IBM 1627 Manual page 13

Power and Signal Requirements
1.
1627 AC voltage:
115 v AC
1627 DC bias voltage:
Low High Notes
2.
+3 v +2.5 v
+3.3 v
+L,
5 v
+ 1. 25 v + 1. 75 v
-7.5 v
-6.1 v -7.8 v
-9.0 v
-7.3 v -9.0 v
Must be -1. 2 v or more
below -7. 5 setting
-24.0 v -18.0 v
-24.0 v Load 10 vac p. p. ripple
No Load 4 vac p. p.
ripple
3. 1627 input signal voltage:
Minimum up level + 5.6 v
Minimum down level + O. 2 v
Miscellaneous
Environmental Operating Conditions
1. Temperature
2. Relative Humidity
60° F to 90° F
20% to 80%
Operating Speeds
1. Drum and/or carriage motion for the 1627
Model 1 are rated at a maximum of 300
steps per second (200 steps/sec on the 1627
Model 2).
2. Pen up and down motions for both models are
rated at a maximum of 10 operations per
second.
SCHEDULED MAINTENANCE
Scheduled maintenance of the 1627 is limited to
periodic cleaning and operational checkout. No lub-
rication is required. A small amount of IBM #20
grease can be used on the threaded portion of the pen
carriage to facilitate removal and installation of the
pen assembly. Use caution to prevent any lubricant
from getting on the electrical spring contacts in the
key slots on the carriage.
Because the Operational Checkout described in
Section 1 is normally performed at the start of each
recording run, this portion of the maintenance
schedule may be omitted if the instrument is fre-
quently used. If the plotter is used infrequently, it
is recommended that an operational checkout be per-
formed at least once a week.
The carriage rods, the drum surface, and the
metal plunger inside the pen assembly should be
cleaned periodically. The intervals at which clean-
2.2
ing should be performed are determined by the op-
erating environment and the frequency of use. All
normal cleaning can be accomplished with a soft,
dry cloth. If necessary, the cloth can be moistened
with IBM cleaning solvent to remove foreign matter.
The inside of the pen assembly plunger (Figure 2-1)
is cleaned by pushing one corner of the cloth through
the center. If the plunger is clogged, it can be
dipped in cleaning solvent and then wiped dry.
NOTE: Customers should be informed that ball-
point pens characteristically accumulate ink at the
tip. The pen should be removed and cleaned about
every hour of operation. Pen life is approximately
5
to
7
hours. Pen replacement should be considered
before critical drawings are made to reduce the
possibility of smear.
I
CAUTION: Use care to avoid damage to the insu-
lation on the carriage drive cable. This cable
supplies -24 volt power to the pen solenoid.
SERVICE INFORMATION
Isolation of 1627 Troubles
Most troubles can be quickly isolated to the using
system, or 1627 using standard diagnostic proce-
dures. Troubles occurring in the 1627 can be
quickly isolated to one functional circuit by perform-
ing the Operational Checkout described in Section 1.
Following this, the trouble can be isolated to a single
component by performing systematic checks of volt-
ages and waveforms at the test points shown on the
circuit diagrams ill Section 3. Waveforms illustrated
on the circuit can be obtained by using the Manual
Fast Run controls on the 1627 as previously described.
The waveforms shown for the pen control circuits can
be obtained by programming the using system to per-
form alternate pen up and pen down motions. A
guide to trouble analysis is given in Table 2.
CAUTION: Use extreme care when performing
tests on the plotter with power on and the cover
removed. Accidental short circuits between ter-
minals on the printed circuit board can burn out
a diode or transistor. Use care also to avoid
shorting the carriage drive cable or its idler
pulley to the chassis. When power is on, -24 volts
DC is present on the cable and the pulley.
Circuit Board Component Measurements
After a trouble has been located to a specific stage,
by performing systematic checks of voltages and