Samsung RM255BABB, RM255BASB manual Diagnostic, If power is not ON

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

Start

To check the main PCB, please see the “operation descriptions and references” in the manual.

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.

Is it plugged in?

YES

Is 115V AC applied to both

terminals of CN1?

YES

Is fuse on the SMPS PCB

breaking?

NO

Is 170V DC applied to both terminals (+ and -) of BD1?

YES

Is the 5.8V DC voltage applied between C and S of TOP S/W 246Y?

YES

Is 12V applied both terminals of C16?

YES

Is 5V applied both terminals of C19?

YES

Does Panel PCB work

normally?

YES

Is the load, such as

of relays and others normal?

YES

Is there any short or

break of PCB soldering?

NO

Normal

NO

NO

YES

NO

NO

NO

NO

NO

NO

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.

60