Hardcards
are nice if they still work (the drives are dying).  
 Actually, a lot of them use programmable eeproms and it is those that
 are dying.  I have a lot of Plus hardcards with fully working drives,
 but the electronics are bad. 
 
 That should be easy enough to fix...
 Read the ROMs off a good one and burn a new set for the broken ones, no?