Friedrich MM18YJ, Service Manual

Page: 43 / 83

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Measure the voltage of this foot to neutral
wire on the mainboard
Troubleshooting for
H6 malfunction
Stir the blade
with a tool to see whether
the blade rotates
smoothly
Is the
control terminal of PG motor
connected tightly ?
Replace PG motor
End
yes
no
Is malfunction
eliminated
yes
no
Insert the control
terminal of PG
motor tightly
no
no
Stir the blade by
hand to see whether
the blade rotate s
smoothly
Reinstall the blade and
motor correctly
Is malfunction
eliminated
no
no
yes
yes
Turn on the
unit again ; measure whether the output
voltage on control terminal for PG motor
is more than 50V within 1 min after the
louvers are opened
no
yes
yes
Is the motor
started up
no
Is malfunction
eliminated
yes
yes
yes no
yes
Is malfunction
eliminated
Tighten the screw; reassemble the blade, motor
and shaft bearing rubber base sub-assy to make
sure there is no foreign object between them
Replace the mainboard
with the same model.