Intercom Problem

[flybill7]

Looking for some suggestions on how to troubleshoot an Intercom issue in my 7. I have a PS Engineering PM3000 that has been working great for 240 hours. But recently it started giving me trouble. Basically it doesn't work after I start the engine. It'll power up but then the power will go on and off intermittantly. The funny thing though, as soon as I take off, it works perfectly for the rest of the flight and even on the ground. I'm going to start by checking the fuse, but after that I'm out of ideas, other than just checking wiring, which will be a major pain. Any ideas are welcome!

... Bill

 

[Mike S]

You have given a clue or two to where to check------

Think about what is different between the times when it is working, and when it is not.

As I read your post, it works fine on the ground until the engine starts, then after take off, the unit works well again.

I see two things that could be involved here-----big one seems to be vibration level caused by the engine. This would probably result in a loose connection acting up.

Ground wire, or power wire????

Other thing to look at is voltage issues, voltage will drop off a bit after you use the starter, and then when powering up to take off, the alternator will start putting out enough to make the electric system happy-----but usually not at idle.

Good luck

 

[ScottHess]

Perhaps remove the plug and run a jumper to the power pin. See if you are in fact losing power when starting. That should be simple enough and will at least determine whether you have a bad intercom or not. Maybe you'll be lucky and reseating the plug itself will cure the problem.