Heating
zones
of
the
same
side
would
display
“U”
:
Check
if
the
Power
board
and
the
display
board
are
connected
properly?
Check
the
connection.
No
Yes
Connect
a
test
display
board
to
the
Power
board.
Restart
the
unit,
does
the
symptom
continue?
Connect
the
display
board
to
a
test
Power
board.
Restart
the
unit,
does
the
symptom
continue?
Connect
the
display
board
to
the
Power
board
properly.
The
display
board
is
damaged.
Replace
the
display
board.
The
Power
board
is
damaged.
Replace
the
Power
board.
No
Yes
Yes
Perform
the
operation
again
and
check
if
it
is
working
properly.
No
:
Test
board,
means
a
normal
display
board
or
a
normal
Power
board.
Replace
the
Power
board
and
the
display
board.
- 25 -
4-3 Electrical Malfunction