Resolved DTX500 - The sensitivity of the snare is too low!! HELP!

Hi there,
  I have 2 yamaha drum sets, 1 dtx502 series and dtx500 series. And the sensitivity of the snare of dtx500 is too low. I read a manual and pressed "SHIFT+DRUM KIT" and set up the gain to 99(max) and MVI to 65 (20 MVI is loud enough for other pads) but it's not sensitive. When i strongly hit it, it produces sound but doesn't make any sound when i hit it normally. This is not the issue with the snare pad or cable (It works very fine when i connect it to dtx502). I've done the factory reset and nothing changed. Can i get any help?? Thanks!