Appendix Ⅰ Ⅰ (Reference For Circuit Diagnostics) - Samsung RS2544 Service Manual

Appendix Ⅰ Ⅰ (Reference for circuit diagnostics)
Ref.1) Wire connector on the cabinet door.
Ref. 2) How to check relay failure
Note) NC -> Normally Close (C terminal and ON terminal)
NO -> Normally Open (C terminal and Open terminal)
C -> Common Terminal
Div. of contact Voltage at both terminal of coil and trigger Both terminals of contact
DC 12V (Working Condition)
3-contact
terminal
DC 0V (Stop Condition)
Relay
2-contact
∼ DC 12V (load working condition)
terminal
∼DC 0V (load stop condition)
Relay
∼DC 12V (load working condition)
SSR
∼DC 0V (load stop condition)
Disconnect the connector of the main PCB
CN70 and CN71, then check the follows :
1. Measure the voltage at both terminals of a coil and
determine if the relay is working.
2. Measure the voltage at both terminals of a trigger and
determine if SSR is working.
3. Measure the resistance at both terminals of a load
contact, and determine if there is an error in voltages of
coil and trigger.
Resistance value
Between C and NO 0Ω (Short) -> Normal
∞Ω (Open) -> Normal
Between C and NC
Between C and NO ∞Ω (Open) -> Normal
Between C and NC 0Ω (Short) -> Normal
Between both termi n al s of contact 0Ω (Short) -> Normal
Between both termi n al s of contact ∞Ω (Open) -> Normal
㏀
Between both termi n al s of contact
About 4-5
Between both termi n al s of contact
∞Ω (Open) -> Normal
75
(Short) -> Normal