What was found
AFTER USING GROUND POWER TO POWER THE AIRCRAFT, THERE WAS AN IMMEDIATE AND VERY STRONG BURNING SMELL NOTICED BY ALL OF THE CREW THROUGHOUT THE AIRCRAFT. (FLIGHT 4642 - FILED CLOSED) INSPECTED FWD, MID, AND AFT AVIONIC BAY. PERFORMED BIT TEST OF ALL COOLING FANS PER AMM 45-45-00 ERJ 175. OPS CHECK GOOD AT THIS TIME. NO SMOKE SMELL AT THIS TIME.