Hi. Okay, I'm going to chime in just in case no Surge owners respond. I have a MKII Pro kit, and have had my trigger fail, so I replaced it. I took off the mesh head, and on my pad, the trigger is indeed below the center. In fact, the center has a large foam cylinder that takes the beater hits, and the vibration transfers to the piezo trigger mounted on a smaller foam cylinder below the larger one. If you hammered the piezo directly with a kick beater, it would probably die rather quickly (faster than it will normally die). So at least on the DM10 MKII kick pad, this is the configuration. Take your head off and see how it's assembled. That will help you with determining what's going on. On my particular unit, the smaller foam cylinder (with the piezo mounted on top) began to compress and tilt off to one side. That created uneven and muted response. I used a more dense foam (only slightly- you still want some give) to build a new cylinder. Replaced the trigger with a more robustly wired transducer, and it works like a champ.
Considering how Alesis makes their pads, you probably have something similarly-configured. Just be aware that the trigger might be lightly stuck to the inside of the mesh head. On mine, they used a double stick tape of some sort. I just gently worked it off until the head was free. When I put it all back together with a new trigger, I didn't use adhesive on the face of the trigger unit. Just make sure it's in contact with the head.
If this is a new kit, and you have things falling off internally, let Alesis know and they "should" help you out. I have received quite a few free replacement pads to replace the ones that failed. Crappy build quality, but pretty responsive customer service.