main

main@lists.alug.org.uk

10364 discussions

Re: [ALUG] Testing 5V USB supplies for RPi usage
by Phil Ashby 28 Jan '13

28 Jan '13

On 28/01/13 12:00, Mark Rogers <mark(a)quarella.co.uk> wrote: > On 27 January 2013 01:04, Anthony Anson <tony.anson(a)girolle.co.uk> wrote: >> Have a look at www.maplin.co.uk/ and see if (offers) N66JU; A92JH; A83LA >> float your boat. > > Just to make it clear (because I don't think I did from the outset), > it's not that I'm having a problem sourcing supplies that will keep > the RPi going - I have some that do and some that don't, it's that the > current method of testing (plug it in and see whether it crashes) is a > bit inexact, and the correct method (read the label to see what > current it's rated at) isn't working because the labels can't be > trusted on some of them. > > Also, there's the option of complaining and getting a refund on ones > that are no good, and having a measurement to back me up always helps. > And finally, perhaps more importantly for me, its the opportunity to > learn how to get the measurement. Sounds like a job for a dummy load and a voltmeter? Unless the crash isn't down to sustained low voltage but surge capability, dunno if the Pi has a current surge rating. There is a nice write up here: http://elinux.org/RPi_Hardware#How_Can_I_tell_if_the_power_supply_is_inadeq… Phil.

2 1

Testing 5V USB supplies for RPi usage
by Mark Rogers 28 Jan '13

28 Jan '13

I have several 5V USB supplies, which if the labels on them are to be believed will supply anything from 1 to 2.5A, although I have serious doubts that I can believe the labels. Based on how sowly they charge my phone I think some that are labelled 2.5A are more like 200mA... They're from various sources, which include the likes of eBay. Some will power my RPi, but only if I don't try to plug in a USB device as well. Assuming very little in the way of electrical knowledge (which I guess is obvious as I don't know the answer to my question), what's the "best" way to see what current a power supply can deliver? I have a multimeter, and could doubtless obtain some resisters (or other components) if I need to. I also have a shiny new temperature controlled soldering iron that's never been used if that helps :-) -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

5 16

Re: [ALUG] Colour Laserjet printer problem
by Barry Samuels 28 Jan '13

28 Jan '13

On 25/01/13 22:13:44, Jenny Hopkins wrote: > On 25 January 2013 16:33, Barry Samuels > <bjsamuels(a)beenthere-donethat.org.uk> wrote: > > I have an HP Colour LaserJet 4500 and recently it displayed a message > > to the effect that the black (K) toner was low. I have configuration > > set to continue until toner runs out but before that happened it > > started to show grey bands vertically down the page. < snip> > I changed my HP printer black cartridge the other day and it still > only printed grey faded stuff, so I used "sudo hp-clean" provided by > hplip package, ran clean twice from the gui that popped up, and all > was well (debian 6). > > Jenny I think that that is applicable only to inkjet printers and mine is a laser but thank you for trying. -- Barry Samuels http://www.beenthere-donethat.org.uk The Unofficial Guide to Great Britain

1 0

udev and hdparm
by Barry Samuels 28 Jan '13

28 Jan '13

I have two sata backup drives which I use for daily rsync backups. As the drive is running for a relatively short time during the night I don't want it rotating for the rest of the time. hdparm -S 12 /dev/sdb will set the spindown to 1 minute after the last use and that works from the command line. However I would like the command to be automatically given when the drive is inserted and reading on the Internet suggests using UDEV. I've put this in a .rules file: # Set spindown time for backup drive when inserted. KERNEL=="sdb", RUN+="/sbin/hdparm -S 12 /dev/sdb" But that doesn't work i.e. nothing happens. When I first tried I put only one = after KERNEL and UDEV complained so I know it is being 'seen' and the drive is always 'sdb'. Should it work? -- Barry Samuels http://www.beenthere-donethat.org.uk The Unofficial Guide to Great Britain

1 0

Colour Laserjet printer problem
by Barry Samuels 25 Jan '13

25 Jan '13

I have an HP Colour LaserJet 4500 and recently it displayed a message to the effect that the black (K) toner was low. I have configuration set to continue until toner runs out but before that happened it started to show grey bands vertically down the page. I decided to change the toner in the hope that it might cure the problem but it didn't. I can see rings of toner around the imaging drum if I take it out. It does seem to be picking up surplus toner but I've no idea where from. At present I have: Transfer Kit showing 96% life left Fuser Kit showing 91% life left Drum Kit 68% lif left Any suggestions would be appreciated. If you suggest cleaning something would you please explain where to find it because I probably won't know. -- Barry Samuels http://www.beenthere-donethat.org.uk The Unofficial Guide to Great Britain

2 1

MySQL select into
by Mark Rogers 22 Jan '13

22 Jan '13

Any MySQL gurus here? I have a table: `item_uid` INT (Primary key) `cat_uid` INT <several other fields> What I want to do is take all records where cat_uid=10, and insert them back into the table with cat_uid=11 (in other words duplicating "category 10" as "category 11". What I had was: CREATE TEMPORARY TABLE tmp SELECT * FROM myTable WHERE cat_uid=10; UPDATE tmp SET cat_uid=11; INSERT INTO myTable SELECT * FROM tmp; This used to work when I didn't have the primary key `uid`, but now this just attempts to insert duplicates for the uid field and fails. The following works instead: CREATE TEMPORARY TABLE tmp SELECT * FROM myTable WHERE cat_uid=10; ALTER TABLE tmp CHANGE uid uid INT(11) NULL DEFAULT NULL; UPDATE tmp SET uid=NULL, cat_uid=11; INSERT INTO myTable SELECT * FROM tmp; In other words, alter the tmp table structure to allow the uid field to be NULL, and as part of my update set all the uid's to NULL, so that the final insert tries to insert NULL for uid which causes MySQL to insert the next auto-increment value instead. But this seems very convoluted, is there a "correct" (or just "better") way? -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

2 4

Summat up with Mint - or Mozilla
by Anthony Anson 21 Jan '13

21 Jan '13

Using the most recent Thunderbird, ditto Firefox, the system freezes frequently when I have T/bird and F/fox running at the same time. F'rinstance today, I left T/bird running while I went to the BBC website. There I filled in an online comment and then tried to close Firefox, which declined to play nicely, and none of the usual rollover dialogue boxes on Mint functions worked - connection speed, state of battery etc just sat there glumly ignoring the mouse pointer. File and Quit on the function bar closed Firefox, but nothing would shift Thunderbird. Three-fingered salute deleted the last two e-mailsin my inbox... Had to power-down to regain control, but the e-mails seem to have vanished entirely. (Not in trash, nor in any other folder.) Anyone any bright ideas? (Apart from not running Firefox and Thunderbird at the same time...) -- Tony

2 4

?Ubuntu 12.10 Boot Issues
by steve-ALUG＠hst.me.uk 21 Jan '13

21 Jan '13

Hi all, I was on an old version of Ubuntu, started getting messages about it not being supported any more and so decided to update. I decided to install the lubuntu-desktop package, then do updates until I was up-to-date. So now, I'm up to Lubuntu 12.10. When I booted it, it hang big-time before getting into the GUI. I Hard-booted and selected a different kernel, and it booted fine. After experimentation it seems that booting into the kernel described as "Ubuntu 12.10, kernel 3.5.0-10-generic" causes the machine to hang before getting into the GUI. I've just tried making LUbuntu and XUbuntu 12.10 CDs and booting from them, but both of them hang, I presume when trying to load the Kernel. Trying to boot via the "kernel 3.5.0-10-generic recovery mode" boot menu option also hangs. I've not had a problem like this before. Does anyone have any advice on diagnosing what's causing this hang? Any logs to examine would have to survive a hard-reboot, or are there any debug options I can put on the grub boot line. Or am I doomed, or have to wait for a new kernel to come out, or keep using the old one. Any advice or comments would be appreciated. I haven't googled much as I don't quite know what to search for (you may tell me I'm a numpty for this!) Hardware is a Dell Lattitude D410. Cheers Steve

3 5

[ALUG Announce] 3rd Monday Monthly Ipswich Social Meeting : The Mulberry Tree
by samwise 21 Jan '13

21 Jan '13

ALUG Announce Please send announcements to Announce(a)lists.alug.org.uk Unsub, change settings via http://lists.alug.org.uk/mailman/listinfo/announce ----- The monthly "Third Monday" ALUG Ipswich Social Meeting is back tonight, 21st January, at 20:00: The Mulberry Tree 5 Woodbridge Road IPSWICH IP4 2EA Tel: 01473 225776 Map/Directions URI: http://maps.google.co.uk/?q=IP4+2EA WWW: https://www.facebook.com/MULBERRYHOSPITALITY The Mulberry Tree, previously known as The Milestone Beer House, is a grade 2 listed building in the centre of Ipswich. It is located at the intersection between Woodbridge Road and the A1156, across the road from the old Odeon cinema and not far from the Regent Theatre. It re-opened on Thursday March 29th 2012 after a major refurbishment, under its original name of The Mulberry House and has already begun to regain a good reputation for its selection of beers and ales. It has a sizeable car park to the rear of the building. All are welcome, novices and experienced users. Feel free to ask for further information on the Main ALUG mailing list. I'm back home and will be out to play today, if anyone wants to join me. :) Cheers, Peter. ----- Send discussion replies to main(a)lists.alug.org.uk (Reply-To set) Unsub, change settings via http://lists.alug.org.uk/mailman/listinfo/announce

1 0

Help with hardware
by Peter Alcibiades 20 Jan '13

20 Jan '13

Any ideas what this might be? I was having a crash with instant power down. So I replaced the PSU with a Xilence, and for a while all seemed well. Then it happened again. Restarted. But to restart, I had to actually unplug the power cable. Only then did the power switch work. All carried along fine for a week or so - I never turn it off, and ir ran just fine. Then just now, it happens again! In the meantime afflicted by a sudden rush of nerves I have made a backup using clonezilla so its not going to be the end of the world if it goes south. What happens is, try to use the power switch and nothing whatever happens. Then I connected up to a different power cable and a different socket, and it goes on. The Gigabyte board asks me to pick the last good boot, so I do. Then it powers down and restarts, and goes into the usual Debian login, after which it runs the disk diagnostic and repairs itself, and now its running just fine again. What on earth could it be and what should I do? See what is weird is that I am tempted to think maybe its the extension block, but the screen runs off that, and that is just fine. It seems reasonable to change out the extension block because they are not expensive. But I can't quite see how that could do it. There is no doubt that last time it was the psu. It was totally dead, and replacing that first with the evo and then with the xilence, it did actually bring it all back to life. But this time its clearly not the psu, or could it be? Al

3 4

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

main