example, in supplanting the built-in Wi-Fi networking facilities in favor of wired Ethernet in combination with an adapter, which is how SiliconDust had suggested configuring the unit for the most robust connectivity), and the HDMI output.

Time to dive in. Turns out all I needed to get inside was a thin flathead screwdriver (acting as a spudger):

Let’s quickly deal with the comparatively “boring” upper half first:

The only item of note, unless you’re really into black plastic, is the sheet of copper used to transfer heat away from the circuitry underneath it. Spoiler: this isn’t the only thermally-intended copper (and other metal) you’ll see throughout the system. And why it exists will also shortly be apparent. Now for the more meaningful half of the system “sandwich”:

Items of initial note include a connector (presumably intended for testing and programming on the assembly line) along the left side; the HDMI, micro-USB, and DC power connectors now correctly ordered; hints of antennas at left and top, embedded in the PCB underneath a metal heat sink; and metal pieces on either side of the black plastic cutout. Let’s get those off first:

Now upside-down:

They seem to serve no electrical or other functional purpose, existing solely to bolster the system’s mechanical stability around the cutout. Next, let’s get that heat sink off, complete with a warranty-voiding sticker on top of one of the four Philips screw heads:

The PCB underneath is now fully exposed:

And one more screw removed enables its removal. Topside first:

Those aforementioned embedded PCB antenna are now clearly visible; FCC certification documentation indicates that the one at top does double-duty for Bluetooth and 2.4 GHz Wi-Fi, with the other handling 5 GHz Wi-Fi duties. On the right side is a THGBMJG6C1LBAIL 8 GByte eMMC flash memory from KIOXIA (formerly Toshiba). In the upper right corner is ITE Tech’s IT8566E HDMI transmitter. And I bet you’re wondering what’s under that Faraday cage on the left side, aren’t you? Let’s find out:

The IC topside is, I realize, too shiny to photograph cleanly, so you’ll have to take my word that its markings identify it as Broadcom’s (now Cypress Semiconductor’s) BCM4354, which handles both 2×2 MIMO 802.11ac Wi-Fi and Bluetooth 4.1/LE duties for the system. Then again the proximity of those PCB-embedded antennas were a tipoff, weren’t they?

Now let’s flip the PCB over:

At top is an LED. At bottom, above the micro-USB connector, is the earlier-mentioned Bluetooth pairing switch. And pretty much everything else is obscured by another, much larger, Faraday cage, which, oddly enough, pops off with no more than a touch:

Both sides of the Faraday cage have pink thermal tape; wonder what it’s there for? Wonder no more:

The smaller of the two ICs is an Intel Atom Z3560 1.83 GHz quad-core SoC, also containing (among other things) a G6430 graphics core from Imagination Technologies. An Intel CPU might be a surprise, given the preponderance of Arm-based designs in the Android world, but Android also supports x86; remember Intel’s brief pursuit of smartphones (for which the Z3560 was originally intended, actually)? And reflective of the underlying reason why Intel didn’t succeed in smartphones, there’s that heatsink, along with all that copper, which come to think of it we’ve also seen plenty of in other Atom-based designs recently.

Alongside the SoC is a 1 GByte SDRAM, of unknown specs and supplier. I can’t discern the markings on mine, and the FCC photos aren’t clear, either; this site claims it’s a DDR3-generation device sourced from SK Hynix, but the exact speed bin is still undetermined, and I also wouldn’t be surprised if Asus got this commodity device from multiple sources over the Nexus Player’s lifetime (depending on who had the lowest price at the time).

Returning to the remainder of the system “sandwich,” there’s another heatsink underneath the PCB (surprise!):

And underneath it (more surprise!) another swath of copper. Also visible is the translucent piece of “rubberized” plastic that transmits the LED output to the outside world:

Wrapping up, let’s turn our attention to the remote control, which, as we already know from the product documentation, pairs with the main unit over Bluetooth (versus, for example, infrared). Removing one screw got one end of the two halves of the enclosure starting to come apart, while the aforementioned flat head screwdriver wedged apart the other end:

But the portion in the middle remained stubbornly stuck together until I realized that underneath a “rubber” strip were two more screws, with a test point array in-between them:

Mission accomplished:

One half was (again, unless you’re into black plastic) pretty boring once the PCB was lifted away:

The PCB itself is much more interesting, with a Broadcom (again, now Cypress) BCM20734 Bluetooth(-only) transceiver dominating the landscape on one side:

The other (top) half is nothing but buttons, along with a rubberized button-to-switch intermediary layer:

And with that, nearly 1,700 words in, I’m wrapping up! Over to you for your thoughts in the comments!

This article was originally published on EDN.

—Brian Dipert is Editor-in-Chief of the Embedded Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.

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