Classic IIID/300D/SAE300/3+3 Flyback Diode Install and Points

Updated 2025-08-09 just to revise the wording. In this tutorial, we will describe how we are to install a flyback diode prior to the use of a wireless rheostat receiver.

The purpose of the flyback diode and its install is the following: It protects the receiver and your remote switch from inductive voltage spikes released from the shunts when the circuit interrupts. some newer machines have this prebuilt. But, we shouldn’t take this for granted so we are installing a redundant one. PLEASE READ CAREFULLY SO TO NOT INSTALL IT BACKWARDS

The uttermost important note is to never disconnect both wires at the same time. That way you wont mix them up or lose track.

Step #1 Coming out of your generator are two 14 gauge wires which go into the back side of the J5 connector. As seen in the picture to the right, the J5 connector is the 4x3 connector consisting of twelve spots.

Step #2 The dkw remote flyback adapter provided in 2025 has two colors: black and blue. The black wire of the dkw remote flyback adapter connects to the spade that is connected to the wire that comes out of the middle row end spot on the back of the J5 connector.

Now for the other wire, for the sake of clarity, the dkw remote flyback adapter blue wire is connected to the spade on the wire on the outer row one in (pin3 in schematic)

You can see from the description above, the dkw black wire is always connected to a middle row pin and the dkw blue wire is always connected to a outer row pin.

Step #3 At this point, very recommended to try welding a bead with your original remote or machine rheostat. Why? Because if you installed it correctly, you will be able to still adjust your heat. If you installed it backwards, it may be stuck at min heat <- never tried it though