MPC 5000 dull recording problems

I just bought an MPC 5000 off the bay and have been using it quite happily until recently I noticed a bit of a drop in volume from the machine. I had a midi keyboard plugged into it and was playing it at the time so thought it might be some weird midi signals causing interference. I unplugged the midi and checked my amp NS10's etc and found everything to be ok.

I was recently recording a Vermona Lancet kick drum into the 5000 and built a kick sound with a sharp attack, like an 808 with the attack turned up to give it click on the head. When I recorded the kick drum and assigned it to a pad the click in the attack was gone and the playback sounded dull. I've tried recording Moog and other synths and it seems to be just this specific type of frequency that plays through the machine for monitoring but then won't play back?

Anyone got any ideas?

CHRIS

Try recording with a bit of silence before the clicky attack, then trim in the MPC to see if you get desired result