Royal Navys historia

The German under the case cover translates:

To Observe!

Observe the manual for the Encryptionmachine (H. Dv. g. 13)

1. To clean the roller contacts, turn all rolls several times backwards and forwards.

2. To clean the key contacts, press all keys down strongly before turning on power several times and let them pop back up while one key remains pressed.

3. While selection of the characters which are visible in the window, observe that the rollers are in the right position.

4. The "fool proof" (literally: unconfusable) double pole plugs are to be inserted into the holes all the way. The front wooden panel is to be closed, since otherwise three lamps could be lit at the same time.

5. If no lamps are lit after pressing a key, check battery, contact springs, connectors at the switch and the switch itself.

6. If one or more lamps do not light up with a key pressed, the corresponding lamps, the contacts underneath them, the cables of the double poled plugs, the plug receptacles including their short circuit panels, the roller contacts, the working contacts underneath the pressed keys and the "resting"(?) contacts underneath the corresponding keys are to be checked and if dirty or oxidized are to be cleaned (see also number 2).

7. Roller axle and roller receptacles are to be kept clean and like any other bearings occasionally slightly oiled with a sap- and acid-free oil. The fixed contacts of the rollers are to be sanded every six to eight weeks with polishing paper and rubbed with a slighlty oily cloth. The key contacts, the lamp contacts, and the short circuit panels are to be kept free of oil.

8. Key selection is done through either digits or letters. To translate the numbers into letters or back use the following table:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z