Introduction
If you are faced with a Tesla Gen 3 Wall Connector that is showing No Power and No Lights or Indicator LEDs it could be that a Fuse; the Offline Switch IC; the MOSFET has blown on the back of the main board.
In this repair scenario, a bug carcass was found fused to the Offline Switch IC which led to the Fuse blowing and the MOSFET along with it. The exact cause could be something else, but a good stories needs an agent.
-
-
Huge thanks to @korganlibrahim for allowing me to use his very well done teardown of the unit, which I also used to guide me.
-
-
-
Located on the front of the main board just besides the mains terminal connector you will find two Ceramic 10W 50 Ohm fusible through hole wire wound resistors.
-
The fuse on the right is tied to the specific area on the back of the main board where we had our blown component.
-
Using a voltage meter and while the unit is connected to an AC power source, the bottom of the Fuses should have the same reading as the input AC voltage, if not your input might be incorrectly connected or another fault may be present.
-
If the top of the Fuse does not measure the same as the input AC voltage this indicated the Fuse is blown.
-
-
-
The Offline Switch IC is UCC28742DBVR driver with markings U742 on it. The MOSFET is a STD4N80K5.
-
The other components are: R121 - R123 - 2M Ohm 1206 Resistor, R124 - 4K Ohm 0402 Resistor, R125 - 0 Ohm 0402 Resistor, R126 - 1.47K Ohm Resistor, R127 - 36K Ohm 0402 Resistor, R128 - 0.2 Ohm 1206 Shunt Resistor
-
-
-
The bug was able to find its way inside the main board section of the chassis via the openings around the cable entry. While rain cannot enter from this bottom up location, insects still can by crawling in.
-
To reassemble your device, follow these instructions in reverse order.
