Having cleared the trouble, the technician instructs the operator to make
the run over again and if there is no good stop on the run in addition to
the wrong stop then a check stop shall be taken in order to fulfil the
requirement of getting one good stop per wheel order.
TAKING A CHECK STOP.
A check stop is taken when the slow drum is halfway round and a
good stop has not been recorded on each bank. The procedure for taking a
check stop is as follows:
1. Turn OFF the Carry Switch.
2. Press the Stop key. The bombe slows down and stops.
3. Turn OFF the Two main power switches and remove the top drum of
the selected link. Break a female or the smallest closure. If
there is no closure, an outlying link may be taken off. In any
case the link being broken must be one or more links removed from
4. Having removed the drum, turn on the TWO main power switches,
press the Start Key, and as soon as the bombe speeds up, Operate
the Carry Switch.
3. The menu is now weakened and the bombe will stop. When it does
shut off first the Carry and then the main power switches. Write
down the stop in the usual manner. Replace the removed drum and
verify that it has been put back on its correct setting.
6. With the Carry Switch OFF, turn on the two main power switches
and start the bombe again by first pressing the Start Key and then
lifting the Bail Lever.
7. If the stop comes in again, it is a good stop. If not a notation
is placed in the Remarks column of the Operator's Job sheet and on
the Stop Slip stating what link was broken.
8. At the end of each run (coming back to ZZZ) check the settings for
any shifting during the run. If any shifting is found, call a
STRIPPING THE BOMBE.
Whenever notification is received that a job "up" at some point all
bombes working on that job are stripped immediately. Also when a bombe has
finished its allotted runs, it is immediately stripped provided the menu is
not designated as "Do Not Strip". Turn off the two main power switches, the
two Carry Switches, and the Searching and Chain Switches. The Input switch
should be thrown to the Single input position because the probability is
that the next menu will be of the single input type. One end of each record
is unplugged, removing the end that is not plugged into an enigma or a
SHORT TESTING THE BOMBE.
Each bombe is short tested after each job. The operator strips the
machine as described above and plugs it for "short test". To plug the
machine for "short test the operator selects six cords and plugs four of
them one each into each of the "commons" and the other two one each into
the CSKO and SSS jacks. The bombe is then tested by the technician for
short circuits using the "trolley". This testing circuit is arranged to
test each lead against all the other leads for the possibility of a short
with any other lead. When the test is satisfactorily completed, the cords
are removed from the "commons" and the CSKO, and SSS jacks. Those ends of
in the enigmas and "commoning" jacks are not disturbed.
CHANGE OF WATCH AND NOON RELIEF.
The operators must not leave the bombes at the end of a shift until
the relief operator has been thoroughly informed of the status of the job
being run, plus any peculiarities or defects of the bombe. This includes a
check of the searching and chain switches by the relief operator prior to
taking over. The operator will keep an accurate log book and must be up to
date at the end of the shift. An operator must never leave the machine
while in operation unless properly relieved.