IBM 1627 Manual page 18

Drum Step ~,
Motor (M4)
Figure 2-5. 1627 Rear View, Circuit Board and Power Supply Removed
9. Lace the motor leads to the wiring harness.
Reassemble the power supply and circuit
board to the main assembly.
10. Connect AC power to the unit and perform
the Operational Checkout listed in Section 1.
Discontinuities in the 45° line drawn, with
the carriage fast run and drum fast run
controls on, indicates that the motor is
skipping steps because of excessive drag.
Loosen the cap screws and rotate the step
motor slightly counterclockwise. If the
operation is excessively noisy or if the pen
overshoots on incremental steps, backlash
is indicated. Loosen the cap screws and
rotate the motor slightly clockwise.
11. When checkout is completed satisfactorily,
make certain the step motor mounting cap
screws are tight, then replace the cover on
the unit.
Carriage Drive Cables (Figure 2-6)
Three cables make up the complete carriage drive
cable system. The one unshielded cable that runs
Carriage Step
Motor (M3)
--- Plotter Circuit Board
between the drive pulley and the rear spring is a
complete subassembly with the copper sleeves at
both ends crimped tightly. The copper sleeves at
the eyelet end of the other two cables are not
crimped so that the eyelets can be removed for
assembly to the carriage.
To properly install the carriage drive cables,
proceed as follows (See Carriage Scale Factor
Recalibration Model 2 only):
1. Remove top cover.
2. Remove the spring that connects the cables
at the rear of the machine.
3. Clip off old cables at carriage and remove
cables.
4. Remove lower carriage rod.
5. Remove cable terminations from inside
the carriage, using long nose pliers.
6. Partly straighten new bare cable at eyelet
end where it is kinked over copper sleeve;
the eyelet will fall off so that the sleeve can
be removed. Do not straighten cable so
completely that the position of the kink is
lost. Mark the position of the kink with a
2.7