Raspberry Pi Forums

I always had to cycle power (Nokia PSU, 5 V, 1200 mA) more than once to boot the RPi (archlinuxarm) after a reboot or shutdown - very annoying, but have got used to it. Today I installed some software and typed "reboot". Again as always the system hung up after going down, nothing new. So cycle power - once, twice, ... a couple of ten times, no chance. Okay, just plug it off and wait a few minutes. Plug it in again. No chance, the system doesn't boot anymore.

Sorry, folks, I don't know how to treat this system to be usable. Every (re)boot is a nail-biter, that's too much suspense for me. What am I supposed to do now? Reformat the SD card. Man, after all the config work I did? Buy another SD card? You're kidding, aren't you...

Guess, I'll go out now for a beer to cool down a bit...

Regards
poseidon

Shlurp the sd card image onto your pc and write it back to anew one to avoid a rebuild
What peripherals have you got hung off your raspi?

Debian is ultra stable, I know it's not what you want to hear, but it works. Also Kingston 8gb car works and is solid.

Keyboard and mouse. Disconnected them to see if that makes things better. Even disconnct the display, no success.

As for the sd card: It's a sandisc which may be considered not being the worst of all that sd card rubbish out there. Again, choosing sd cards as the boot medium was a bad design decission, im quite sure.

As for my distro: use arch on my desktop machine (well, actually it is a notebook) for almost two years now: sw develeopment as well as office stuff. Tried a lot of linux distros, debian being among them. The day i stop using arch will be the day i stop using linux.

Regards poseidon

First thing I would suspect isn't the software, but the board power, and the power of the "legacy" USB devices, the keyboard and mouse must be simple one hundred mA devices, (so no special functions, mouse output ports, or lighted keys), just a barebones keyboard, and mouse.
Second thing would the PSU, which must be up to the task of providing 5 Volt, that is "5 dot zero zero volt", not 4.9 volt, at the required current consumption of at least 500mA for the PI alone, but lets say 700mA with two 100mA USB devices. That means you either have to use a very good designed 5V 700mA supply, or better a 5V 1.5A supply.

I have already recognized that RPi is a diva. But the kb is bare none, i.e. One key less and it is useless. Mouse is bare bone - well, a scroll wheel is sitting between the two mouse buttons. Should be okay even at an RPi.

5.00, okay I'll check that. But how then would this device be used with robotics, let alone with mobile robotics? Will 5.5 be okay? Because 5.5 or more is necessary if you dont want the voltage to drop below 5.00.

IIRC your target audience are children. Are you sure you will hit your target audience? Children, used to hw working out of e box? I am in heavy doubt.

Regards
Poseidon

Well, you are making it harder for yourself by sticking with Arch. Debian is in a better state at the moment. Arch does work of course, not trying to take anything away form the efforts there.

And at the moment, the Raspi is in development mode, so almost certainly is not yet ready for our target audience.

There's too much risk in using an over-large voltage, the Raspberry Pi will work fine with anything down to 4.75V according to the spec. In fact I found mine working OK at 4.4V, although maybe I had to boost the HDMI to work there and it is way out of spec.

I also found that, with a keyboard, mouse and ethernet connected, my RaspPi was still only taking 400mA, so even a 700mA power supply is plenty big enough, if it is well designed; there are a good number of cheap, wrongly labelled supplies out there. Which is why there is the advice on here to get something beyond 700mA. That's no guarantee of course, it's just as easy to mislabel a supply 1A as it is 700mA. The best advice is to buy a branded product from a company that has the knowledge, resources and desire to test it itself. So something branded by a phone manufacturer or something from RS or Farnell for example should be trustworthy. In which case all you need is 700mA at 5V.

@jamesh: this has nothing to do with the distro. The device does not boot. No green led, just the red one. No prompt, not even a signal to the screen. So it doesnt e ven bootstrap.

@rurwin: it is the power supply of a nokia n97. There it worked flawlessly. So it should do with an RPi as well.

Regards
Poseidon

poseidon wrote:@rurwin: it is the power supply of a nokia n97. There it worked flawlessly. So it should do with an RPi as well.

Providing some volts to charge a phone is one thing, being a stable power supply providing at least 700mA at 5v is another. Please don't dismiss our experience with troubleshooting, we get most people going in the end. I'd strongly recommend trying a different power supply if you can lay your hands on one.

poseidon wrote:@jamesh: this has nothing to do with the distro. The device does not boot. No green led, just the red one. No prompt, not even a signal to the screen. So it doesnt e ven bootstrap.


Regards
Poseidon

If the distro on your SD card is trashed you will just get PWR. For the green OK led the installation needs to be at least partially working.
I also suggest Debian with a different power source.

I have several power sources here, but none of them has this micro-nano-or-whatever-tiny usb-plug. Any recommendations for power supplies? Had a look at Amazon. But which one will work with my RPi? What do you use?

Regards
poseidon

poseidon wrote:I have several power sources here, but none of them has this micro-nano-or-whatever-tiny usb-plug. Any recommendations for power supplies? Had a look at Amazon. But which one will work with my RPi? What do you use?

Regards
poseidon

I ordered mine from RS and it came with the Pi.

Just for the record, the details on the plug are:-

Switching Adapter
Model:HNP06UK-MicroUSB
Input 100-240v - 50/60Hz 0.3A
Output 5.0V - 1200mA
MN Power Germany
Made in China

On the side is an RS sticker with 7263069

I have an old analogue volt meter.
The charge across TP1 and TP2 is 5V.

I have a 5V 1.0A PSU with a more traditional-style "barrel" type power connector. I didn't want to chop it off and solder on a micro-usb plug, so what I did is chop a normal USB extension cable in half, solder up the power-lines from the female USB half to an appropriately-sized female power socket, and then use a male USB->mini-USB and a mini-USB->micro-USB adaptor. Looks a bit clunky, but works fine. And also means I can easily use a more powerful PSU ( http://www.maplin.co.uk/low-power-multi ... pply-32754 ) if needed.
If taking this approach, always double-check that you get your positive and negative connections the right way round

I haven't received my Pi yet but I've bought what I hope is decent power supply for it. It's a USB wall-wart from Maplin, giving up to 2500mA output at 5V (Maplin item code: N32FU). Currently retailing at GBP 14.99, it's claimed to have stabilised output, with low ripple and low interference.

The only drawback with it is that has a Mini USB connector fitted on it, rather than a Micro USB one. However, Maplin also do a Mini USB to Micro USB converter (Maplin item code: N35JQ). This is currently on offer at GBP 4.99 in Maplin stores.

So for a total of GBP 19.98, you can have a pretty powerful PSU for your Raspi.

Disclaimer: I have no connection with Maplin other than as a customer.

Please test your power supply using this method: http://elinux.org/R-Pi_Troubleshooting# ... r_problems

I'm using an HTC charger rated at 5v/1000mA and with Ethernet, KB, and mouse it's really only 4.74-4.76/700-800mA. When I plug in a USB hub (powered or not) it becomes very unstable.

I have a feeling finding a reliable, stable power supply is going to be easier said than done for many Pi owners.

I have a feeling finding a reliable, stable power supply is going to be easier said than done for many Pi owners.

Agreed, they all seem to be made for mobiles. And the situation seems even worse to me if it comes to SD cards.

Regards
poseidon