6.2 HOW TO CHECK P.C BOARDS
MR-385R-A
MR-420R-A
MR-455R-A
MR-385R-A(NZ) MR-420R-A(NZ) MR-455R-A(NZ)
(1) Precautions
Unplug unit before checking
If the controller P.C. board box is opened with the refrigerator inside
cooled, dew will form on the control board, causing trouble such as
poor insulation.
The following cares must be taken when servicing.
1. Be sure to unplug the power cord before servicing.
2. Wipe away droplets on the control board box with dry cloth,
and dry it up before setting a new controller P.C board.
(2) How to check the controller P.C board and vicinity.
The control board box can be checked without opening the box.
Measure the voltage and resistance using 8 connectors outside
the box.
How to check with connectors
1. Check for 230/240V output during power on.
POWER ON
Make the pin No.7,9 of the 9 pins white connector as a common pin,
and measure the voltage between the common pin and
another pin.
Make sure that 230/240V is output
Note: The room light always has 230/240V.
2. Check for "thermistor" output during power on.
5 pins white connector
Make the pin No.1 of the 5 pin white connector as a
common pin, and measure the voltage between the common
pin and another pin.
Make sure that 2-3 VDC is output.
POWER OFF
3.Check for weak current wiring during power off
5 pins white connector
Remove the connector, and measure the resistance across
-No.1 pin and No.2 pin to confirm the continuity for DEF
thermistor.
-No.1 pin and No.3 pin to confirm the continuity for the
Freezer thermistor.
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