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The Junker DBGM Key

Detail Photos

Many of the surplus Junker keys that we have seen are fitted with a cable and Hirschmann plug.  For details of the plug wiring, click here.

This is what the Junker looks like "under the hood".  The key itself has been removed from the plastic sub-base and the metal base plate. Note the spring tension mechanism and the hand wound and tied coil for RFI suppression.
 


 

This is the famous "click-stop" tension adjustment mechansim and rear contact assembly.  Note how precisely the contacts meet.

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Naming of parts.  This is what the bottom of the plastic sub-base looks like after the metal base plate has been removed.  Screws that hold the assembled key on the metal base are at A.  B indicates the four screws that hold the key itself onto the plastic base.  G is the front contact.  F is the coil RF choke which is in series between the "hot" connection (bottom E) and the front contact.  Some keys have capacitors as well.  The middle E connection is for the common or ground connection, and the screw goes into the metal base of the key proper.  The upper E connection is for the rear contact, and is not connected in this example.  It would be wired to the pin at the base of the rear contact (next to the middle E connection).  C is the mechanism for raising and lowering the platform under the tension spring visible under the lever at D.
 

There is a fiber "washer" pad beteween the plastic sub-base and the metal base.  Thus the entire key is electrically insulated from the metal enclosure.  The mounting screw positions are shown at A.  C is a cable clamp to hold the cord in position after the connections are made (see below), and B is a spring clip to hold the cover shut.


 

This is the rear of the key showing the wire clamp terminals.  Connection 2 is common or ground, connection 1 is hot or front contact, and connection 3 is for the rear contact (often this terminal is not connected internally-- look for continuity between terminal 1and the lower part of the rear contact).  In all cases the screw on the upper surface (recessed) is loosened, the wire is inserted into the hole in the brass termal, then the screw is tightened to clamp the wire in position. 


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