TU80 and F880 magtapes, cleaning and usage?

Hello, I've connected a Cipher F880 to a qbus pdp11 using a Emulex TC02. Althrough I've got the complete doc for the TC02, I can't get the drive to work correctly. The OS is 2.11BSD, and the error message is: ts0: hard error bn0 xs0=350<MOT,ONL,IES,PED> xs1=2<UNC> xs2=100000<OPM> and somtimes a bn280 I get this message when writing or reading the tape, using tar or dd. I've configured the TC02 to factory defaults, except 22bit addressing is enabled. But should I select Streaming or Formatted mode ? The speed select is currently set to > 50 ips, should I set it to 0-50 ips? Of course it could be the F880, so I tried to use the TU80, but it does not make a big change. The TU80-test (test 01) uses a write-enabled tape to test the drive, sometimes it stops with error code 04 or 06 (the manual is not very specific: error codes 0-9 are read/write errors) and sometimes a 12 (hub not latched). Could it be that my tapemeadia is bad? I've got a Burroughs tape, labeled 23Mar79, and a couple of old tapes form 'eastern germany' without any date. How should I clean the heads of the tapedrives? (used some cleaner for tapedecks) And for the TU80, should I clean the small holes for the air-bearing? I'm not really used to use this kind of gear, so I don't know the common problems using tapes. Regards, Lothar