I just received the 20G Rio Car I ordered when the price plumetted, dumped some songs into it quickly and plugged it into the car dock that's been there for about a year and a half from when I got my Mk2 Empeg. It does absolutely nothing - no startup screen, no noise, not even the little blinky LED in the corner. The Empeg, however, still works fine if I plug it in. Both units work fine when plugged into the AC adapter.

What kind of wiring problem would cause this symptom where the original Mk2 ermpeg works in the car but the new Rio Car does not? (And just as important, if I get the Rio Car working, does that mean the Empeg will stop working?)

If it makes any difference, the Empeg is one of the very first Mk2's off the line, serial number 080000083, complete with slippy version of the volume knob (although I don't have problems with it) and startup "thump" noise.