Sharp R-8R51 - Page 23

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ROARATIW)
RORRSVB)
TEST PROCEDURES (CONT‘D)
PROCEDURE
LETTER COMPONENT TEST
b) For a certain digit, brightness ts low.
c) Only one indicator does not light up.
d)} The corresponding segments of all digits do nat light up; or they continue to hight up.
e) Wrong figure appears.
f} Acertain group of tndicators do not light up.
g) The figure of all digits ficker.
2-3 Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b} Clock does not operate properly.
c} Cooking is not possible.
d) Proper temperature measurement is not obtained.
R PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD (PWB) IS OPEN.
To protect the electronic circuits, this model is provided with a fine foil pattern added to the
primary on the PWB, this foil pattern acts as a fuse. If the foil pattern is open. foliaw the trou-
bleshooting guide given below for repair.
Problem: POWER ON, indicator does not light up.
CARRY OUT 3D CHECKS
Disconnect the leads from the primary of the power transformer. Make sure that the leads remain
isolated from other oven components and chassis.(Use insulation tape If necessary.)
Reconnect the supply.
STEPS. == —— OCCURANCE . CAUSE OR CORRECTION
1 The rated voltage ts not applied to POWER terminal Check supply voltage and oven power cord.
7, of CPU connector (CN-A) ee ae
2
The
rated
voltage
ts
applied
to
primary
side
of
T/C.
T/C
transformer
or
secondary
circuit
defective.
Check
_ transformer,
Roan
oot
and
repar,
.
3
Only
pattern
at
“a”
is
broken.
:
"Insert
jumper
wire
1
and
solder
{CARRY
OUT
3D
ee.
uke
=
Bae
:
y-
ia
ase
&
oe
_CHECKS
BEFORE
REPAIR)
4
Pattern
at
“a”
and
“b”
are
broken.
"Insert
the
coil
RFILNAOO3DREO
between
“c”
and
“d".
(CARRY
OUT
30
CHECKS
BEFORE
REPAIR)
NOTE:* At the time of these repairs, make a visual in-
spection of the varistor for burn damage and
test the T/C transformer with an ohmmeter for
the presence of layer short-circuit (check pri-
mary coil resistance).
If any abnormal condition is detected, replace
the defective parts.
W Nv
e
y3aMOd
1¥4H
CARRY OUT 4R CHECKS
BDSG CAUSUY
21