Subaru 1600 Service Manual page 710

ELECTRICAL SYSTEM
• Speedometer
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Specifications
- - .
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Range of indication
0 to 140 km/h or 0 to 8 5 MPH (Speed over
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140 km/h or 85 MPH is in dicated as 140 km/h
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~MPH)
i-R~S~i~ing ~;wer-;;-f----
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1 km/h or 1 MPH
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indication
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-----------._----
swing over 60 km/h)
!-------------------=--------------------------
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Cycle of indication 0.5 ± 0.05 second
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--------
- - - - - - - - - - - - -
~
Accuracy of indication ± 2 km/h (3 krn/h including
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Hvsteresis of indication 1 km/h or 1 MPH or less
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Input signal 637.5 rpm of speedomete r cable at 60 km/h,
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~
_______________
~----
: 1,035 rpm of speedomete
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6 pulses/rev.
r cable at 60 MPH
voltage: IV, max.,
km/h (12 MPH), 50±
!
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VB voltage: 5V, min., VL
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Duty radio: 50±30% at 20
, 10%at 100km/h (62 MPH )
f------------
!
Speed warning device
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figures of car speed Bar lights (Red) under the
come on at 88 km/h or 55 MPH or over.
--
2-1/2 digit)
ri:li~;~~kmen~-----
Fluorescent
di~~~(
- - -
Speedometer
cable
Car-speed
Wavefonn
~ensor
modification
revolutions
3) Indicant standards
Standard car speed (MPH) 10 29.75 50.5 70.25 85
2) Operation
The revolutions of the speedometer
cable are transmitted to the speed
sensor, and pulse Signals corresponding
to the car speed are produced by the
photo coupler.
The car-speed pulse signals are modi-
fied in wavefonn, are counted by the
counter circuit, and memorized in the
memory circuit. The memorized data
is sent to the display circuit every
0.5 second, and the car speed is
indicated with the fluorescent display
tubes. (The above processing is per-
fonned by a microcomputer.)
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Microcompu ter
1
!
Indication drive
circuit
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Fluorescent
display tube
Tolerable indication error
Indication (Indicator displays only
up to 85 MPH.)
(MPH)
12 ± 2
Standard car speed (km/h) 25.5
Tolerable indication error
(km/h)
29 ± 2
NOTE:
The car-speed sensor circuit and the
speedometer cable coupler are united
32 ± 2 53 ± 2 73 ± 2 is only
confirmed
50 75.5 100 125.5
54 ± 2
80 ± 2 I05±2
131 ± 2
in a body on the back of the speed-
ometer display unit. The car-speed
sensor circuit must never be dis-
15-47
140
Indication
is only
confinned
(Indicator displays only
up to 140 km/h.)
assembled. Doing so causes an adverse
effect on the detection performance.