If you have a Digital Data Drive that runs a tape all the way to the end, then starts making a clunking noise, without loading a program, you should check to see if the Digital Data Drive has rubber on the pinch roller. The problem can be that the rubber outer wheel is gone but the aluminum hub is still present and spin able.

Open the door to the drive, you will see the magnetic read/write head as a shiny silver block on the bottom in the dead center. To the right of that will either be a black rubber wheel, or a shiny silver wheel. If the wheel is silver, than the rubber is gone and that's what causing your problem. If the rubber wheel is intact, use your finger to verify that the pinch roller spins smoothly and very freely for several rotations. If it doesn't spin then maybe a portion of the missing rubber wheel is stuck inside the encoder assembly. Once you take it apart, you should be able to tell for sure. The other possibility is that the shaft is out of one of its sockets, or damaged.

On a standard audio cassette deck this pinch roller is nothing more than a spinning wheel which the tape rides on. In the ADAM Digital Data Drives, this wheel is actually an Index wheel with an encoder within the housing that counts how far the DDP has turned to control where the tape starts and stops. So if there is no rubber wheel present for the moving tape to make contact with, which in turn would spin the encoder disc, the ADAM has no idea how far the tape has wound and that's why it runs to the end.


Measured the ID and OD of the rubber wheel on one of your good drives to get the correct size for a replacement rubber roller.
Here are some measurements already done.

Dimensions of Tubing
3/8" (diameter of the aluminum wheel)
1/2" (diameter of the rubber wheel)

Dimensions Metric
10mm (diameter of the aluminum wheel)
13mm (3/8") (diameter of the rubber wheel)


-At a Hardware store, goto the Gas and/or Water Plumbing section to find replacement tubing. You'll want a high temperature firm tubing, like Viton, a high performance synthetic rubber

-Slice a bit off, 11/64" in length.

-Take apart your tape drive from the back.

-First the rear case (cord grip, and 4 screws).

-Then the outer RF shield and printed circuit boards (3-4 screws) and inner RF shield.

-On the bottom inside of the drive below the motors is a small square cover with 2 screws. Remove the screws, gently lift the cover slightly, and slide out the opto sensor (has 4 wires going into it).

-With the opto sensor pulled out, take the square cover off. Be cautious as there are 2 real small parts in here. One is a very small bushing (looks like a tiny silver washer), the other is a small axle (looks like a very small pin) that the encoder shaft spins on.

-Pull the encoder shaft and be careful with the encoder's disc. It is attached to the shaft, but is very thin and fairly delicate.

-Put 2-4 small drops of super glue onto the hub and slide the rubber tubing onto it so that the rear face is flush with the rear face of the hub.

-Once the glue is set and dry with no fumes, trim the front of the rubber if it sticks out farther than the front of the hub, by using a razor blade flat against the hub's face.

-Re-assemble in the reverse order, minding the wiring routing so none get pinched and test it out.