RPi Seems to have died

[Pyk]

Firstly, I'm just wondering if this is where I should be posting questions about the Raspberry Pi itself and if not, where should I be asking? The RPi was originally from adafruit as were the peripherals I have been using with it.

If it is, here's a brief description of the problem:

Currently, when I plug it in the PWR light will light up red momentarily and then go out. The longer it's been unplugged for, the longer the light goes on with a maximum of around 6 seconds. The board near the power supply continues to heat up (component F3 seems to be the source of the heat) which suggests that the plug is making contact fine.

However, I have tried a few different power supplies and a few different cables all with the same symptoms. A couple iPhone chargers, an iPad charger, and various other USB plug chargers that I've accumulated over the years.

The only thing I've used with this RPi other than a keyboard mouse and monitor, is the adafruit mini thermal receipt printer plugged in to ground, TXD and RXD through an adafruit Pi Cobbler. It's been running fine for a few weeks now automatically printing out my instagram feed. For the past week the RPi hasn't even had a keyboard, mouse, or monitor as I have simply been accessing it via VNC.

Thanks for any help,
Chris

[adafruit_support_mike]

Based on the schematics here: http://www.raspberrypi.org/wp-content/u ... s-R1.0.pdf , F3 seems to be a 'varactor' or 'resettable fuse'. That's basically a device with low resistance to low levels of current, but high resistance to high levels of current.

The theory is that a varactor will heat up and kill power to the parts of the circut that need to be protected, then allow current to flow again once it cools down. Yours just seems to be heating up, which means the fuse has probably failed.

The good news is that the rest of your Pi probably isn't dead. The bad news is that this might be more of an Element14 issue than an Adafruit issue. I'll send a note to someone farther up the food chain and have them follow up.

[Pyk]

Thanks,

I do recall this has been happening since I got it. I've had two of them and was originally having other issues getting the thermal printer working (mostly which turned out to be my own coding errors) so I was switching back and forth between the two thinking that it was possibly a hardware problem. I'm guessing this specific issue I only had with one and the other one (which I've currently lent to a friend) is perfectly fine.

It wasn't working even a day or two after my original post, but I've tried starting it up just now and it's back to working again. I'm guessing this is a hardware malfunction that will continue to pop up though.

[adafruit_support_rick]

You might want to have a look at this discussion of power supplies and power problems.
Here is another page which discusses what the blinking LEDs indicate, and offers some tips on diagnosing power problems.

There are also a couple of naughty/nice lists for power supplies and powered USB hubs.

[Pyk]

I did read through this page during my initial search, though reading through it again I had missed the part about the polyfuse needing days to reset. Still, it seems like the main issues with power supplies is not enough current, and using 2A, even 10A power supplies gives me the same results (I've tried at least a dozen at this point, though many of the USB based ones may not have worked because the polyfuse had not reset). The high current supplies do not have USB and using power pins on the GPIO header seems to circumvent the polyfuse.

Maybe I will put my troubleshooting on hold until I can get my second RPi back from my friend to verify these power supplies.

[adafruit_support_rick]

That polyfuse will blow in an overvoltage condition. If you're going to power the Pi through the GPIO, you need to be very confident in the regulation of your power supply, since it is behind all the power protection on the board. Have you checked the voltage between TP1 and TP2?

[gopuar]

similar to pyk. powered up using nexus-7 as power supply. got a red light, no splash, no green lite. disconnected power, usb/mouse/keyboard. powered up again. no red led, tp1-tp2 5.07 v, both sides of f3 have 5.07v.

[adafruit_support_rick]

@gopuar: See this troubleshooting page: http://elinux.org/R-Pi_Troubleshooting# ... F_Start-up

[gopuar]

been there, also thats a nexus-7 power supply w/otg cable.

[adafruit_support_rick]

Can you try a different PS?

[gopuar]

yes, different PS. wall wart 5v 1 a...tp1-tp2 5.1v, f3 5.1v both sides

[adafruit_support_rick]

And still no red LED? Your 5V -> 3.3V linear regulator must be blown. Did this thing ever work? How else have you powered it besides the Nexus wart?

[gopuar]

no lites, no red led, only used nexus-7 ps which is tagged as 5v 2a 'til you suggested otherwise. as far as working i got the red led when i first powered up, no other lites, no splash. powered down and that was it, no lites after that.

[adafruit_support_rick]

@gopuar - please email support@adafruit.com with a link to this thread and ask for a replacement.

[Pyk]

I've gotten my other RPi back, time to compare.

On the working one, TP1 and TP2 show 4.88/4.89 consistently for the past hour or two of running.

On the broken one, TP1 and TP2 never show the same value twice. Right now, starting it up after not running for a week, they start at 4.1V and slowly decrease to 4.0. Usually they continue to slowly decrease until the unit turns off. The last time it was in red light mode, they showed 1.42V.

I would like to be clear that I only ever tried powering it through GPIO after consistently having this issue, and I only ever powered it with supplies that my other RPi has no issues with.