Schematic Notes - OKIDATA OKIMATE 20 Technical Service Data

SCHEMATIC NOTES
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Chassis
—
ft—
Circuitry not used
in
some versions
Circuitry used
in
some versions
e
See parts
I
i
st
+
Ground
Voltages measured with digital meter.
Waveforms and voltages are taken
from ground,
unless noted otherwise.
Voltages, waveforms and
logic
readings taken
with Printer running
in
Self-Test
mode.
Waveforms taken
with
triggered
scope and
Sweep/Time Switch
in
Calibrate position, scope
input set for DC coupling
on
"0"
reference
voltage waveforms.
Switch to AC input to view
waveforms after DC reference
is
measured
when
necessary. Each waveform
is
7.5cm width with
DC reference voltage
given at
the bottom
line
of
each waveform.
Item numbers
in
rectangles appear
in
the align-
ment/adjustment instructions.
Supply voltage maintained
as
shown at
input.
Controls adjusted
for normal operation.
Terminal identification may
not
be found on
unit.
Capacitors are 50 volts or
less,
noted.
unless
Electrolytic capacitors are 50 volts or
less,
20? unless noted.
Resistors are 1/2W or
less,
%
unless noted.
Value
in C)
used
in
some versions.
Measurements taken with switching
as
follows,
unless noted:
SW2
Darkness set to Maximum Darkness
DIP Switch
SW1:
1,
2, 5,
ON
3, 4,
6
OFF
DIP Switch
SW2:
AI
I
Off
Logic Probe Display
L=Low
H=High
P=Pulse
*=0pen
(No
I
i
ghts
On)
(1)
Probe
indicates High when
Print Head
is
at Home position.
(2)
Probe
indicates High when
Print Head
is
not printing.
(2)
Probe indicates Low when Print Head
is
at
Home position.
(4)
Probe
indicates Low when Print
Head
is
not printing. g
(5)
Probe
indicates Low when
Print Head
isQ
not moving.
D
(6)
Probe indicates pulse while Print Head
isJU
returning to Home position.
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