Drive Motor Tachometer Error
The control is unable to properly detect motor speed and the machine will shut down. If a failure occurs during high-speed spin the door will be unlocked after 3 minutes.
Potential Causes:
* Check wire harness connections between the Drive Motor/Tachometer and the Motor Control Unit (MCU), and between the MCU and the Central Control Unit (CCU)
* Check the Drive Motor
* Check the MCU
* Check the Wire Harness
begin troubleshooting right at the motor. Why start there? Because the motor is one of the prime suspects and it's easy to check. Remove the back panel and unwind the belt from the drum pulley. Now turn the motor pulley (sans belt) by hand. If it doesn't turn smoothly and easily, you have a bad motor.
If the motor pulley turns smoothly and easily by hand, next step is to run the motor with the belt still removed from the motor pulley. If the motor seems to run fine that way, put the belt back on and run it again. If the motor won't run under load (with the belt on), then that's another sign that the motor is bad.
Suppose the motor turns easily and freely by hand but won't run either with or without the belt. This is a more subtle condition because we're probably dealing with a bad MCU or flakey wire harness somewhere between the motor and MCU, or between the MCU and the CCU.
One trick that often works at this point is to remove and reinsert all wire connections at the board and motor. This tends to clean the small amount of corrosion that will build up on the connections. After you do this put the machine into a service cycle (see the instructions in the tech sheet found inside the unit or you can ). Part of the service cycle is running the motor at certain set speeds which checks the tach.
If you've removed/reinserted the wire harnesses and still no joy, then usually the problem is the MCU.
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