Emax

Hi all.
I have the same problem with both my emax's
I have a Emu emax SE & a Emu Emax HD SE

The Emax's have a pulsating sound
If i hold down a pad, less than a second intervals 
it has a skipping sound.

::::what ive done so far::::
ran all diagnostics
recalibirated the things in the menu <master 8,8, recalibrate>
disabled all channels except 1
they have the short ribbon that dosent pick up Radio Frequencies

is this the E-chip or filter chip??

thanks Stephen