I have a 2002 BMW 540iT. ("T" for "Touring" or what everybody else just calls a station wagon!)
I have had consistent problems with the Phatbox "locking up" when I use any of the buttons that interface with it in a rapid manner.
If I "arrow up" or "arrow down" through an album, or through a playlist too quickly, the unit begins going haywire. It will either jump around the same album I am on, or continue jumping through albums, to finally settle somewhere and then allow no more input from the user. In some bad cases, it will just play bits of songs, then jump to another, do the same thing, jump to another...on and on.
Only unplugging the power into the unit stops the insanity. Once the power is restored after a few seconds, all returns to normal. As long as I don't use the "arrow up" or "arrow down" keys too quickly, I am safe...and this is how I have been living with the unit since I put it in, about 3 years ago. My only caveat is using the "random" mode, and letting it play everything at its own leisure. If I wish to find a song from an artist starting with the letter "S", and I am currently on a letter "A" artist, my only hope is to use the random mode, then arrow up and down...very slowly...for a few songs at a time (taking a minute break between "arrowing"), and hope I land near "S". When I do, I disengage random mode, and then jump SLOWLY to the album and song. It truly is ridiculous and annoying!
This has been this way since day 1 with this unit. At one point, Phatnoise replaced the entire unit with a brand new unit,(phatbox, blitzsafe, cables, etc.) yet the same problem still exists. I have even tried different DMS's in the box...same trouble.
I assume it is most likely some electrical gremlin in my car. I had BMW look into it when the car was still under warranty, but only from a fringe point of view. BMW has a staunch rule against any aftermarket "anything" in their cars. If they find it, they immediately blame any problems you are having on the device, and send you on your way...which sucks, because I truly believe the problem with this phatbox may be the car, but they won't look for anything.
The phatbox is the only thing affected in my car however. No other radio interface problems have surfaced. I have only had one or two occasions of weird annoyances with my car. One where I deactivate the alarm to unlock it, and the flashers come on and won't go off until I cycle through a couple of "turn car on, turn car off" episodes. BMW and my own mechanic have said this is usually due to a drained electrical system due to the car sitting for a few days without being started. (apparently the computer brain is always "thinking"). The other where all interior lights suddenly come on while I am driving, which normally only happens when you open a door, or deactivate the alarm at unlock. Again though, these happened maybe once or twice over the entire ownership experience. The phatbox problem has been consistent, and easily duplicated.
I have posted to BMW message groups (in the audio mods section) concerning this, and asking if others have had similar problems, but have never had a response.
Can anyone here take a guess at what it could be? (I figure if the entire unit and all the that goes with it have been replaced...then it must be my car)
Thanks for the help.