Mnemonicman
Posts: 3
Joined: Tue Aug 21, 2012 6:12 pm

RPi will not power on

Tue Aug 21, 2012 6:22 pm

Today as I was about to power on the RPi I heard a muffled poof in the direction of the AC usb power adapter. Now the lights on the RPi are off and a faint burnt smell coming from the AC adapter. I tried a different power adapter and nothing works. No burn marks on the RPi that I can see or any burnt smell.

Is this thing dead? Or what can I test to verify that it is toast? It's only a $35 device but it was someting interesting to fiddle with.

Oh yes and I also tested the voltage on the RPi and it now shows 1.19V. I was going to order another one anyways but not this soon.

drgeoff
Posts: 11552
Joined: Wed Jan 25, 2012 6:39 pm

Re: RPi will not power on

Tue Aug 21, 2012 6:45 pm

If the poof came before you plugged power into the RPi then something was wrong with the adaptor.

If the poof came as you plugged the powered up adaptor into the RPi then either of them could have had a fault and possibly damaged the other.

If the RPi isn't working with another good PSU then the RPi has a problem. But are you sure the second supply is up to the job? Where have you measured 1.19 volts?
Last edited by drgeoff on Tue Aug 21, 2012 6:47 pm, edited 2 times in total.
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lavers
Posts: 17
Joined: Mon Jul 09, 2012 3:45 pm
Location: Canada

Re: RPi will not power on

Tue Aug 21, 2012 6:45 pm

Give it a few hours and then try again. The Pi has fuses that, when blown, take a while to restore themselves. It might just be that you gave it a power surge and blew the fuse.

Mnemonicman
Posts: 3
Joined: Tue Aug 21, 2012 6:12 pm

Re: RPi will not power on

Tue Aug 21, 2012 7:35 pm

drgeoff - It was as I plugged in the AC adapter. I immediately unplugged the AC adapter afterwards. I checked the wiki for how to check the voltage going to the pi. http://elinux.org/RPi_Hardware#Power
The points TP1 and TP2 can be used to test voltage.

lavers - I hope you're right. It's a fun device to tinker with. I'd rather not have to wait months again for another RPi.

GIGObug
Posts: 5
Joined: Wed Jul 11, 2012 1:52 pm

Re: RPi will not power on

Thu Aug 23, 2012 12:53 am

It sounds like you had a power surge.
Please check:
1. There is no short across any of the pins on the micro USB connector.
2. On the bottom of the Pi right by the micro USB connector is a fuse "F3". With no power applied, check for continuity, chances are this fuse is open. The markings on the fuse might mean it's a 'T' slow blow, size '0', 0.75 Amp.
Please report back with what you find.
Note: This is not a self resetting circuit breaker/fuse.

Mnemonicman
Posts: 3
Joined: Tue Aug 21, 2012 6:12 pm

Re: RPi will not power on

Fri Aug 31, 2012 3:24 pm

Can't see any shorts on the micro usb connector.

And as far as I can tell there is current going through the fuse marked T075. And while browsing the forum there was mention of checking the voltage between TF2 and F3. http://www.raspberrypi.org/phpBB3/viewt ... =28&t=7799
Still the same voltage.

Now in a bout of curiosity and boredom I tested the Vbus and GND pins on the micro usb port. Again the same voltage. If that's the case then is it possible the port is damaged in some way?

http://www.petervis.com/Raspberry_PI/Ra ... upply.html

obcd
Posts: 917
Joined: Sun Jul 29, 2012 9:06 pm

Re: RPi will not power on

Fri Aug 31, 2012 4:08 pm

So, you have the same voltage on both sides of F3 and it's only 1.19V?
In that case, it looks like your supply is only providing 1.19V since the Fuse is the first component connected to it.
Or, your micro usb connector can be bad as well, but in that case you would expect no voltage at all.
If something is toasted on the Pi and using to much current, it should trip the F3 fuse and you should measure a different voltage between both sides of that fuse.

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RaTTuS
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Re: RPi will not power on

Fri Aug 31, 2012 4:22 pm

try powering via the gpio?
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