Intercom wiring harness

[AK737]

I want to build a harness for a PS Engineering PM 3000 intercom.
I?ve got the wiring diagram and understand that I can use solder sleeves with a pigtail to daisy chain the ground, but I can?t quite picture how to string them all together, especially with the jack ring being grounded to the shield:



Can someone shed some light on how I do this? Or maybe share a couple photos?

Thanks!

Chris

[BobTurner]

Originally Posted by AK737

I want to build a harness for a PS Engineering PM 3000 intercom.
I?ve got the wiring diagram and understand that I can use solder sleeves with a pigtail to daisy chain the ground, but I can?t quite picture how to string them all together, especially with the jack ring being grounded to the shield:

Chris

First some terminology: Looking at a plug, the end furtherest away from the handle is called the "tip"; moving toward the handle, there is the "ring" (about 1/4" wide); the remainder, going up to the handle, is the common or ground. When you spoke of the "jack ring" being grounded, I think you meant the common or ground part, not the actual "ring" terminal. On a mike, the ring is the hot connection to the mike; on a headphone, it's only used for stereo. Now, as to the common or ground terminal: Standard practice is to NOT connect it to the shield. Instead, isolate the jack with fiber washers (one of which will have a lip to go inside the panel hole), and run a separate wire from the common or ground terminal back to the intercom. If the intercom has an "audio Lo" input, connect it there. Otherwise, connect it to ground on the intercom. The braided shield should be connected to ground on the intercom; cut it and leave it unconnected at the jack end. And yes, if you need to connect multiple wires to the intercom ground, it's okay to daisy chain them together with crimp sleeves; just keep them as short as possible.

[lr172]

they don't need to be strung together. Just leave a 4-6" pigtail on each. Once everything is in the connector. join all of the pigtails together, along with the wire going to the 3000's ground wire and solder up and cover with shrink sleeve.

Larry

[AK737]

Bob, thanks for the primer on terminology! I?ll get it all straight as I dive deeper into this!

Larry, thanks for your input!

For some reason my image of the diagram didn?t post. What confused me was the way the Audio Lo leads were depicted as connecting to the shielding. Sounds to me like I need to interpret that as just connecting to the common ground.

[BobTurner]

That?s correct. The PM3000 doesn?t have audio Lo inputs, so connect all of the audio common/ground wires, and the shields, to ground at the intercom. Keep the wires as short as possible. It doesn?t have to look daisy chained, as shown on the schematic.

[MCA]

Some audio panels/radios have a separate 'Audio LO' (audio ground) from the chassis ground, while others share the ground.

It's also a good idea to make sure the jacks are isolated from the metal on the panel or airframe using paper washers (made for this specific purpose).