Positron User's Guide: Troubleshooting

As you might expect, things can and will go wrong with technology. This document will give some hints as to how to deal with problems.

Operating System Issues

A common problem is that you plug my Neuros in to my computer, but it is never assigned a device. There are several possible causes for this:

The required kernel modules are not loaded. Usually most of them are autoloaded, but there are some systems where usb-storage needs to be forced in by hand. The installation guide gives some explanation of how to do this.

lsmod

dmesg

Some kernels just don't seem to work. All the correct modules are loaded, but the usb modules just lock up when a Mass Storage device is attached. This can even be a semi-random failure, like lockups during transfers. Unfortunately, there is not much you can do in this case but upgrade your kernel. The latest kernels (>= 2.4.20) seem to work well.
The firmware on your Neuros might also contribute to this problem. There have been reports that the 1.34 beta firmware causes periodic freezing in Linux during transfers. If this is the firmware you are running, downgrading to the latest stable firmware might help.

Database Problems

Database problems frequently cause the unit to freeze while you are using it, or they cause songs to be missing or misfiled. This is usually caused when the connection between the Neuros and the computer is interrupted during transfer. If the OS freezes, the Neuros freezes, or the link cable is disconnected before you unmount the device, the database can be corrupted. To fix this, use the following command:

positron rebuild

This will reconstruct your databases from scratch based upon the music files it finds on the Neuros. If problems persist, there is a good chance you found a bug in positron. Please report it to us using one of the methods outlined below. You will probably want to zip up your WOID_DB subdirectory on the Neuros and include it with the bug report.

Filesystem Problems

Another class of problems generates errors like:

Input/Output errors (visible using the dmesg program)
Linux thinks the filesystem is read-only.
mount won't recognize the filesystem on your Neuros.
Files on your Neuros have been damaged or destroyed.
The Neuros freezes when playing certain files.

These symptoms suggest the filesystem on the Neuros has been corrupted in some way. Filesystem corruption is usually caused in the same way as database corruption, though it is generally less common. Unfortunately, the best way to fix a corrupted file system is to format the Neuros and start over.

WARNING: The following operation erases the contents of your Neuros and should only be attempted as a last resort.

Disconnect the USB cable between your Neuros and your computer.
Turn off your Neuros.
Press and hold the 1, 5, and Play buttons. You should press the Play button slightly before the other two.
When "SAFE MODE" menu appears, release the buttons and select "Format Hard Disk" if you have the hard disk model or select "Format NAND Disk" if you have the flash memory model.
When the format finishes, select "Exit," and the Neuros will continue its normal boot sequence, and tell you it is creating databases.
Connect your Neuros back to the USB port on your computer. Mount the disk, and run positron rebuild. It is important that you do this immediately after formating because the Neuros firmware produces several incorrect databases after a format operation. The rebuild command corrects this problem.
Your Neuros is now ready for normal use again.

Music File Detection Problems

While we've tested positron on a wide variety of MP3s, sometimes we stumble across one that is not identified by positron, so it will refuse to add it to the Neuros database. Quite often, this is because the file is corrupted in some way. Many MP3 players are extremely tolerant of damaged MP3s, so some of these files are actually playable. At this time, positron has no override switch to allow you to force a file to be uploaded. This may or may not be a good thing because it is unclear how the Neuros firmware would handle such damaged files. Our suggestion is that you try to acquire the file from another source or recreate it using a different tool. Please contact us about problem files: we are interested in improving our detection algorithm if it fails on legitimate files.