Hardware Documentation - Machines DEC - VAX hardware reference - TK50/TK70 FAQ

Top 4 gems of TK50/TK70 wisdom

Top 4 gems of TK50/TK70 wisdom

What is the difference between a TK50 and TK70

  • A TK50 drive works on TQK50 or TQK70 controller, writes/reads TK50 tapes (known as CompacTape). If you can choose between a TQK50 or TQK70 controller for the TK50 drive, take the TQK70. It's faster.

  • A TK70 drive works on a TQK70 controller, writes/reads TK70 tapes (known as CompacTape II), and can read TK50 tapes (not write).

How to clean a TK50/TK70 drive

TK50/TK70 drives are better dust/dirt magnets than most of the vacuum cleaners in the known universe. Most of the problems you with a TK50/TK70 are due to dirt/dust on the tacho/LEDs inside the drive.

If the drive is dirty, open the metal cover (nothing more), and clean it carefully. In particular clean the 4 LEDs and the area immediately around. Since you already have the drive open check the Take Up Leader (used to feed the tape) is not bent or broken. If you have to replace it, the DEC-PART-NUMBER is 74-28268.

How to erase TK50/TK70 tapes

What you need for erasing a tape:

  • A $1000 bulk eraser, or
  • a $0.20 magnet.

If you can operate your drive outside the computer, remove the metal cover of the drive, and put the magnet near the tape while the drive try to feed the tape in.


This procedure is not without risk, and we accept no responsibility for non functional drives!

If you can't operate the drive open, use the bulk eraser ;-)

Can you reformat TK50 tapes as TK70s

Once you erase a TK50 you can use it in a TK70 drive and vice versa, but the TK50 and TK70 tape material is different, and the write current of the TK70 drive is different (lower). This is not recommended, and should be used for temporary storage for which you will suffer no pain if lost.

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