Vintage Simmons Drums (UK) Users Group

Hello everyone, I'm new to the group and Simmons.  I had used a Tama 
Techstar kit back in the 80's because I couldn't afford Simmons at 
that time.  I recently purchased an sds8 set that "looks" in near 
perfect condition.  Since the techstars were actual heads over foam, 
the rubber over wood is uncharted territory for me.  I need to know 
if the following observations are normal or problems which can be 
fixed.  First, the module has an audible hum which seems to get 
louder as the unit is moved closer to the guitar amp I'm using (I 
would imagine this would be a much bigger problem through a PA 
system).  Second, I'm noticing granular fragments of rubber along 
with pitting in the strike area of the pads.  I know rubber drys with 
age, but since the pads looked like they'd never been played I'm not 
sure if this is normal.  If the rubber has dryed out, is there a 
fix?  Third, when using the pads with an Alesis Dm-5 module (with the 
velocity set at max) it is necessary to use the butt end of the stick 
to get consistent triggering between the four pads.  I'm using 5A's 
with moderate force.  I use an overhand grip and this produces quite 
a stinging sensation on the palm of my snare hand (stick 
reverberation) unless I really keep a tight grip.  Is there a more 
sensitive replacement trigger available?  Fourth, are the pad casings 
stappled to the wood top section?  If so, is there a better method of 
fastening these casings to make access to the trigger easier?

Thanks,
Rich