Incredible Chinese USB Car Power Supply

Recently I bought a couple of those super ultra cheap cigarette plug extensions to distribute 12V in the lab for various things. As usual with everything chinese, I decided to open it up to see how horrible it was inside, but I also did that to upgrade the wiring since I would be pulling a couple of amps from this and I want to minimize the voltage drop.

This is the incredible thing I found inside the thing as the 5V supply for the USB socket. A 7805 regulator and a 20 ohm 1/4W resistor in series with the 5V output. I guess it could have been worse, they could have used a 5.2V zener or the worst of all just a resistive voltage divider.

China never ceases to amaze me.

Generic Chinese MP3 Player Teardown

As I’ve described in Unbelievable Prices, I bought a crappy chinese MP3 player to use as a “true” sound source (instead of the function generator I use while early-testing my audio projects) for testing my audio circuits without having to worry about accidentally shorting 12V into my iPod’s headphone jack or something like that while probing around.

Yesterday it arrived and as it was expected, it’s the best of Shenzhen. Horrible plastics and build quality, the buttons are super stiff, and overall a shitty product as it was expected to be, but since I’m only going to use it for testing, I don’t care. Here are some pictures of the “beautiful” thing:

As you can see it’s a typical chinese product. The LiPo battery has no markings, except for a weird XI logo, it doesn’t look like a protected pack and the flimsy wires that connect it to the main board can snap off at any second and short the thing out.

Board View

Right next to what looks like the main processor, which sadly I couldn’t find any information about it, there’s a very nicely heat-shrunk clock crystal. On the center of the board you can see a generic 4871 audio power amplifier, and on the left side there’s a BK1080 FM receiver IC.

On the other side of the board all you can see is the horrible LCD and the shittiest buttons you can buy in the Shenzhen market.