Samsung RM255BABB Training Manual page 61

DIAGNOSTIC
6-1) If power is not ON
Caution!
At the power of main PCB, the 115V AC and a high-voltage over DC 170V occur.
Please be careful wih repair and measurement
Check at the SMPS PBA.
- Check Main PCB connection.
- Check the connections between upper
hinge and CABI-door.?
- Check the connections between door
and panel PCB.
Start
NO
Is it plugged in?
YES
NO
Is 115V AC applied to both
terminals of CN1?
YES
YES
Is fuse on the SMPS PCB
breaking?
NO
NO
Is 170V DC applied to both
terminals (+ and -) of BD1?
YES
NO
Is the 5.8V DC vol t age appl i e d between
C and S of TOP S/W 246Y?
YES
NO
Is 12V applied both
terminals of C16?
YES
NO
Is 5V applied both
terminals of C19?
YES
NO
Does Panel PCB work
normally?
YES
NO
Is the load, such as
of relays and others normal?
YES
Is there any short or
break of PCB soldering?
NO
Normal
60 60
To check the main PCB, please see
the "operation descriptions and
references" in the manual.
Plug in again and check for loose
plug.
Check the connection and
assembly of electric wires.
Exchange fuse (AC 250V 2.0A)
Check PCB Pattern and replace
BD1.
Replace PCB Assembly.
1) Replace U4(D10LC20U)
2) Replace SMPS PBA
Replace REG1(KA7805)
1) Check and troubleshoot the
assembly of electric wires.
2) Replace panel PCB.
1) Replace the corresponding relay.
2) Check the contact of lead wire.