We purchased an Azden FMX-42u field mixer for some low-budget local work that we do. It seems to be working fine except that the needles barely move. The levels going into the camera are fine, as does listening in on the headphones. We shot some interviews and I had to trust my ears that the levels heading out to the camera were OK (they were fine).
The needles are at the correct level when sending a 1khz tone. But to get the needles to move when recording you almost have to have the mic in front of your mouth and shout.