Bose headsets & E-buss?

[Caveman]

Guys, I could use some help.

Back ground: I have an RV-7 with a simple dual buss single battery Aeroelectric electrical system.
I have a PSE PM3000 intercom.
I purchaed a Bose headset and loved it, so I purchased another for the spouse and it has never worked correctly since day one.
In the stereo mode, she only hears from one ear cup.
If I turn switch 6 to the mono mode she hears from both, but the volume is way low. If she turns her volume up to max on the headset and sets the intercom volume were she can hear it, the volume is way too loud for me, even with my headset volume all the way down. The ANR does seem to work for her.
I called PSE and they said there should be no problem as they use Bose headsets when demonstrating their products at the shows.
I checked all the wiring to the jacks and confirmed the isolation washers were installed.
I have a DC Clark H10-13.4 and a Lightspeed QFR and they both work fine on her side, but she much prefers the comfort of the Bose.
I also troubleshot her set while setting in the airplane, while having a Bose rep on the cell speakerphone with the wife there to help explain. After going through their troubleshooting list he asked us to send it back. It tested o.k. on their bench, so we got it back and it acts the same way. We called them again and the tech had us return it a second time. He did mention that the only thing he could think of that would cause the problem would be a low voltage situation. (This is a battery powered headset). While we were troubleshooting I had the airplane hooked up to a battery charger just to make sure low voltage to the intercom was not a factor.
That got me thinking... my intercom is on the E-buss. Would the diode cause enough voltage drop to show these symptoms? The tech called while I was at worked and asked what kind of airplane we had and the wife told him. He wants me to call him tomorrow. I have noticed what seems like a disproportionate number of Bose headsets for sale on VAF. Am I the last one to figure out that there is a problem with running 2 Bose sets with a PM3000? I know the PM3000 requires something like 13 volts to work correctly. Any input appreciated.

 

[Caveman]

Further Testing

I moved the intercom power to the main buss. No joy. Intercom voltage drop across the E-buss diode doesn't appear to be the problem.

I found that "my" Bose headset was left in mono mode from the last round of testing. It actually is acting the same as the "wife's" set when plugged in to the passenger side... i.e. it must be in mono mode to hear out of both cups and when placed in mono mode it halves the volume of the passenger side headset. ANR seems to work on both sides of the plane.

I unplugged the I-pod from the entertainment jack and it made no difference. It acts the same when listening to AWOS only.

I shut off the AFS EFIS thinking perhaps the voice inputs were part of the issue... no change.

The Lightspeed QFR works fine with the Bose in stereo mode regardless of where each is plugged in.

It doesn't appear to be a Bose problem.

The intercom end of the harness was wired by an avionics shop. I may have miss wired the passenger side jack? It looks like more panel diving is in order. I already looked for stray strands of shield touching.

Any troubleshooting tips appreciated.

 

[647jc]

The intercom manual describes two volume adjustment pots, one left and one right for the passenger headphones. This would not explain your symptoms exactly but might be worth your time checking. The puzzling part is the QFR works in stereo mode on the passenger side where the Bose does not.

 

[Caveman]

Hah! Got 'er fixed!

The intercom manual describes two volume adjustment pots, one left and one right for the passenger headphones. This would not explain your symptoms exactly but might be worth your time checking. The puzzling part is the QFR works in stereo mode on the passenger side where the Bose does not.

Hi Joe,

When I called PSE awhile back, they told me those pots only adjusted volume for the rear seat passengers in a 4 seat aircraft, not between copilot and pilot. But your statement about the QFR got me thinking.... There are at least 3 QFR models and mine is the ANR "XC" Cross Country. Some are mono only. And some are stereo. I used mine in my old Cherokee for years. It hit me that it was a mono installation and there might be a switch on the headset that I'd forgotten about. Sure enough, a little internet research proved it did have a stereo and mono mode both. When I flipped it to stereo, it had the same symptoms as the wife's Bose, proving I had a wiring problem with the co-pilot audio wiring. I went panel diving after work and found that the three wires going to the jack were the right colors and re-confirmed continuity back to the correct pins on the PM 3000. What the heh! Never one to give up easily, I started clipping wire ties until I found enough slack I could remove the jack. Once that was done a close examination turned up a bad place where apparently "one who shall remain nameless" must have melted through some insulation with a hot soldering iron, effectively shorting the wires and turning it into a mono jack and it had gone unnoticed. As long as the QFR, or Bose, was in mono mode it worked but at half volume. An hour later everything was back together with new solder, heat shrink and it was thoroughly tested. The wife showed up at the hangar with a sack lunch and then we took a long walk down the taxi-way. She has her cherished headset working and life is good! Thanks for your help.
p.s. The Bose reps were very helpful and understanding while trying to troubleshoot my issue and one of them even built an RV-6. When I told them I had found the problem they told me they wouldn't even tell the wife it was my... 'er nameless's fault!