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16  Hardware and U-Boot firmware / Hardware / I fixed my Sheeva's power supply (pics, howto) on: September 24, 2010, 07:10:28 PM
I hope this may help those who have soldering skills and want to try their own repair.

My plug's power supply finally quit after a year of solid uptime.  It started with a reboot a few weeks ago, then again several days later, then increased in frequency...  It was an obvious power supply problem.  I took it apart and I found three bad capacitors:



From left to right: 1) 400V, 6.8uF, 2) 400V 22uF, 3) 1000uF, 10V....

This is the power supply.  It was wrapped inside an insulator within a box within another box.  Three easy to replace capacitors evaporated their electrolyte from the heat.  The two on the left were rated at 400 volts, but I had 200 volt caps and that's fine since we are on a 120 volt service.  (120 volts peak to peak is around 180 volts...)  The left was a 400V, 6.8uF and the middle was a 22uF.  I replaced those two with 33uF.  The diodes and fuse have no problems handling the extra capacity.  The real problem was the one on the right, which was 1000uF at 10V.  That one was completely toasted.  I had a 1000uF at 16 volt on hand, which fit well.  These capacitors are polarized, so + and - had to be on the correct side or they could explode.



I placed the power supply back on the housing shell without the protective boxes for extra ventilation.  I also bent a plastic tab back to help with air flow to the external vents.  Doing this may be a bad idea, considering bad things may happen if the power supply gets knocked around and touches the sheeva motherboard.

The motherboard itself was of outstanding quality and construction.  The power supply not so much.  It was more like a cheap off the shelf consumer power supply made to work.  This repair should give more life.
17  General Category / General Discussion / Re: If you ordered your plug recently.. Did you receive it yet? on: September 20, 2010, 05:06:54 PM
This makes me sad.  I've had my sheevaplug for over a year and its a great server.  But I want another to hack software with and don't want to wait months and months for a new baby.  I wish they can keep up with demand.
18  Hardware and U-Boot firmware / U-Boot stuff / Re: startup (start.S) code on: August 17, 2010, 06:30:44 PM
I used to write code for embedded devices.   Writing assembly seemed faster when talking directly to the hardware.  Using the hardware's raw language is often easier to understand exactly what is happening to the last detail.
19  General Category / Marvell PlugIN - Free Your Imagination / Re: Imagine Personal Data on you plugComputer on: August 06, 2010, 09:42:24 PM
You are more likely to get testers if the complete source is in a tarball with the usual LICENSE, COPYING, files...

But that goo is binary.  Who wants to play with that?
20  Hardware and U-Boot firmware / Hardware / Re: Fried SheevaPlug !!! on: June 09, 2010, 02:01:03 PM
I wish my Sheeva also had the option of an attractive aluminum case.  Serious heatsinking.
21  Linux Stuff / General Linux questions / Re: Slow USB disk input output on the Sheevaplug on: June 02, 2010, 11:20:12 PM
I have setup my sheevaplug with ubuntu and root on the USB disk. The Disk is an 1Tb Iomega device.


What is the model number of this Iomega drive?

I had one of those before and had to take it apart and put a new USB controller on it.
22  General Category / General Discussion / My Sheevaplug to date (with a pic) on: May 31, 2010, 03:40:54 PM


I'm using mine as a utility web/mail/file/gnu-screen server in addition to storing pictures from the security webcam.

Had mine for about a year.  Its a perfect fit right onto this UPS unit.  That means I don't have to worry about ripping out wires or moving things.  I'm very pleased with the reliability.  Unlike other computers, there's no worry about ripping wires out or moving it to a new location.

THANK YOU to cbxbiker61 and countless others for maintaining a kernel, installer, and other helpful utilities.  I wish there were more names in the README files.  Good scripts have helped make this run flawlessly since I updated it 52 days ago.  Root is now from a Sandisk 16GB and much faster than I expected.  I have the USB into a hub for the external hard drive so the sheeva may run cool.

Having this little guy at home makes my cell phone more useful too.  I can press the Android Connectbot icon to do a passwordless ssh auth login where gnu-screen is the default shell.  That means hitting a button logs me in right where I left off the last time.  The sheeva has become my remote desktop.

This is perhaps the greatest computer I have seen in my lifetime.  That's my story.  I just wanted to brag about it.  I hope others have good stories to share too.
23  Hardware and U-Boot firmware / Hardware / Re: Poll: Sheeva Plug Power Supply failures - does the mains voltage matter? on: April 05, 2010, 05:28:23 PM
Higher voltage.  Loud boom.  I would wager capacitor failures. Usually a semiconductor failure will activate the fuse without much drama.

Anyone who had a failed one took pictures of the board?
24  General Category / General Discussion / Re: Can't install get installers to talk to the Sheeva on: April 05, 2010, 05:32:51 AM
My ftdi jtag interface would often be loose when it appeared tight and cause problems like this.
25  General Category / General Discussion / Re: Public facing SSH server on: April 05, 2010, 03:10:23 AM
Run snort and you might see a lot of crazy probing traffic.

I remember the old days when getting a portscan was worth waking up and checking it out.  Now its like the neighbor's dog barking.
26  Linux Stuff / General Linux questions / Re: Adding to empty fstab on: April 04, 2010, 09:27:16 AM
If you want a nice list like fstab, but from currently mounted filesystems:

cat /etc/mtab

its the listing of currently mounted filesystems automagically created with the mount command.
27  Linux Stuff / Kernel / Re: NFS on sheevaplug ubuntu on: April 04, 2010, 05:47:16 AM

Thanks!  That found my problem.  Commenting out the kernel support check in the init script and I was able to start a full working nfs.

Interestingly, my first attempt was trying to rm the script and reinstalling failed.  I was able to purge the old nfs setup and reinstall.  From there I was able to "fix" the script.
28  Linux Stuff / Kernel / Re: NFS on sheevaplug ubuntu on: April 03, 2010, 06:16:13 PM
Found this old thread from googling NFS with the sheeva.  I used to run NFS years ago, but this is refusing to work:

Code:
root@dattaway:/# /etc/init.d/nfs-kernel-server start
 * Not starting NFS kernel daemon: no support in current kernel.

I thought this was odd after modprobing nfsd, so...

Code:
root@dattaway:/# zcat /proc/config.gz | grep NFS
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
# CONFIG_NFS_V3_ACL is not set
CONFIG_NFS_V4=y
# CONFIG_NFS_V4_1 is not set
CONFIG_ROOT_NFS=y
CONFIG_NFSD=m
CONFIG_NFSD_V3=y
# CONFIG_NFSD_V3_ACL is not set
CONFIG_NFSD_V4=y
CONFIG_NFS_COMMON=y

It appears to me nfs server in the kernel, but I can't export any services.  What gives?
29  Hardware and U-Boot firmware / Hardware / Re: Underclocking the Sheevaplug on: March 31, 2010, 04:27:57 PM
This looks like a kernel function we could stick in /proc/cpu ....something like the eeepc modules did.  They wrote a module that poked a few bytes into the PLL registers through the /proc interface.
30  Hardware and U-Boot firmware / Hardware / Re: Loose mini-USB connector on: March 22, 2010, 03:21:26 PM
I thought it was a kernel module problem that I couldn't send through the minicom console.  First time I ever had a problem with a USB connector.  I had no idea and took me many months....
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