Gary,
I have ordered 15 NOS 3M DC100A tapes from EBAY. They are scheduled to arrive Sunday.
I hope the drive bands are still ok - but I may have to replace them with Plastibands.
I will try to format and create a System Verification tape from the files I have recovered and report the results here.
Does your 4041 have the Option 30 Programming Development Option ROMs?
Monty