Page 7: One or More Key Switches Doesn’t Operate

If one or two key switches do not operate but all the rest do, you may just have some broken switches. However, we have seen situations where, for example, the first three key switches work, but none of the rest. This may also be due to broken buss wires (the wires that carry current to all of the switches).

Visually inspect each key switch. Make sure they are held onto the key drum with the silver knurled nut. If the nut is missing, the key switch is probably broken. The key switch has a threaded neck, onto which the knurled nut on the outside of the key drum is screwed.

Next, remove the key drum and access hole cover. Check to see that the buss wires – 300KSWIRE (Ref. E501BW) – are not broken (there is one on each side of the key switches). For example, if the 6″, 9″, and 12″ switches operate, but none past 12″, the wire(s) may be broken just at or past the 12″ switch.

A. Replacing Broken Key Switches

See Subject 3: “Feeds Longer Strips of Tape”, Section B. III

B. Replacing Broken Buss Wires

There is no easy way to replace a broken buss wire. The fastest way we have found:

  1. Unplug the machine.
  2. Loosen all of the small screws that hold the key switches to the buss wire.
  3. Slide out the old, broken buss wire.
  4. Carefully thread the new buss wire under each loosed screw. It takes patience.
  5. Make sure that the new buss wire does not thread under the key switch. If this happens, that key switch will not work.

Caution: The buss wire carries current. If the buss wire touches any other metal under the key drum (other than the key switches only), the operator could get a shock. CAREFULLY check the new buss wire after installation. Is it touching any other screw, nut, or other metal piece inside the key drum? If so, make sure the buss wire is repositioned so that it does not make contact with any other component besides the key switches.

If you have any questions about any of the above procedures, please feel free to call us at 1-800-899-9389.

Tigerseal Products Sales and Service
13093 Old Ridge Road
Beaverdam, VA 23015