|S1:–||Is the main timing contact and is found on the left hand side of the unit.
There are two set’s by the timing wheel and it’s the inner set.|
|S2:–||Is the space and back-space contact,it’s situated at the rear of the unit,
second set from the right.|
|S3:–||Carriage return and line feed contact, rear of the unit, extreme right.|
|S4:–||CR interlock, right hand side toward’s the rear. If CR is operated,
S4 can be seen to move.|
|S5:–||TAB interlock, rear of unit extreme left.|
|S6:–||Right hand side, closes when in upper case.|
|S7:–||Near S6, closes when in lower case.|
Note that all magnet’s must have a diode across them for two reason’s.
1/. To protect the driver transistor’s.
2/. To make the magnet’s release as quickly as possible.
The 5 volt supply for the 74LS00 was provided by the PIO socket on the
NASCOM, so that if a 12 core screened cable is used (i.e. screen = Ov),
there will be ONE spare way.
The print magnet’s, R1 through CK, are underneath on the left, and from
left to right are:–
T2 CK T1 R2A R1 R2 R5
As for the control magnet’s, it’s simply a matter of applying power to
each one in turn and noting the effect. They are situated on the right hand