One man’s trash…

I was wandering around the Hua Qian Bei district yesterday with xobs trying to buy a couple of power supplies for bringup of an open-source quad-core ARM laptop we’re building, and lo and behold, I came across this:

It’s the first time I’ve ever come across one of my former products in the Shenzhen markets. It’s kind of neat because I have intimate knowledge of how it might have ended up at this reseller’s stall. It also brought back old memories of agonizing over the logo color and placement — I think we tested over a half-dozen shades of gray before we settled on this one, and we had to fight with the printer to get the eyes just right and no smearing despite printing on a curved surface (accessories are in many ways harder than the product itself). Amusingly, this lady is selling the power supply for less than it cost us to originally buy it (you can just see the top of her head in the photo, she ducked behind the counter to find the power supplies we were buying, and I snapped the photo while she wasn’t looking).

Most of the excess inventory for this power supply ended up in the US office to handle exchanges & returns, so I’m pretty sure these are from a batch of power supplies that we had rejected. If I recall correctly, I had discovered an issue where one of the inductors in the power supply was missing the glob of glue required to hold it in place. Shipping the unit subjected the power supply to vibration, which caused the inductor to rub against a neighboring part. The rubbing could wear off the enamel on the inductor, which ultimately leads to the inductor shorting against the neighboring part. The power supply’s internal fuse correctly blows when this happens, so it wasn’t a safety issue; but the defectivity rate was around a few percent after shipping. I think a few thousand power supplies were sent back to the manufacturer over that issue. My guess is that after many years, the manufacturer finally found a sucker^H^H^H^H^H^H reseller who would peddle it in the markets.

Inspires confidence in the other ‘brand-name’ power supplies she was peddling, doesn’t it? On the other hand, I did buy a Lenovo-branded power supply that was perfect for my needs. ‘Brand new’ with plastic over the logos, it set me back only $4 a piece, and I did verify on the spot using a multimeter that the power supply did output the correct voltage. Probably good enough for development use, and at that price you just buy two in case one breaks.

18 Responses to “One man’s trash…”

  1. Theon144 says:

    Open-source quad-core ARM laptop? Where can I learn something more about that?

    • bunnie says:

      Just stay tuned here. I’ll be posting more about it as the prototype comes along!

      • Taniwha says:

        Heh – I’ll buy one – I had the bright idea of building a tablet – with slots – out of the new Altera parts with the dual core embedded ARMs – but leaving the bulk of the gates free to be allocated to the ‘slots’ which usually would probably be little more than connectors – it seems to me that we OS hardware hackers are running out of platforms we can plug our stuff in to – time to make our own

        (the hard part of doing this is graphics acceleration, haven’t found a good solution to that problem yet)

      • Taniwha says:

        Oh du-oh, of course, you have to wait for freescale’s announcement on Tuesday, I’ve been completely unable to get data sheets out of them (I’m not building a laptop or tablet)

      • raywin says:

        I’ll preorder one based on the Chumby experience alone.

        There is a real absence of quality “open” electronics, thank you guys for trying to change that!

  2. Aris says:

    Have you seen the Cubieboard development out of China?

  3. With the connector you used on the PSU, i would gladly have bought even a faulty wall wart. Getting the voltage right is not a problem. Getting it fed into the Chumby is.

    I’ve got two Chumbies (Chumba and Wamba). One of them is in permanent state of open brain surgery since i haven’t managed to get a non destructive power source operation drawn to it…

    But let this be my late tip-of-the-hat for all you did to get those cute boxes to my home!


  4. Russ says:

    After about a year, my chumby wallwart failed, wonder if it’s related…Mine is a Shenzhen Frecom FM050020-C. It still produces 5V, but under load, drops to around 2.5V.

  5. mary says:

    OMG. Hilarious.

  6. Hardcore says:

    I spends a lot of time in this area and working with various China factories.

    You don’t EVER want to buy this sort of PSU from these people.
    Many are a serious fire hazard.


  7. James Chan says:

    As they say, “blast from the past”!

  8. You’re so cool! I dont suppose Ive learn anything like this before. So nice to seek out any person with some original ideas on this subject. realy thank you for starting this up. this web site is something that’s wanted on the net, someone with just a little originality. helpful job for bringing one thing new to the web!Useful info!

  9. mianchen says:

    Bunnie, the pinyin for 华强北 is Hua Qiang Bei, not Hua Qian Bei…

  10. It’s hard to find educated people in this particular subject, but you seem like you know what you’re talking about!