Need to know DDS drive used to write backup tapes

[Steven N. Hirsch]

On Sun, 3 Oct 2004, Zane H. Healy wrote:

> > On that subject, can anyone shed light on what appears to be a common
> > failure mode for DLT7000 drives?  I have (2) which misbehave in the same
> > manner.  At powerup, the head recalibrates (bzzzzzttt), the door lock
> > solenoid activates and the green LED on the bottom right lights. However,
> > all the density and tape type LEDS on the left simply flash in
> > sync approx. 2x per second.  An inserted tape will load, but that's all
> > she wrote.  No track calibration, no shoeshine - nothing.  Exact same
> > symptoms on both units.
> > 
> > One was working until the power was accidently interrupted in the midst of
> > a backup.  The second was a $5.00 swap-meet item picked up in the hope of
> > yielding parts to get the first working <g>.
> 
> I don't happen to have the manual handy, but have the drives swallowed the
> tape leader?  It's a bit of a pain in the neck to restring the leader on a
> DLT7000 compared to a TK50, but it's still not that hard.  When you look in
> the drive, you should see something that looks like the bottom end of the
> following:
> http://zane.brouhaha.com/~healyzh/TK50-Leader.gif
> 

Unfortunately, that's not the problem.  The leader is in place and, as I 
mentioned in my first post, it does properly load the tape and wind 
forward for a bit.  On a working drive, it begins to shoe-shine back and 
forth until it calibrates itself.  The bad drives just sit there blinking 
until I hit the unload button. 

Do these things use holes in the tape to locate BOM, or is it magnetically 
sensed?

Steve