Trouble with tape drive

Hello.

I have standalone tape drive ( not a library) HP StorageWorks LTO-5 Ultrium 3280  SAS.

For the last 7 days it requested the cleaning cartridge of 5 times.

This tape drive  works more than 5 years and writes on a tape for 15 hours every day.

What happened?   

The resource of head  ended? Or a head so strongly became soiled that the cleaning cartridge helps not for a long time?

1. What to do ? 

My backups can't successfully finished.

2. I have another  standalone tape drive ( not a library) HP StorageWorks LTO-5 Ultrium 3000 SAS.

Now it isn't connected to my server.

How to step by step to enter this device into operation and to reassign all tape pools on it?

Software  Symantec Netbackup Enrerpise version 7.5.0.6 ( Windows 2003 )