7
driver,remove the five self tapping screws that secure the
bottom motor cover to the front motor cover.
Remove the two flat head and two round head screws that
secure the bottom motor cover to the right and left hand side
panels.Carefully pull back the bottom motor cover enough to
gain access to the components within.You may find it
necessary to disconnect the leads to the power cord
receptacle and fuse holder to completely remove the bottom
motor cover.Make careful note of these connections as to
re-connect them correctly later.Once you have gained
adequate access to the heat control board,you can now
remove and replace the ribbon cable(it disconnects from the
control board the same as from the digital display board
explained previously).
Now we can test the heat control board.Disconnect all the
wire leads from their respective terminals(make note of their
locations to ensure proper re-connection later).Using a multi
meter set to
k
ohms,put one probe on terminal T4(common)
and the other probe on terminal T1(208 v).You should get a
reading of approximately .910
k
ohms at room temperature.
If it shows open(infinite) or closed (no resistance) the board
is faulty and should be replaced.
Next with a probe on T4 again and the other on T2(240v),
you should get a reading of approximately .765
k
ohms at
room temp.Again,if it shows an open or closed reading the
board is faulty and should be replaced.
With one probe still on T4 and the other on T3 you should
get a reading of approximately .410
k
ohms at room temp.If
it shows open or closed,the board is faulty and should be
replaced.
