Sharp R-9570 Service Manual page 21

Rig570
RELAY CIRCUIT
While the unit is cooking a "L" level signal is produced at RO
relay (RY I).
terminal of LSI and also a pulse signal at Rl terminal of LSI.
The "L" level signal from RO terminal is applied to Q82 which
The pulse signal from RI terminal is applied to the rectifier cir-
is connected in series with Q81 and current i2 is made only
cuit made up of D80 and D81 where it is made into DC signal
when both Q82 and 081 are turned on allowing the cook re-
to charge C81. With C8l charged, 080 and 081 turn on in
succession so that a current il is made to turn on the control
lay (RY2) to turn on.
Figure T- 14.
INDICATOR CIRCUIT
E6,E7 and E9- El9 lo-K,lJB and LB)
EO- E5
Method of Display
Indicator element is Fluorescent Display.
Basically, a Fluorescent Display is a triode having a cathode,
a grid and an anode. Usually, the cathode of Fluorescent Dis-
play is directly heated and the filament serves as cathode.
When a proper voltage is applied to the filament to heat it,
thermo-electrons are emitted and, with positive voltage with
respect to filament being applied to the anode and grid, elec-
trons hit against the anode to illuminate the fluorescent body.
If the anode or grid voltage is zero or negative against the fila-
ment, thermo-electrons can not reach the anode, hence the
fluorescent body is not luminescent.
In this model, the Fluorescent Display 6-digits, 13 segments
are used for displaying figures.
The Fluorescent Display employs the dynamic drive method,
when the high level of anode signal and grid signal agree, the
corresponding segment displays.
The following signals are responsible specifying segments.
Figure T- 15.
Ftlament
Segment
Character format
Signal Segment
a El9 COMPU
b
El8 MED.
s
El7 LOW
El6
f/$-/b e $1
MED.
Indi- HIGH
e/gR/c ; El 3 cator ;E;;;;
d
h El2
TEMP
i E9 COOK
j
El0 AUTO
k El1
Kg
Signal
E7
E7
E7
E7
E7
El9
El8
El7
E6
E6
E6
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