The US 6812 Division Bombe Report Eastcote 1944 Page 57

Tony Sale's Codes and Ciphers

| previous page | next page | index page |

- 46 - TOP SECRET-T

SETTING UP MENU ON BOMBE.

Together with his checker the operator plugs up his menu and sets his

wheels. There are 10 distinct steps in setting up and putting the bombe in
operation. They are:

(1.) Plug up the bombe,

(a.) Plug the enigmas to the commons.
(b.) Patch the commons to the diagonal board.
(c.) Count the letters plugged on the diagonal board and

compare this count with the menu.

(d.) Count the number of plugs in the commons. There should

never be less than 3. Compare this result between banks.

(e.) Compare the commoning jack positions in enigmas between

banks.

{2.} Attach the enigma wheels in proper order from top to bottom.
(3.) Set the enigma wheels in the proper position from top to bottom.
(4.) Check the entire bombe for

(a.) Loose plugs.
(b.) Wrong settings.
(c.) Clips in place.

(5.) Operate one Searching switch for each of the chains in use:

(a.) Carry switch should be OFF.
(b.) Carry Home switch should be OFF.
(c.) Delayed CB switch should be OFF.
(d.) Check input board for correct input (Single or Double).

(6.) Operate Motor and Control switches.

(a.) Motor switch is at left as you face the bombe.
(b.) Control switch is at right as you face the bombe.

(7.) Depress Start key.

(a.) Start key is at right, Stop at left.

(8.) Operate Carry switch when bombe has attained its normal speed of
64 rpm (top drum).
(9.) Observe the clock and enter on the Job Sheet the time the run
started.
(10.) Check the Job Sheet for all entries,


ENTRIES ON JOB SHEET.

At the top of the Operator's Job Sheet put down the name of the

machine, the name and date of the menu, the job number, the number and type
of the menu, and whether or not reruns are to be made in case of trouble.
The following information is entered in the body of the sheet ,-RUN NO.,
TIME STARTED (including signature of the operator),WHEEL ORDER ,STOPS
,RELAY, and REMARKS. The last 4 entries are repeated for each bank. In the
REMARKS column the number of the stop is shown in circle, the link removed
in case of a "check stop", and either a check mark or cross to indicate
that the checker has found the stop to be either good or bad.
A typical job sheet made out for the menu of fig. 39 is shown in fig. 41.

PREPARATION OF CHECK SHEET.

When the bombe seems to be running satisfactorily and the operator is

making out his Job Sheet, the checker should fill out his Check Sheet. The
alphabet should be written across the top of the sheet. Letters on the main
and auxiliary chains should be circled. Put a tadpole (wavy line) below the
letters on the subsidiary chain. Letters on phantom links should be
indicated by a half circle above or below the letter. Fill in the details
called for at the top of the sheet,-TITLE (Menu title and date of
intercept), MACHINE, MENU (number) ,JOB (number) and the type of menu and
whether or not the job is to be rerun in case of trouble. Write down the
letters of the menu in the narrow column at the left end of the sheet,
starting with the input letter and following consecutively around the
menu so as to check through closures first. See typical check sheet made
out for


---




| previous page | next page | index page |