Sunday, May 4, 2014

Co-Pilot Headset Audio Jacks Installed

Wiring the RV-12 continues … have been chipping away at making labels and inserting wires in connectors. Although some time was taken away from production for the first lawn mowing of the year (a sure sign of warmer weather) and to work out a few issues with running the shielded cable for the strobes and wiring in an  additional switch for the left landing light. More on that topic when I get it finalized.

The next step in the wiring section would have the builder install the push to talk button wiring in the control sticks and mount the control sticks so the push to talk wires can be dressed properly. Decided to take a pass on dong this now because I’m leaning towards installing a stick with additional switches for auto pilot, trim, etc. so want to hold off making a final decision on stick grips until after making comparisons at Oshkosh.

Next page - the fuel pump wiring received a little attention … the fuel pump power lead from the instrument panel and the red wire from the pump receive spade connectors which will attach onto a large capacitor seen in the photo below. (Which I’m assuming is used as an electrical noise filter). The fuel pump mounting bolt closest to the wire run receives an Adel clamp which is used to suspend the wires running down the center tunnel and is also the grounding point for the fuel pump’s ground wire. The Adel clamp needs to be drilled out to 1/4" to allow the fuel pump’s mounting bolt to pass through it.
Crimping a spade connector on the fuel pump’s power wire.

The co-pilot headset and mike jacks were installed next. One thing that is important to remember is audio jacks typically need to “float” and do not get grounded to the airframe. I have read more than one complaint about noise in the audio which ultimately ended up being caused by the headset jacks being installed incorrectly.
Looking closely one can see the shoulder on the black insulating washer in my fingers … this goes inside the mounting hole preventing the threaded mounting shaft on the jack from becoming grounded on the inside edge of the mounting hole. The other nonmetallic washers will insulate the mounting nuts from the floor pan.

The headset & mic jacks are installed using the above plastic shoulder washer, however the shoulder needs to be sanded or filed down a bit because the shoulder is slightly taller than the thickness of floor pan. After the jacks are slid up through the mounting holes the flat insulating washers are used to insulate the metal shaft of the jack from the aluminum floor pan.

Return from the future: There is an error in the prints regarding the wiring of the ES-00043 headset module connectors. Figure 2 shows the wiring for the connector from the wire insertion side … caution the connector’s pin numbers as shown in the plans are wrong. An update to the plans is coming from Van’s. I did not notice or fall into this trap because I was referring to the big wiring diagram and reading the pin numbers directly off the connector itself. Below is the bad and correct wiring for the ES- 00043 headset module connector as viewed from the wire insertion side of the connector with the locking tab on the bottom of the connector as shown in the drawing.

Bad as shown       6 5 4 3 2 1
in the drawing     12 11 10 9 8 7

Correct pin           1 2 3 4 5 6
locations              7 8 9 10 11 12

Before sliding the wires into the Molex micro connectors printed heat shrink labels were made to identify the wires.
Installing the co-pilot headset and mic wires into a Molex micro connector.
Co-pilot Mic and headset jacks installed onto the floor pan.