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port as the main interface port does for the main port.
Normally, the interface circuits convert parallel data to
serial RS-232C format for output only because the port
may be primarily used for connecting a printer. How-
ever, if a KSR printer or another terminal is connected to
the port, the port may be operated bidirectionally (refer
to paragraph 3.15.5).
5.7 DISPLAY GENERATOR.
The display generator contains the character generator,
attribute logic, and video RAM circuits. The character
generator produces a dot pattern used to modulate the
intensity of the screen raster to produce characters. They
attribute logic controls and keep track of the various
video attributes set for screen characters (refer to para-
graph 3.15.8). The video RAM circuits store all charac-
ters written on the screen.
5.8 VIDEO MODULE AND SCREEN.
The video module contains horizontal, vertical, and in-
tensity modulation circuits for producing a television-
type display on the screen. These circuits generate a con-
ventional interlaced raster display. Character signals re-
ceived from the display generator cause intensified dots
to appear at precise intervals on a raster line. These dots,
when combined with other dots on other raster lines
above and/ or below a given line, produce characters.
The screen is a standard video monitor CRT and a P4
phosphor. Its electron beam is driven horizontally in the
conventional manner magnetically using a deflection
yoke and flyback transformer.
5.9 POWER SUPPLY.
The Model 950 contains a single power supply that pro-
vides dc operating voltages to all circuits within the
Model 950. The supply contains two 3AG type fuses that
are user replaceable. A power transformer, mounted sep-
arately, steps down the ac supply voltage to provide the
supply with the required input voltages. The
115
V
/~30V
power select switch (see Figure 2-2) selects between mput
voltage taps on the transformer for 115 Vac or 230 Vac
operation.
SPEAKER
Chapter 6
OPERATOR MAINTENANCE
6.1 INTRODUCTION.
This chapter provides the end user with instructions for
cleaning and inspecting the Model 950 terminal (periodic
maintenance). It also contains procedures for trouble-
shooting minor problems.
6.2 PERIODIC MAINTENANCE.
Periodic maintenance for the Model 950 consists of
cleaning the exterior of the unit and checking the ter-
minal and keyboard cabinets for signs of damage or ex-
cessive wear. The Model 950 should be checked at the
start of each day it will be in use.
6.2.1 Cleaning.
To clean the Model 950 cabinet exterior, proceed as fol-
lows:
CAUTION
To maintain the beauty of the Model 950 cabinet, do not
use solvent-based cleaners or abrasive cleansers for
cleaning.
1. To clean the terminal, use a soft, lint-free cloth
and a commercial detergent (such as 409), to
remove smudges, fingerprints, and other similar
oily dirt.
2. To clean the keyboard of dust, simply vacuum us-
ing a soft brush attachment.
If
the keyboard con-
tains a coffee or soft drink spill, disassemble it (see
Figure 2-1), and clean it with a soft cloth and
water. Dry thoroughly!
6.2.2 Inspection
To check the Model 950 cabinet and keyboard for
damage or excessive wear, proceed as follows:
1. Inspect the keyboard cabinet for cracks or breaks.
Check the bezel on customized units for paint
damage (peeling, cracking, or severe scratches).
2. Check each key for free movement.
3. Check the rubber feet on the bottom of the key-
board assembly (see Figure 6-1) to ensure that they
Figure 6-1
Keyboard Assembly Bottom
6-36
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