Samsung RB1855SW Service Manual page 58

Ref. 3) Check a load
* Remove the housing connected with the Main
PCB CN70 & 71,load connection terminals,
and then measure the following.
1. Judge if it operates or not by measuring the
voltage between both of the relay coil terminals.
2. Judge Open/Short by measuring both of the contacts.
3. When it operates like the above, it is OK. If not,
replace the relevant relay.
Ref. 4) Check sensors
3. R-defrost sensor measures resistance of CN30 between ④~⑤.
4. F-defrost sensor measures resistance CN30 between ③~⑤.
5. The measured value above is compared to the sensor specification and the temperature table in
speciication found in the manual.
* Unplug the power cord and disconnect the
connector from the main PCB CN70, 71 and
measure the following:
1. Measure resistance between the terminals and
check for malfunctioning of a load and wire
connection.
Measurement
Subordinate
terminal
R Defrost heater CN70 ⑤ - ①
F Defrost heater
CN70 ⑦ - ①
Comp
CN70 ⑨ - ①
Comp-circulation fan
CN70 ③ - CN71 ①
R-Circulation fan CN71 ⑦ - ①
F-Circulation fan CN71 ⑤ - ①
R-Lamp CN71 ⑨ - ①
F-Lamp CN71 ③ - ①
Voltage between both
Category of contacts
of the coil terminals
(OPERATION)
3 contacts
(NO OPERATION)
DC 12V (OPERATION)
2 contacts
DC 0V(NO OPERATION)
* Disconnect the connector from the main PCB
CN30.
* Resistance will be lowered while the
temperature rises due to a NTC type sensor.
1. R sensor measures resistance of CN30
between ②~⑤.
2. Freezer sensor measures resistance of CN30
between ①~⑤.
58
Evaluation of mea-
surement result
Voltage between both of
the contacts
C:NO → SHORT
DC 12V
C:NC → OPEN
C:NO → OPEN
DC 0V
C:NC → SHORT
SHORT
OPEN