machine doesn't know it has a tape drive

[DE@PHOENIX.SCH.Symbolics.COM (Doug Evans)]

    Date: Tue, 28 May 1991 11:13 PDT
    From: mwilliam@hawk.ulowell.edu (Marian Williams)

    Hello.

    We just received a 3675 as a donation from a local company.  When we
    try to read a tape (for instance during a Restore Distribution) we
    get a message that says:

	"There is no magnetic tape hardware on HOST"

    But there *is*.  And it's registered as a service in the host's 
    namespace object.  Anybody have a clue what the message means?

This problem occurs when the tape drive is not responding to the
system's requests.  The cause can range from unplugged cables to poor
power supply connections to a dead tape drive.  

Further, if you boot the system, and it thinks there is no tape drive,
and then you fix the problem:  You must still reset the system to force
it to look for the tape drive again.

Things to check:
1. Open the front door and look up at the rear of the tape drive.  There
   should be large gray ribbon cable and a four-wire harness plugged
   into the rear of the tape drive.  Make sure both connections are
   tight.

2. While you have the front door open, check the machine's cable
   connections:  The small boards in the card cage have a number of
   ribbon cables connected.  Make sure all these cables are connected
   tightly.

3. There is a special 24V power supply for the tape drive mechanism that
   could be turned off.  Open the rear door, check the supply's circuit
   breaker and turn it on if necessary. (The supply should be located
   just below the card cage on the right side as you look in the rear.)

4. When powering up the system, you should be able to hear and see the
   tape drive reset itself.  It will move the head (inside the tape
   slot) up and down while clicking several times.  The tape drive will
   also reset any time the FEP is reset (either by console command or by
   pushing the front panel RESET button).

   If you don't hear the tape drive reseting, it is either not receiving
   power or it is broken and in need of replacement.