Yamaha DTXpress/DTXplorer/DTXtreme

opened up my new drums that my wonerfull wife got me and 2 things 
are wrong. (yamaha dtx 2.0)

1.) no power cable, i found another 12v one at the house so that 
problem might be fixed.

2.) I can hardlely hear anything even with the volume at 100%

I reset all factory settings and i goofed around with sesitivity and 
all that stuff, nothing makes a difference, it's turned all the way 
up and the sticks hitting the pads is still audible with my 
headphones on. ANy suggestions, i did a search function on this site 
and 2 others and found nothing to try that i didn't think of already.

headphones are 24 ohms so i should be good there and i tried another 
12v power supply (this one was 3amps instead of 1 amp) and the drums 
sound the same. Also, I pluged in my powered 2.1 computer speakers 
and even with their amp turned all the way up the drums were still 
very, very quiet. I went into the settings and turned the volume 
from 100 to 127 and slid the volume knob all the way up and still 
nothing, they were the same volume with the internal volume setting 
at 127 as they were at 100. Do you guys think I got screwed?? These 
are used. But the guy packed them perfectly (bubble wrap, peanuts, 
seperat boxes)and even supplied an extra pad becouse he said one 
just didn't "seem right", i mean this guy seems sincere. I'm about 
to email him but please, if you guys can think of anything that 
might work tell me, I'll try it. Thanks.

What do you guys think????????????