Fried Beaglebone Cape ? Broken Homeplugadaptor?


#1

Hi there,

after building most of the bits together it was time for my first real bootup and test. I noticed that I couldn’t get an IP connection to the OpenROV through the top-side tether, the static IP setup and using Chrome to access the UI. After some testing and debugging I noticed that the middle diode of the top-side tether homeplug adaptor usb board wasn’t lit up (the one that seems to indicate that the 2 homeplug boards know about each other).

Some fiddling around with the Electronic Components (due to go in the acryllic tube) showed that I could get the lights to flicker every now and then but not in a repeatable matter. I did create some arching in the process (had the plus / minus Molex pins coming from the batteries touching…)

Now the situation is as following:

  • No diodes working on the Homeplugadaptor on the chassis (2 diodes working on top-side)
  • Beaglebone cape is giving me 5V on the 5V marked plus connector, but is giving me 0V on the 3.3V marked plus connector

So my questions ? How can I check if the cape is in good working order ? It seems strange that the 5V pin works, but the 3.3v doesn’t (used all possible combination with ground pin)

If I’ve fried my homeplug adaptor - where in Europe can I get one ?

Other ideas ?

Best,

Peter


#2

Hi Peter:

It may be that it's your BeagleBone that is not working.

The cape has a switching converter to regulate the battery voltage down to 5V, and then that is pushed down to the BeagleBone which has an on-board 3.3V regulator. That 3.3V is sent back to the Cape and then to the HomePlug adapter. Does the BB start to boot when you apply power to the Cape?

You might want to try powering up your homeplug adapter with a couple of alkaline batteries in series (~3.1V), and see if that works. Your adapter may not be broken at all.

When you pull apart your BB/Cape combination to do some debugging, do a very careful inspection of everything to see if there are any fried traces or blown chips, before investing money in a new BeagleBone.

Hope this helps.

-W


#3

Hi Walt - thanks for the input - I tried that (got 3.1 V out of the 2 batteries) but the lights on the Adapter soldered to the Cape are not coming on anymore, so my assumption that I fried the homeplug adaptor seems true.

Just to be clear - if the Cape doesn't provide any power on the 3.3 V pin (It does on the 5V pin) then I can be relatively sure that either I fried it or it was already broken somehow ?

There's no special switch / solder thing or anything else i have to do to turn the 3.3 V pin on ?

Best,

Peter