The Restoration of Enigma A16878

Restoration of Enigma A16878 – Part 1

(Scroll down for Parts 2 through 9)

May 2018

Over the next year, we will be documenting the restoration of the 3-rotor Enigma machine with serial number A16878. In part 1 we will review the known history of this Enigma machine, evaluate the machine’s external condition, and make an initial assessment of what will be needed for the restoration process.8


1. History

Enigma A16878 was found in 2017 by a man in Antwerp Belgium who came across the machine while cleaning out an old storage shed. There were no other related items located in the shed. The ID tag located in front of the keyboard reads “A” and “16878 / jla / 43”. The presence of this ID tag is very helpful. This tells us that the machine was made in Berlin in 1943 by Heimsoeth und Rinke which was located at Uhlandstr. 136, Berlin-Wilmersdorf. Many surviving Enigma machines either were not issued with an ID tag or the ID tags have been lost to time. As with nearly all surviving Enigma machines, there are no surviving documents to verify where this machine saw service during WWII. This model Enigma, the Enigma I, saw service with the Wehrmacht and Luftwaffe, as well as many branches of the German government. During WWII, Antwerp was an important city because of its deep water port. It was occupied by Germany in May 1940 and liberated by the British 11th Armored Division in September 1944. As mentioned above, we cannot verify that Enigma A16787 saw service in Antwerp during the war.

2. Condition

  • There is no wooden transport case with the machine.
  • One of the four transport case mounting screws is present and screwed into the underside of the machine. The other three mounting screws are missing.
  • The machine is missing the Steckerboard (plugboard).
  • The wire trunks that connect the sockets of the Steckerboard to the electrical circuit of the machine have been intentionally cut. We can only speculate that one reason the Steckerboard may be missing is that the Germans intentionally disabled or destroyed Enigma machines rather then let them be captured by the Allies at the end of the war. We have seen at least one other example of an Enigma machine being intentionally disabled in this manner.
  • There are no Stecker cables present.
  • Based on the amount of corrosion on the machine, one could speculate that the wooden box rotted away from this machine over time.
  • There are no lightbulbs present.
  • There is rust and corrosion on the exterior and interior of the machine on nearly all exposed metal surfaces.
  • There is a thin layer of dirt and dust on the exterior and throughout the interior of the machine.
  • There appear to be dried pine needles inside the Enigma below the rotors.
  • The mechanism to release the rotors is stiff and binding; however, it was possible to remove the rotors from the machine.
  • The “M” key glass is broken, and the “I” key glass has a small fracture.
  • When keys are pressed, there is resistance and the keys do not return to their starting position. The rotors do not advance when a key is pressed.
  • The clips for the rotor cover and contrast screen on the top of the machine are rusted in place and are not able to be moved.
  • Both cover hold-down screws on the top of the machine are bent and one is seized in place.
  • Rotors I, II, and III are present and all are engraved with the same serial number as the machine, A16787. The rotors appear to be original to the machine and in good condition.
  • It is not clear if this machine was located in a high-moisture environment and/or was submerged in water at some point in the past 75 years. If the machine was submerged, it may have been for a relatively short period of time based on the degree of corrosion compared to other water-damaged machines we have seen in the past.

3. Initial Assessment of Restoration Process

  • A thorough disassembly and cleaning of every piece of this machine will be required.1
  • Many parts will require soaking with penetrating oil to access for service.
  • A replacement Steckerboard will have to be assembled, wired, and connected to the machine.
  • Stecker cables will have to be located for this machine.
  • Keyboard keys will need to be repaired.
  • All electrical contacts will have to be cleaned and tested.
  • The rotor contacts will have to be cleaned and tested. Testing will include verification that the wiring of each rotor is consistent with Enigma I rotors.
  • Certain parts will require light lubrication after being cleaned or repaired.
  • An appropriate oak transport case will have to be acquired for this machine.
  • Lightbulbs will have to be placed in the machine.
  • A battery pack will be placed in the machine to allow it to be fully functional.
  • Final testing of all electrical and mechanical elements will be required.
  • Enigma A16878 will be photographed and added to the Enigma Museum archives.

Notes: This assessment may change as the machine is dismantled and the interior is inspected more closely.

Part II will include the removal of the metal top and sides of the Enigma machine so that the interior of the machine can be examined. All screws will have to be pretreated with penetrating oil to ensure that they are not damaged when removed. Disassembly of the machine will begin.

End of Part I

See pictures below. (The last picture is of this Enigma machine’s new home while it is being restored.)





























































































































Restoration of Enigma A16878 – Part 2

June 2018

In Part 2 of the restoration, we will remove the outer metal case from the Enigma machine and inspect the machine for any damage or missing parts not identified in Part 1. Then we will remove the various components from the base of the machine to allow for better access to all parts of the machine for cleaning and repairs as needed. Throughout this process we will be using small amounts of penetrating oil and great care in removing parts so as not to damage screws or other fasteners that may have corroded in place. Only small amounts of penetrating oil are used to avoid damaging the finish of the machine and limiting the chance that oil will contaminate electrical contacts.


  1. Remove metal case and top from the machine. This is done by removing screws from around the base of the machine as well as very small screws located in hinged area of the metal cover in the back of the machine.












With the cover removed, we can see confirmation of our original assessment that there is corrosion on almost all exposed metal parts of the machine. In addition, we see that there is dirt, small glass fragments from broken light bulbs, and a few pine needles scattered around inside the machine. The presence of broken light bulbs is not uncommon on machines that we inspect. However, we have not previously encountered pine needles in an Enigma machine! To keep the “story” of this machine alive, we will save some of the pine needles and other debris from this machine in a clear plastic bag to accompany the machine when it is fully restored.












  1. Remove keyboard assembly. The removal of the keyboard assembly is standard practice for us when cleaning an Enigma machine and restoring it back to working order. The electrical contacts that are activated when the keys are pressed are prone to corrosion and often require cleaning regardless of the overall condition of the machine. In the case of this machine, not only are the key contacts heavily corroded, but so too are the actual key tops and stems. The keys are difficult to press and do not return to their starting position due to this corrosion. The keys will have to be removed from the keyboard assembly and cleaned individually.










  1. Remove the Lamp panel and the keyboard contact assembly. First the lamp panel is removed from the machine. Then screws are removed from under the base plate to allow for the removal of the keyboard contact assembly.













  1. Remove the battery holder. The battery holder is removed to allow access to the nuts that secure the input rotor to the machine.











  1. Remove the input rotor. Extra care is taken any time we work with components containing Bakelite parts such as the input rotor. 75 year old Bakelite is fragile and easily broken.

As previously observed, this Enigma machine is missing the Steckerboard (plugboard). Normally, wires would come out of the keyboard contacts to the Steckerboard and then from the Steckerboard to the input rotor. The whole electrical assembly of the machine would be connected via wire trunks. Locating, assembling, and wiring a Steckerboard will be a later step in this restoration process.

  1. Removal of the stepping bar. The stepping bar is removed to allow nearly full access to the base for a thorough inspection and cleaning.



  1. Apply penetrating oil to corroded clips and fasteners on metal top of Enigma.



End of Part 2.

Part 3 of the restoration process for this Enigma machine will involve cleaning the various components of the machine.



Restoration of Enigma A16878 – Part 3

November 2018

In part 3 of this restoration we will be testing circuits and identifying wires. In addition, we will clean the key contacts, light bulb contacts, rotor advance pawls, and letter film.

  1. The input wheel, or Entrittswalze, had its wires cut, likely when this Enigma machine was intentionally disabled by its operator at the end of the war. Using an electric meter, we test the functionality of the input wheel and identify the 26 wires in the wire bundle. Once identified, the wires are labeled A-Z with colored tabs.








2. All interior and exterior components of Enigma A16878 show signs of exposure to moisture and dust. Corrosion is present on nearly all exposed metal parts. The keyboard contacts need to be quite clean to ensure good functionality of the machine. We sometimes use tamarind paste (an acid) in water as a gentle cleanser to remove rust and corrosion. For cleaning the metal contacts we are using 1200 grit sandpaper. We are not applying a lot of pressure with the sandpaper so as not to damage the contacts. Normally, we would use a less abrasive cleaning medium; however, the corrosion on this machine is extensive.











3. The light bulb contacts on this machine had a coating of dirt and corrosion. With the light bulb socket panel removed we can access the contacts with a brass rotary brush.











4. Once the light bulb and key contacts are cleaned and reassembled, we use a circuit tester to identify and label the wires A-Z. The wire trunk was intentionally cut at some point in the 75-year history of this machine so we are also splicing on additional wire that will be able to reach around the light bulb and keyboard assembly to the plug board on the front of the machine.



5. It appears that Enigma A16878 was stored for a long period of time in a dusty and moist environment without a wooden box, or panzerholz case. One result of this is a significant buildup of dust and dirt on the letter film. We used a solution of warm water with a small amount of dish detergent for cleaning.












6. On many of the Enigma machines we service, the springs holding back the stepping pawls are corroded and fail to press the pawls against the rotors. This results in the rotors failing to advance with key presses. We have found that in most cases the springs either rust and/or the lubrication oil has become firm with age. The fix for the springs is a combination of lubricating oil and moving the pawls manually to work the oil into the mechanism. In severe cases, a soldering iron can be held to the spring to assist the effectiveness of the penetrating oil. Caution should be taken not to get excess oil spread throughout the machine. The oil can cause rotor connections and other electrical contacts to become nonfunctional.












End of Part 3

Parts 4 and 5 will likely include the dismantling and cleaning of the keyboard and the construction of a plug board or Steckerbrett from replica and original parts. The Steckerbrett was intentionally removed from this Enigma and no longer is present.



Restoration of Enigma A16878 – Part 4

March 2019

(The winters in Vermont, where Enigma Museum is located, are long. This project was helpful in keeping us occupied during the cold days of January and February. . .)

In part 4 of the restoration of Enigma machine A16878, we will be creating a replacement plug board (Steckerbrett) for the front of the machine. When Enigma A16878 was acquired by Enigma Museum it was missing the plug board. It had been intentionally removed from the machine and the two wire trunks leading from the plug board to the keyboard and the input wheel (Entrittswalze) were cut. First we will locate a plug board panel. Second we will acquire the hardware and electrical contacts needed to assemble the plug board. Third we will assemble the plug board and connect the wire trunks from the plug board to the keyboard and the input wheel. Finally, we will secure the wire trunks with a wrapping of fabric as was done when the machine was originally manufactured in Berlin in 1943.


  1. Identify a viable replacement plug board panel. We had two choices for consideration as replacement panels. One was a very fine, exact replica plug board panel made by Jim Oram in North Carolina. The other plug board was on a relic battlefield-found original Enigma machine that has extensive corrosion and, as such, is not a candidate for restoration.

Exact replica plug board made by Jim Oram

Relic, badly corroded Enigma machine recovered from a battlefield in Europe
















Relic Enigma machine

Relic Enigma machine















Enigma Museum does not manufacture any replica parts, and we strive to use original parts in our restoration projects whenever possible. In this case, we chose to attempt to use the relic battlefield-found plug board knowing that it could break or fail at any time as we tried to remove it from the front of the relic Enigma machine as well as when we tried to remove the corroded plug sockets and related hardware. The material from which the plug board is made, becomes very brittle with age. We carefully ground off the heads of the mounting screws on the front of the Enigma (they were too corroded to be unscrewed) and carefully pulled the plug board from the machine. The wires from the plug board had completely corroded away, so the plug board became free of the machine once the corrosion “released” it after some gentle prying and wiggling.


















2. Salvage hardware from relic plug board and acquire spare parts as needed:  Once extricated from the Enigma machine, we carefully removed all of the plug sockets and related hardware. This first required using a wire brush and other tools to remove corrosion so that nuts could be accessed with appropriate wrenches and tools. The process of removing the plug sockets and hardware was slow. Care was taken to not break the plug board and, once removed, each piece of hardware was cleaned with a wire brush and sand paper.
































Once all hardware was removed from the plug board, the plug board was cleaned and then a hot clothes iron was used to slowly heat and press the plug board flat. The plug board had become warped as corrosion on the Enigma machine expanded and pressed against the plug board over time. Though not perfectly flat, the ironing did create a usable surface so that we could proceed.


3. Reassemble hardware back onto plug board. A decision was made to use vintage coated wire from the 1960s. The original wiring on most Enigma machines is cloth coated. The cloth coated wire available to us was too brittle and would have been susceptible to damage in the restoration process. None of the springs that hold the shorting bars down on the plug sockets were able to be salvaged. In addition, four of the shorting bars were too corroded to be functional. For these parts, exact replica parts were used.
















































4. Finally, once all hardware and wires are attached, we secured the wire trunks leading to the keyboard and the input rotor with a wrapping of fabric.




























The restored plug board








Image of fabric wrapped wire trunks on an original Enigma machine




End of Part 4.

Part 5 will include the disassembly and cleaning of the keys from the keyboard.



Restoration of Enigma A16878 – Part 5

March 2019

In Part 5 of the restoration of Enigma A16878 we will disassemble, clean, repair, and reassemble the keyboard. This Enigma machine was likely exposed to high humidity, dirt, and other environmental elements that have created systemic corrosion over the last 75 years. Corrosion and dirt in the keyboard assembly has made it so the keys do not press down fully or, when some are pressed down, they do not return to the full up position. With keys in this condition, the machine would not be operational as full motion of the keys is required to advance the rotors with each key press. In addition, the dirt has bonded with existing lubricants as well as the penetrating oils we have applied to prepare this 75 year old antique for disassembly. If not thoroughly cleaned, this oil and dirt would ultimately cause electrical contacts to fail in this machine. We will also be repairing the broken glass top of the “M” key.

It should be noted that this restoration project is not an attempt to make Enigma A16878 look like new. In all of our restoration and repair work, we strive to use original parts and preserve original patinas. These rare and historic antiques are more than 70 years old and all of them have taken on a certain look based on how and where they were used during WWII and how and where they have resided since May of 1945.


  1. Images of the keyboard when we received Enigma A16878 from Europe.
























2. Disassembly of the keyboard. Care is taken in removing the various components of each key. Penetrating oil was applied to parts of this keyboard months before attempting to disassemble it. These components are very specialized and it is extremely difficult to find original replacement parts.





































3. As parts are removed, they are cleaned of corrosion, dirt, and oil. The keyboard itself is wiped down with a clean cotton cloth with care taken not to damage the textured finish.




































4. Repairing the broken glass top on the “M” key. For this repair we used parts from another relic Enigma keyboard. This relic keyboard is too corroded to be a good candidate for restoration so we are using it for its original parts. Some of the glass tops to the keys on this relic keyboard are not broken. Using a very fine grinder, we remove a little of the bottom of the metal ring that secures the glass in place. Then the metal ring is slid off of the top of the key allowing us to access the round glass top. The glass top is then put onto the “M” key from Enigma A16878 and its metal ring is gently slid back onto the key and crimped into place.


Relic keyboard to be used for parts

Some glass tops on the relic keyboard are intact
















Disassembled key top

Preparing to replace broken glass on “M” key















“M” key with glass replaced






4. Reassembly of the Keyboard. With all key stems, screws, springs and retaining plates cleaned of oil and dirt, the parts are reassembled onto the keyboard base.










































End of Part 5.

Part 6 will involve checking the functionality of the rotors and repairing and/or cleaning them as needed.


Restoration of Enigma A16878 – Part 6

April 2019

In part 6 of the restoration of Enigma A16878 we will be checking the integrity of the rotors and reflector and verifying the wiring.

One very nice feature of Enigma A16878 is the selection of rotors that accompanies the machine. This Enigma was found in a shed in Belgium with rotors I, II, and III all with serial numbers that match that of the machine, A16878. In addition, the reflector (UKW) is also engraved with the serial number A16878. Enigma machines are often found with rotors that do not have matching serial numbers as the rotors are interchangeable between machines. Enigma machines were often used in groups at command centers, etc. Operators could use any rotor in their machine regardless of the serial number on the rotor.

In addition to having serial numbers that match that of the machine, these rotors have Bakelite thumb wheels instead of metal thumb wheels. The use of Bakelite rotors began as the war turned against Germany and metal supplies dwindled.

Despite the obvious corrosion and damage to this Enigma machine caused by exposure to moister and dirt, the rotors appear to be in very fine condition. This may, in part, be a result of the rotors being mounted in the machine (suspended above the base plate of the machine) with the metal Enigma cover closed. This would have resulted in the protection of the rotors from direct contact with water, etc.

Below are pictures of the rotors and the reflector.























  1. The electrical contacts of the rotors are cleaned. Sometimes simply rubbing the contacts with a cloth is sufficient to clean the brass contacts on either side of a rotor. If needed, a very fine sandpaper (2000 grit) can be used.












Despite being manufactured toward the end of the war, these rotors appear to have seen a great deal of use. Note the grooves formed on the flat back contacts of the rotor from having the contacts of an adjacent rotor rubbed against them with each keystroke of the machine.






2. Once the contacts are cleaned, a check of the continuity of each contact is made. A metal plate makes contact with the spring loaded contacts on the front of the rotor while an electrical probe is used to make contact with each flat brass contact on the back of the rotor. The internal wiring of Enigma rotors is fragile. The wires are very thin and the soldered connections inside the rotor are susceptible to failure with exposure to moisture, movement, etc.



3. Once the contacts of the rotor are confirmed to be functional, individual contacts are tested to verify the wiring configuration. Some Enigma machines that survived the war were used by countries post-war. These countries did not know that the Allies had broken the Enigma codes at Bletchley Park and elsewhere. These countries would sometimes rewire the rotors to a unique configuration to better the encryption of their secret messages. We will be checking to verify that these rotors are wired as they would have been when issued to the German military.

A wiring chart that shows the standard wiring of Enigma rotors is used. This chart was developed by Dr. David Hamer. A very detailed description of Enigma rotor wiring can be found at






In the case of these three rotors as well as the reflector, all were found to be wired as the German military would have received them when this machine was put into service in 1943. In addition, all contacts were verified to be working and in good order.




Part 7 will involve general cleaning and restoration of the metal Enigma top.



Restoration of Enigma A16878 – Part 7

May 2019

In Part 7 of the restoration of Enigma A16878 we will repair and clean the metal top and metal base of this cipher machine. Our goal in this segment is to clean the dust and dirt from the metal top and base and to salvage the various fasteners on the metal top that are badly rusted and seized in place.

As discussed in the introduction to this restoration project, this Enigma machine was exposed to high levels of moisture as well as some blunt force trauma. The metal top of the Enigma machine has some rust, bent and seized hold down screws, as well as seized hold down clips. Fortunately, we knew this project would likely take a year to complete so we knew we had time to patiently apply small amounts of penetrating oil to the seized fasteners on the metal top. Care was taken not to saturate the top with oils to avoid unnecessary damage to the original black paint.

In a previous segment of this restoration process the letter film had been removed and cleaned separately.

Here are a few pictures of the metal top of this Enigma machine when it was received by Enigma Museum in 2017. Note the dirt, rust, and bent components.























  1. Remove the metal hold down screws, other fasteners, and the rotor cover from the metal top. Extreme care was used to not apply too much force in this process. The application of penetrating oils over the last 12 months made removing these fasteners possible.  These pictures show the metal top after 12 months of applying penetrating oils.









































Note the arrows pointing to the serial number of the machine stamped into the metal hinge.


Removing fasteners from the metal top. Each fastener is dismantled and each component is brushed to remove rust and corrosion.

















The hold down screws were carefully bent back into shape























The base of the Enigma machine is also prepared for cleaning with all major components removed.






With fasteners removed from the metal top and the base prepared, both pieces are washed in very hot water with a mild soap. The hot water allows for the pieces to dry quickly after their brief wash with the soap.








With the metal top cleaned, fasteners, the rotor cover, and the letter film are remounted.


























Finally, all of the components are back in place on the metal top. Our cleaning efforts were mostly successful. Some of the results of prolonged exposure to moisture are still evident. However, our concern was to clean and stabilize the finish of the machine. We were able to do this without sacrificing any of the original parts or finish.












End of Part 7.


Restoration of Enigma A16878 – Part 8

May 2019

In part 8 we will reassemble Enigma A16878 with all of the cleaned and restored components.

At this point in the restoration, we have cleaned and restored all of the internal components of the machine as well as the exterior metal case and metal top. In addition, we have tested and cleaned all electrical contacts as well as the contacts on the rotors, reflector, and input wheel.

  1. All of the components of Enigma A16878 ready to be reassembled.





2. The stepping bar is mounted to the base and confirmed to move easily in its mounts. The input wheel is remounted and the battery box is put into place.










3. The lamp panel and keyboard switch assembly is mounted in the middle of the base. Care is taken to place the wire trunks leading to the plugboard so that they do not interfere with the motion of the stepping bar.













4. The keyboard assembly is positioned in front of the keyboard contacts and slid back onto the front of the machine.











5. The plugboard is secured to the front of the machine and rotors and reflector are placed into the machine.












6. Light bulbs are placed in the machine and an external power source is connected to the machine. A key is pressed AND………



We are very happy to report the very first key press of the restored Enigma A16878 resulted in the lighting of a light bulb! (We were very happy with this result!)


Here are a few pictures of the reassembled machine.























End of Part 8.


Restoration of Enigma A16878 – Part 9

July 2019

In Part 9 we will prepare an oak transport case for Enigma A16878 and finish the restoration by mounting the Enigma into the case and adding Stecker cables to the plug board.

In early 2019, Enigma Museum was contacted by the Granddaughter of an American Serviceman who served in Europe during WWII. She mentioned that while he served overseas he had sent home some things from Germany in what appeared to be an Enigma wooden box. She shared pictures of the box and information regarding her Grandfather with us and we agreed to purchase the box.

Her Grandfather was Sargent Charles McNeill. Sargent McNeill’s discharge papers (dated 12/31/45) show that he was a mechanic in the 101st Airborne Division. He joined the military in June 1943 and served in Africa, the Middle East, and Europe. He was involved in campaigns in Normandy, the Ardennes, the Rhineland, and Central Europe. In a letter to his parents just days after the end of the war (see below) he describes working on Hitler’s limousine in Berchtesgaden. This car is now located at the Auto & Technik Museum in Sinsheim, Germany (see picture). At some point during his time in Europe, Sargent McNeill sent home some things from the war in an Enigma transport case. We are thankful for that as it is now the case for Enigma A16878.

Upon purchase the oak transport case was missing the Zur Beachtung plate and the green contrast screen. An exact replica Zur Beachtung plate and contrast screen were added to the inside of the transport case to achieve the appearance of the case as it would have been when issued to the German military in 1943. The finish on the case was preserved so as to keep the home address of Sargent McNeill which he wrote into the top of the case with a pencil.













Sgt McNeill’s return address. Note the painted “Enigma” in the corner of the box.



Most Enigma boxes do not have the word “Enigma” painted onto the wood. This box has “Enigma” painted above the leather handle and on the top corner of the box. (See other picture)

Waffenamt (manufacturer’s code) stamped inside the wooden box.















A picture Sgt. McNeill took of the limousine described in the letter above.



The limousine as it looks in 2019 at the Auto & Technik Museum in Sinsheim, Germany.



Enigma A16878 in Sgt. McNeill’s wooden box.


Exact replica extra Stecker holders, Zur Beachtung sign, and contrast screen mounted into the top of the box.



With Enigma A16878 mounted into the oak transport case and a set of original Stecker cables mounted into the machine, this project is complete. This machine will be photographed and the pictures added to our collection of images which we have been accumulating for more than 30 years. The machine will be in our collection for a period of time and then likely offered for sale. Enigma museum provides Enigma machines to private collectors, auction houses, and museums. We have customers around the world including Bletchley Park, the NSA’s National Cryptologic Museum, the Deutsches Museum, the Harry S. Truman Library and Museum, the University of Brazil, and the International Museum of World War II.


We hope you have enjoyed this report on the restoration of Enigma A16878.


© Enigma Museum 2019