# tsRB195AB RevB 03/30/2011 2
DC FAN MOTORS
Brushless DC Fan motors are used to save energy. The fans operate at two speeds,
High - when the ambient temperature is high and Low - when the temperature is low.
Generally, it is operated in the High mode during a day time and in the Low mode at
night. This circuit design is to protect the Main PCB from a failed fan motor.
Fan speed information is read by the Main PCB. If the fan speed exceeds 600 RPM or the speed is too slow or stopped,
the fan drive circuit is disabled, After 10 seconds, the circuit tries again with 3 seconds of DC voltage If the fan continues this activity for 5 cycles, 10 seconds off 3 seconds on, the fan drive circuit is disabled for 10 minutes.
TO TEST THE FAN CIRCUIT VOLTAGE.
Power off and back on to check the DC voltage to the motor, wait from 10 to 60 seconds for the fan voltage to kick in,
and then check fan voltage, the average reading is 9 VDC. If you get 3 seconds of voltage every 10 seconds for the 5
fan power up cycles, then the Main PCB is good.
NOTE: You may need to put unit in FORCED FREEZE mode to activate the fans/compressor.
If the fan blade is blocked by ice, disconnect the power cord, then defrost and check the motor again.
If the evaporator is ice blocked and thus blocking the air flow, the fan will over RPM and is stopped. Remove ice and
check the motor again. If everything is clear around the fan blade, then the motor would be at fault. Continuous fan errors will be displayed on the front panel display. PLEASE NOTE: The door switches control the evaporator fan motors.
Have them closed to test the motors. Delay time 10 – 60 seconds.
An intermittent evaporator fan door switch could cause an intermittent no cool condition.
Shattered Ice – Flex Tray
When all ice shatters, it's because of a bad
tray or ice cube temp that is too cold (lower
than -5 degrees). In some areas, there are
water issues that can also cause shattered
cubes. The temp in the freezer should not
have any effect on this issue, as long as it’s
below 1.5 degrees F, as a properly installed
sensor will not read the freezer temp, only the
water/ice temp.
Check the Ice tray for defects in the plastic.
Ice that is too cold will shatter during
harvest. This can be from the (1) sensor not
reading the correct temp (2) or the sensor not
mounted correctly (3). By programming the
icemaker offset value to a lower number (4),
the board not understanding the reading.
To check the sensor, you must check the tray
temp (not air temp) and compare it to the sensor reading. The sensor should read 3.7 volts
at the main board connector when the cube
temperature is 1 degree. After the fill, the sensor will read water temp 1.5 to 2.2 volts.
To clear offsets, put unit into Diagnostics
mode.
Please note, some shattering is normal for
a flex tray icemaker.
FLEX TRAY Ice Makers
When the initial power is applied, the ice tray will stand by for 2
hours. After the 2-hour standby time, the Ice Maker Sensor will check
the temperature , when it is lower than 1.5℉ for more than 5 minutes,
it will do a harvest, with or without ice in the tray, then fill with water.
58 minutes after water is supplied to the Ice Tray, the Ice Maker
Sensor temperature will be checked. When the Ice Maker Sensor
maintains lower than 1.5℉ for 5 minutes, it completes the harvest
(if the ice bin is not sensed as full).
Thermistor senses temperature to determine water fill on newer units
Filling the tray
After the water fill is completed, the ice maker sensor will evaluate the
water volume one and a half minutes later. When it detects no or low
water level, it will add more water. First supply time will be 1.5 sec,
next one will be 1 sec and the last will be 2 sec.
Guide – Bin Full
Ice Maker Thermistor
Ice Maker Test Button
The Refrigerator Reed Switch and
Magnet must be aligned for proper
cooling operation.
The Top arrow shows the hinge
improperly aligned, the Lower
arrow shows the correct position
of the hinge