jmadero
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Why Default Answer is "sounds like power issue"?

Wed Oct 31, 2012 9:25 pm

Hi All,
I've had several issues now that people have suggested I have a power supply issue....these issues were QUICKLY resolved just by leaving Raspbmc and going to Xbian (such as my wireless keyboard not working).....I just wanted to voice concern that someone who is less of a computer person might just accept the advice, buy new power supplies, and end up having the same issues because it has nothing to do with power and instead is just a matter of changing distros.....just wondering out loud :)

Wendo
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 6:34 am

It's because, at least in the very early days, power supply _was_ the problem in probably 90% of cases.

Cell phone charges really aren't designed to be real power supplies for devices, and so they caused a LOT of problems.

Obviously in your case that wasn't the issue, and it's good you found the solution yourself

Leo Rest
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 6:52 am

Just for balance. I've had zero issues with raspmc using a wireless keyboard/mouse combo. Also CEC control over hdmi worked out of the box from day one.

ski522
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 11:11 am

jmadero wrote:Hi All,
I've had several issues now that people have suggested I have a power supply issue....these issues were QUICKLY resolved just by leaving Raspbmc and going to Xbian (such as my wireless keyboard not working).....I just wanted to voice concern that someone who is less of a computer person might just accept the advice, buy new power supplies, and end up having the same issues because it has nothing to do with power and instead is just a matter of changing distros.....just wondering out loud :)
I agree...even now I still see the default answer being the power supply when it turns out to be something else.

As for cell phone charges not working, that's a bogus comment...like every charger some are better than others. If a cell phone charger as a UL mark (or similar agency) then it has meet the power output the charger specified.

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RaTTuS
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 11:26 am

because , even now , a lot of issues are to do with power,
I have a fine working setup
however when I measure tp1 tp2 I get 4.4V this works fine, [even though it is below spec i.e. 4.75 - 5.25 ] it is powered by a USB hub with a HD plugged into it if I plug a wireless adapter into the hub the measured power is the same but after a while I will get a few errors and soon after the HD will not write something properly ///so I'm right on the edge for my setup @ 4.4V
it's a lot of YMMV

on another way of powering it it works fine and the power is measured @ 4.83

so I think that there are a lot of issues that making sure the power is fine is a good start/
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX
Covfefe

lewmur
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 5:15 pm

ski522 wrote:
jmadero wrote:Hi All,
I've had several issues now that people have suggested I have a power supply issue....these issues were QUICKLY resolved just by leaving Raspbmc and going to Xbian (such as my wireless keyboard not working).....I just wanted to voice concern that someone who is less of a computer person might just accept the advice, buy new power supplies, and end up having the same issues because it has nothing to do with power and instead is just a matter of changing distros.....just wondering out loud :)
I agree...even now I still see the default answer being the power supply when it turns out to be something else.

As for cell phone charges not working, that's a bogus comment...like every charger some are better than others. If a cell phone charger as a UL mark (or similar agency) then it has meet the power output the charger specified.
A cell phone charger can be of the highest quality and NOT work as a PSU for a Pi. A LOT of cell phones don't require anything like .7A to charge and therefore, even though well built, don't furnish enough current to run a Pi reliably. Even some tablet's chargers don't have a high enough current rating.

And, as another poster pointed out, PSUs are the "default" answer because they have been the major cause Pi problems. Nobody has suggested that buying a new PSU will solve every problem. But it doesn't make since to tell someone to try another distro when the distro they're using is being used by many others without any problems.

W. H. Heydt
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Re: Why Default Answer is "sounds like power issue"?

Thu Nov 01, 2012 10:35 pm

At this point, if power quality is suspected of being the issue, for people in the US I tend to recommend trying the Adafruit power supply. This is on several grounds...

Adafruit has developed a good reputation for their Pi addons.

They specifically designed the power supply to not only work well with the Pi (regulated power to 1A), but they also designed it to try to deal with the other major cause of power problems: cheap/flaky power *cables*, They've done this by setting the output to the upper limit of the specification, 5.25v. The prices is also favorable at $6.

eyebee
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 2:35 am

I second the Adafruit recommendation based on personal experience. And if you are not sure if power is your issue, stick a multimeter between TP1 and TP2 and look at the voltage for yourself.

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johnbeetem
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 4:09 am

Power issues are quite common, though it's often the Micro USB cable that's the culprit rather than the power supply itself. Occasionally it's polyfuse F3.

The advice I always give is "start with the Troubleshooting Wiki": http://elinux.org/R-Pi_Troubleshooting# ... F_Start-up

It covers the common start-up problems, and keeps improving as Razzers contribute to it.

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Casalor
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 9:38 am

johnbeetem wrote:Power issues are quite common, though it's often the Micro USB cable that's the culprit rather than the power supply itself. Occasionally it's polyfuse F3.

The advice I always give is "start with the Troubleshooting Wiki": http://elinux.org/R-Pi_Troubleshooting# ... F_Start-up

It covers the common start-up problems, and keeps improving as Razzers contribute to it.
Many of the USB cables I've tried are not suitable. For example, I tried my partners Kindle charging cable with no luck at all. A high proportion of cheap cables have wire that are almost as thin as human hair.

techpaul
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 10:40 am

ski522 wrote:
jmadero wrote:Hi All,
I've had several issues now that people have suggested I have a power supply issue....these issues were QUICKLY resolved just by leaving Raspbmc and going to Xbian (such as my wireless keyboard not working).....I just wanted to voice concern that someone who is less of a computer person might just accept the advice, buy new power supplies, and end up having the same issues because it has nothing to do with power and instead is just a matter of changing distros.....just wondering out loud :)
I agree...even now I still see the default answer being the power supply when it turns out to be something else.

As for cell phone charges not working, that's a bogus comment...like every charger some are better than others. If a cell phone charger as a UL mark (or similar agency) then it has meet the power output the charger specified.
As others have pointed out there are many grades of USB cables used to connect the two from good to down right ugly.

However a charger is not a PSu and can meet a UL marking because its max charging current could be 1A but automatically reduces current and/or voltage as it warms up or oiver time, some charging schemes only expect the max current for a few minutes on the most discharged battery. This depends upon battery technologies use and where the charge control circuit is located and the charger design.

A PSU meant to continuously supply upto max current at specified voltage a charger does NOT have to.
Just another techie on the net - For GPIO boards see http:///www.facebook.com/pcservicesreading
or http://www.pcserviceselectronics.co.uk/pi/

ski522
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 4:35 pm

techpaul wrote:
ski522 wrote:
jmadero wrote:Hi All,
I've had several issues now that people have suggested I have a power supply issue....these issues were QUICKLY resolved just by leaving Raspbmc and going to Xbian (such as my wireless keyboard not working).....I just wanted to voice concern that someone who is less of a computer person might just accept the advice, buy new power supplies, and end up having the same issues because it has nothing to do with power and instead is just a matter of changing distros.....just wondering out loud :)
I agree...even now I still see the default answer being the power supply when it turns out to be something else.

As for cell phone charges not working, that's a bogus comment...like every charger some are better than others. If a cell phone charger as a UL mark (or similar agency) then it has meet the power output the charger specified.
As others have pointed out there are many grades of USB cables used to connect the two from good to down right ugly.

However a charger is not a PSu and can meet a UL marking because its max charging current could be 1A but automatically reduces current and/or voltage as it warms up or oiver time, some charging schemes only expect the max current for a few minutes on the most discharged battery. This depends upon battery technologies use and where the charge control circuit is located and the charger design.

A PSU meant to continuously supply upto max current at specified voltage a charger does NOT have to.
Don't think I've ever seen a cell phone charge that had the charging circuitry in the supply...maybe older ones. Also I agree that cell phone charges generally do not provide enough power. One thing Raspberry PI should do is stack a piece of paper in the box that says "Board requires 5V 700mA -1000mA power supply"

itimpi
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 5:03 pm

ski522 wrote: Don't think I've ever seen a cell phone charge that had the charging circuitry in the supply...maybe older ones. Also I agree that cell phone charges generally do not provide enough power. One thing Raspberry PI should do is stack a piece of paper in the box that says "Board requires 5V 700mA -1000mA power supply"
I have had several from Farnell, and they all came with a sheet of paper that in the Warnings section had a statement of needing 500-700mA for Model A and 700-1200mA for Model B.

Dilligaf
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 6:27 pm

Well, reading over the original thread here http://www.raspberrypi.org/phpBB3/viewt ... 70#p206470 I don't see people blindly saying it's a power problem. I do see people putting out an effort to help you and suggesting you investigate your supply voltage. If you take that as blindly saying it's a power problem then............ As to the fact that changing distros has seemed to fix your problems that does not rule out power as your problem as different distros can cause more or less load on your Pi. Anyways I'm happy for you that you got a working solution however you did it.

NOTE: Yes, I am a moderator on the Raspbmc site, I choose not to play the distro wars game and feel that the more choices the end user has the better.

jmadero
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Re: Why Default Answer is "sounds like power issue"?

Fri Nov 02, 2012 8:20 pm

Thanks to everyone! This wasn't meant as an attack against advice (I don't know what I would do without forums, I think I belong to at least 15 ;) ). Just was a quick question. I may look into the power supply recommended that has a good reputation with Pi, although the HTC Evo3D charger seems to be doing the trick. I just successfully got the turbo mode running and power doesn't seem to be an issue.

Thanks again to everyone! Hope you're all having a great Friday

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