EEVblog #321 - Google Nexus 7 Tablet Teardown

[Kashif]

Hi Dave,

Is audio coming from the processor through a external amp or does speakers have some dedicated codec chip?

Thanks,
Kashif

[T4P]

Always a dedicated QFN/UFBGA codec+Class D chip, never straight.
How the hell do you put out a digital signal straight i don't know!

[TbayBoy]

I will guess the cutout with nothing in it in the top is for the rear facing camera in the REV2 version.

My guess also

[LaurenceW]

Hmm - not sure I buy the "copper = heat-sink" argument. Consider this.

It's a single cell lithium battery, so that's about 3.7V. The mAH rating was something like 4300, so that gives the cell a total energy storage of around 16 WHr. Now, if the device is slated to run for around 8 (or more) hours, it can only be drawing that energy at a rate - power - of 2 (or less) watts.

That's the WHOLE device - processor, screen, backlight, memory, Wifi, audio, other devices, etc. It's hardly going to break out into a sweat at these power levels, is it?

With a plastic back and tough EMI regulations, that copper is there to stop the tablet from interfering with grandma's AM radio.

[saturation]

I got one of these as my first tablet, mostly to read pdfs.  Its decent enough for older eyes, but its still easier on a bigger screen, like the iPad, which I do not own or will not buy because it doesn't give me control of the software or hardware like Android does.

A great job with the tear down.  Even with competitors doing similar tasks, eevblog's version has a unique flavor as you dig into the component level, while most stay at the board level.

Here are some of the best:

http://www.informationweek.com/byte/news/galleries/personal-tech/tablets/240003315

http://www.isuppli.com/Teardowns/News/pages/Low-End-Google-Nexus-7-Carries-$157-BOM-Teardown-Reveals.aspx

Some insights from all the non-eevblog teardowns:

The BOM suggest the Nexus 7 is a loss leader, it costs more to make than its being sold.

Given how fast things are going in the tablet market,  Nexus 7 is essentially disposable. It will probably be obsolete in 1-2 years, way before the LiPo battery gives out.  Nevertheless, its so easy to work with and modular that when used Nexus 7s hit eBay in a few years, it should be easy to repair with cannibalized parts, it would be worth it if a fresh battery is still around and economical to buy.

The PSU has a load sensor, as drops charge rate if you use certain microUSB cables.  Cables dedicated to charging, such as the OEM Motorola Droid cables are no problem, but some 3rd party cables I have reduce the current flow.

Wifi supports n protocol, but no 5 GHz radio.

Complaints on-line for US users with production hardware defects, estimating Amazon complaints its about 10-20%, rated 4/5 stars.  The defects seem batch related, Amazon and Google Store has gotten a fair share, as Staples.com related sales have ne'er a complaint, and their market is not tech savvy either, rated 4.75 stars.  Amazon and Staples have about a similar number of reviews, ~ 90. 

The defects are:

battery = dies spontaneously, fail to charge after 1 week of use, and shows itself as erratic operation and unexplained shut downs with a full charge

glass panel separation = unit operates but causes clicking sound
glass is not Gorilla glass, just 'Corning' glass.  Some folks have shattered their screens when dropped yet online reviews show it resists cracking when dropped [ full youtube videos of iPads vs Nexus 7 being dropped from 3 feet] but will crack if the glass separates from the LCD. 

capacitive sensor attachment = loosens, leading to dead spots on the screen, squeezing the screen can correct the issue

mic failure = fails to receive input after some time

Android OS is is 4.1.1 released 7/12 and is glitch free, so far.  Install was as smooth as Dave showed it and effortless. Apps seem to be bug free.

In toto, don't throw away the box for at least 12 months, to avail of the warranty.  If you do buy one, buy it retail so its easier to return because the prices are actually much higher online, than retail!

[T4P]

So your same "not gorilla" analogy speaks for Samsung's Crap SIII not being Gorilla II?

[saturation]

I don't really know T4P, Corning has a site listing all Gorilla glass products, and most phones and pads I know using it rarely are reported broken.  On some Nexus 7, the screen breaks somewhat easily.  Nexus 7 is not listed on the Gorilla site, and confirms what other reviews suggest.

http://www.corninggorillaglass.com/



OTAH, there is this test:

So your same "not gorilla" analogy speaks for Samsung's Crap SIII not being Gorilla II?