Hackaday Links: February 16, 2014

hackaday-links-chain

[Moogle] wrote in to see if anyone can figure out why his unused electrolytic capacitors are popping. This is the behavior you see in populated caps whose electrolyte dries out. But these are still in his parts bin. Anyone know why they would pop when going unused?

We see a lot of BIOS flashing hacks; but it’s always a handy thing to know about when you get in a bind. Here [Adan] shows us how to reflash a corrupt BIOS using a Tiva C Launchpad board.

Wanting to hack together her own blow gun [Carlyn] scrapped a handheld vacuum cleaner. When she discovered the pump could not easily be converted from suck to blow she made a handheld suction manipulator which picks up paper plates and a few slightly heavier objects.

Unfortunately a drill press is not one of the tools we have in our lair right now. If we did, this tip about using it to help tap threads in a hole would come in really hand.

Retro computing fans will appreciate this Z80 computer build (translated). It’s a fairly large mainboard with plenty of chips, resistors, buttons, and seven segment displays. Excellent. [Thanks Daniel]

We start to drool a little bit when we see a teardown post that shows off a piece of equipment really well. We’ve already reached for a bib to catch the slobber from pawing our way through [David's] teardown of an HP 6010A bench supply.

Comments

  1. mjrippe says:

    “Anyone know why they would pop when going unused?” Because he is using cheap off-brand capacitors? It is amazing they would fail so easily, but that’s why I buy brand name caps from reliable sources.

  2. VintagePC says:

    Re: Caps

    There’s a reason they’re cheap and plentiful… and also a reason supply houses like Digi-Key don’t stock those cheap brands.

    Even then… you can get a well stocked parts drawer with 100 good quality panasonics for ~$10…is it really worth problems like this and dubious quality to save a few dollars via fleabay?

  3. Figureitout says:

    Regarding the capacitors, that sucks. I had some crappy power supply boards from china, they weren’t even soldered correctly and a cap. nearly blew in my dad’s face; this was w/ power though…

    BIOS link was pretty cool, and z80 computer (going to build one of those too).

  4. Danjovic says:

    Hi Mike. The credits of the Z80 kit should go to Victor and Fabio.
    Regards,
    Daniel

  5. ejonesss says:

    if i had to guess why capacitors would pop without power or heat it is probably

    1. barometric pressure changes if you have some severe weather changes say a hurricane that can get down to 900 to 800 milibars the external reduced pressure means higher pressure in the capacitor.

    2. due to the race to be the winner in the green and rosh movement capacitor makers are using biological material to make the electrolyte .

    if you have a half of a container of milk (best in plastic bottle (some fruit juices )) will build up gas pressure as they decompose and the container will bulge.

    my guess is some biological or food based.

    • Leithoa says:

      * green and rohs

    • F says:

      Why bother blaming it on greed, when you can blame it on people who want clean water? Yes indeed, the world will be a much better place if capacitor makers were allowed to dump their waste in the river. Why let’s ask the people in New York State, how they like the electronic waste in the Hudson.

      • justice099 says:

        You know how we could be REALLY green? Let’s go back to the stone age!

        • Whatnot says:

          Case studies have shown you can be perfectly fine using environmentally sound materials, and the laws are made by people with an interest in their economies and in my experience the guidelines are never made until a usable alternative is available, and before that time they just stay quiet and ignore the pollution.

          And the capacitors getting worse (including japanese ones) has started before they made the ‘green’ rules. So I would guess it’s indeed economical, and/or incompetence.

  6. Jim Coleman says:

    In response to the hole tapping link:
    I feel that anyone with a live or dead center on hand should probably be familiar with this process. For those who have a drill press and no center, you can mount the tap directly in the chuck to hold it straight. It should be easy enough to turn the spindle by hand for most taps of a size hobbyists will be using. If you do need a little extra leverage, the chuck key inserted into one of the holes works well. It should also be noted that the workpiece should be secured to the table to keep it from moving between drilling and tapping, especially when using the center approach described in the link.

    It should be noted that none of the tapping process is done with power applied by the spindle’s motor, all force will be applied by hand. Happy tapping!

  7. F says:

    That drill press technique has been around for decades, I think it’s mentioned in the old Ford mechanic’s shop manual. Hang a weight on the drill press feed handle and you’ll have both hands available.

    You really want to use both hands on the tap wrench. I disagree with what he says about using any wrench. I’ve tried this with other wrenches, it doesn’t work so well because you are exerting side forces on the tap, if you are only wrenching from one side. You will get much better results if you use a tap wrench and both hands.

    I would also be more conservative about backing out and chip removal. Busted taps are no fun at all and I have busted them with that technique. Back out often and keep those chips from accumulating.

    I would make sure the drill press is unplugged and I would also put the failsafe key in my pocket during this procedure. Don’t forget safety glasses, chips can fly!

    And don’t forget the most important step of deburring afterwards, otherwise you can cut yourself on the sharp edges.

  8. Mike Lu says:

    A space heater or other heating appliance makes a great test load for testing big 100V or so PSUs. Those without motors or thermostats will run happily on DC. Hair dryers also work just fine on DC.

  9. mauswerkz says:

    For the tapping trick, I’ve got another one:

    Instead of using a dead/live center (something those of us without lathes won’t have laying around), try this:

    Get an automatic center punch
    Disassemble it and disable the mechanism that makes it go “snap”
    Reassemble it so that the center bit is now spring loaded.
    Chuck that in your drill instead of the dead center
    Use as described in the link, except this is spring loaded which can be helpful.

    • 0xfred says:

      Thanks for the tip. I was going to make a spring loaded centre for taping on my lathe, but modifying a centre punch instead is a great idea. (I might make one on the lathe anyway just because I’m enjoying using my new toy.)

  10. Tyler says:

    Interesting to see the 6010A, as I have a 6012B 1kW supply that is instead 0-60V, 0-50A (explains the aluminum output rails, doesn’t it?)

    Lack of a power supply connector is for obvious reasons if he looked at what the input current is on those suckers at 120V (I run mine on 240 split, seems happier). Fantastic — if a bit peculiar — power supplies. Frightful hack instead of getting the right TO-3 transistors.

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