80-Bus News


March-April 1983, Volume 2, Issue 2

Page 8 of 55

sl s2 $3 Sh $5 741800 N/O t J | } J J Ov ——e—___ TF ry ry N/C t { t BUSY line. port 4 bit l. Fastest Slowest Changeover. 74L,$00 Changeover. S6 Ov > S7 HYFT line, port 4 bit 0. +50 Volts. \ Z y 0.7A Max. + c c c > Pr (each magnet | | | | | | | requires 100mA) . R1 Re Yt R5 “t a SP T2 “| y UG 16.145 14 13 12 i 10 L 3 R.S. Darlington Driver I.C. 307=109 1 2 3 4 5 6 7 \—ov. BO Bl B2 B3 B4 B5 B6 B7

ou T PUT P OR T 5.

Sl:-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,

$3:-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,

SSt-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, Rl through CK, are underneath on the left, and from left to right are:--

T2 CK Ti R2A Rl 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 side, underneath,

This is an OCR’d version of the scanned page and likely contains recognition errors.

Page 8 of 55