Samsung RT38 Service Manual page 51

TROUBLESHOOTING
4-2-4. When there is no Power in MAIN PCB
4-2-4-1. Area that is Rated input voltage 220~240V.
Caution
There is AC220~240V or
DC310~340V at the MAIN PCB
Power Circuit. So, be cautious
when repairing the unit or
measuring values.
- Check the connection of Door Panel
PCB
The unit is plugged in?
Yes
220~240V is applied
at MAIN PCB
CN70 terminals?
Yes
MAIN PCB Fuse is blown?
No
DC310~340V is applied
at BD1+/- terminals?
Yes
DC 6.2V is applied at
TOP S/W 3-12(BETTER),
2-8(GOOD)?
Yes
12V is applied at
CE109 terminals?
Yes
5V is applied at
CE113 terminals?
Yes
Panel PCB operates
normally?
Yes
Loads such as Relay
operate normally?
Yes
Is there PCB Short
or breakage?
No
Normal (Check again)
56
- When checking the MAIN PCB, refer
to the Operation descriptions and
the "Reference" section.
No
Plug in the unit
No
Check the wire connections
Yes
1) Replace Fuse (AC 250V 2.0A)
2) Replace PCB ASS'Y
No
Replace PCB ASS'Y
No
Replace PCB ASS'Y
No
Replace PCB ASS'Y
No
Replace PCB ASS'Y
No
1) Check the wire connections
2) Replace Panel PCB
No
1) Check Lead Wire connections
2) Replace Relay or PCB ASS'Y
Yes
1) Do Re-soldering
2) Replace PCB MAIN