Emax

My Emax II seems to load up my samples and works fine for a period. However, sometime 
during my work, maybe an hour later, sometimes a minute later, I lose all audio. 
Sometimes I hear a lil "thud" before it goes, sometimes not. 

Now, I did open it up a few months ago to install a hard disk, which I ended up not doing. 
For a minute there was no nothing sound or lights. I opened it up again and properly 
attched everything and got it working again. Could I have made an improper connection? 

Any feedback would be helpful. I love the sound of this thing. I want it work again, but if 
it's more than I wanna do or spend to fix it, I'll take the loss.

Peace.

homershines