DIR EHU Rebuild

The DIR EHU was the easiest one to rebuild. It was basically intact when removed from the antenna. The only problem was that one of the tapes was partially extended and extruding from the EST as seen in Photo 1. I didn’t immediately know what caused this but I figured it out later when I tested the EHU after the rebuild.

Photo 1 – DIR EHU after it was removed from the antenna – one tape was not fully homed

After removing the base plate assembly from the housing, I removed all the outer heat shrink tubing where the wires from the motor were hardwired to the control cable.

Photo 2 – Heat shrink tubing covering the wiring was removed.

The wires from the motor were not long enough to reach the newly installed connector board. So I left a small piece of control cable connected to the motor wires and soldered them to the connector board. Sticky tape was used to hold the wires to the base plate.

Photo 3

The base plate assembly was now ready for the tape spools.

Photo 4

The spools were installed and the base plate assembly was re-installed back into the housing. The tapes were brought through the EST and the bullets were installed.

Photo 5

I then took it outside and tested it with fiberglass poles temporarily installed. That is when I saw that there was a slight bend in the tape when it was nearly fully extended. My theory is that the the tape met blockage in the fiberglass pole (remember 3 of 4 poles were blocked with grassy debris). When the end of the tape hit the debris, it caused the tape to bend. This more than likely caused the tape to disengage from the spocket for a short period of time. Luckily, the tape went back onto the sprocket and I didn’t end up with a mess of tape inside the EHU. With the tapes extended, I pulled off the fiberglass tube and located the bend in the tape. I was able to bend the tape back into place with my fingers. I tested it again and the bend was gone. The EHU was ready to go.

Photo 6 – Setup used to test the EHU with poles temporarily installed