Step 1:
Replace PFC control board:
Remove the white glue.
Disconnect the 3-pin cable from CN7
of the PFC control board, demount
the small PCBA board.
Demount the 3 white screws,
disconnect the 50-pin cable.
Replace the PFC control board with a
new one. It is better assemble the
small PCBA first, then assemble the
new PFC control board by install the
3 screws, and then connect the
3-pin cables and 50-pin cables.