Samsung RF28R7201 AA Series Service Manual page 61

TROUBLESHOOTING
※ R Self-diagnostics check list
LED
Item Diagnostic method Location image
F R
Check the soldering status of the
inverter PCB. (Check if any parts have
 ~ 
Comp IPM Shut short-circuited).
Down Error Check if the DC 15V output is less
than 13.5V. Check the Comp and
Cycle.
61