Recall for Greenworks and Kobalt twin-blade cordless mowers

MowerMike

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  • / Recall for Greenworks and Kobalt twin-blade cordless mowers
Update on 3/24/2018

I received the replacement switch today, and the mower is again functioning properly. After examining the switch, I discovered that it actually does not operate the way I initially thought. It is in fact a complicated SPDT On/Off switch, nothing more, and has nothing to do directly with selecting the battery port. One contact is NC and the other is NO, and the two switch terminals on one side are jumpered together to a common wire. The terminals on the other side are connected to separate wires, such that the NC contact represents the Off state and the NO contact represents the On state when the bail operates the switch. As soon as the bail is released, a strong internal spring inside the switch returns it to the Off state. The On wire is connected to the safety key circuit, suggesting that it is the hot side of the circuit. The Off wire is connected to the circuit board, so it is a mystery exactly how it works. As to battery port selection, it must be done by direct voltage detection of the batteries, since all the battery connector wires go directly to the circuit board. So, the problem with my old switch was that the NC contact was not opening when the bail was operated, and not that it was not opening when the bail was released. Curiously, after I removed the old switch and bench tested it, it seems to work again, so some internal part is failing intermittenly. It is a complete mystery to me why the malfunctioning switch permitted the mower to operate with a battery inserted in one port but not the other.
 
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