Emu XL-7 & MP-7 User's Group

Hello,

I've had an XL-7 for a couple years with the standard SIMM ("XL7"), and I just bought a PX-7 with standard SIMM ("DRUM") plus the Vintage/Classic Keys SIMM ("VROM"). Both run OS 2.00 as far as I can tell.  Both standard SIMMs are fine, however, here are my two dilemas:

1) When the "VROM" SIMM is in the PX-7 box, it makes this harsh cycling effect (it's either like a filter sweep or distortion every few seconds).  I was thinking the previous owner hit some setting by accident but I've checked everywhere.  I'm also thinking it may have to do with the subtle software difference in the PX-7 since it's the "drum edition".  The VROM sounds great in the XL-7 box, which leads to the other issue.

2) No matter what configuration I try, if I try to use mix and match other SIMMs with the standard XL7 SIMM, the "XL7" SIMM doesn't show up when I boot. Like if I try to load XL7 and VROM in either box, I only get VROM.

Any advice on either issue would be a serious help.  Thanks in advance!