[Elecraft] Can MFJ PS be "cleaned up"?

[BobConvers at aol.com]

I wsa given an MFJ-1317 PS, rated to supply 2.89A at 13.8VDC.   However, this 
is apparently not one of the lucky ones, and it puts out lots of hash.   I 
put several ferrite cores on both the input and output lines, with little 
improvement - the hash appears to be coming through the case.   Has anyone had any 
luck cleaning up one of these?   Also, it's not obvious how to open the case, 
and before I use brute force, does anyone have any hints?   TIA,

Bob, WO3E