Faulty Power supply?
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Faulty Power supply?

by chaddlesmcgee on Fri Nov 23, 2012 7:58 am

Hey guys,

It really sucks that my first post on theese forums has to be this one.I was hoping to present some funky lawn mowing shake making poetry creating fantastic gymnastic robotic contraption made out of Rasberry Pis and a few cable ties but alas I have hit a bit of a snag.

I recieved my Rasberry Pi starter kit in the mail Yesterday. Very nice kit. messed around with it for a few hours, getting to know the operating system etc. Got home from work today and plugged it in and started installing some new packages etc. It then just turned off. I went to unplug it and the case was VERY VERY hot. Plugged it back in and it wouldn't boot up. Just had the red power LED glowing.The board started getting quite warm after I plugged it in so I unplugged it and decided to have a look at the adaptor. Got out the multimeter and did a few quick checks and was shocked to find that the power adaptor was reading 9.43V! It was also making a high pitched noise that it was not making when I first turned it on.
Put that aside and powered up the benchtop switchmode lab supply (set at 5.2v with a cut out at 1.2amps) andpowered up the pi.Same deal. Red light on but not booting up. Pulled out the SD card and reflashed it on the off chance something had become corrupt. Still no joy.
My guess is that the adaptor is faulty and has done some damage to the mainboard.Although I am hoping it is something fixable. I am really keen to get back and actually start interfacing some hardware with my Pi but it's not looking good. :( Do you guys have any suggestions? Any simple test or procedure I may have overlooked? Or am I going to need to return my adaptor and pi?

Regards,
Chad
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Re: Faulty Power supply?

by adafruit on Fri Nov 23, 2012 11:53 am

that's very odd to hear, how were you testing the power supply?
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Re: Faulty Power supply?

by chaddlesmcgee on Fri Nov 23, 2012 8:55 pm

Hey there,

Good news and bad news.
I did some more troubleshooting and realised that I had overlooked a potential point of failure: The microSD to SD adaptor. I swapped it out with another I had lying around and it worked! Booted up nicely. I am very relieved. Having said that it still means that I have a faulty power adaptor and a now fried MicroSD to SD card adaptor however I am not too fussed about the latter. I am, for the moment at least, using a switchmode desktop supply. It is bulky but gives me fine grained control over the output.

In response to your question, I tested the power adaptor with a multimeter across the + and - of the USB output.I used an old USB through adaptor with a piggy-backed barrel plug to make it easier to take the following photos.

Image
http://flic.kr/p/dvCB8r

Image
http://flic.kr/p/dvCBfR

I would be quite happy to post the faulty adaptor to you should you wish to investigate it further.

Regards,
Chad
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Re: Faulty Power supply?

by adafruit on Sun Nov 25, 2012 1:23 pm

Thanks, we'll give this feedback to the power supply factory - what readings do you get from a regular USB port?
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