Intercom

[amillet]

My factory installed Symphony intercom quit in the middle of my PPP flight today.  I’m looking for your input on repairing it or getting a new audio panel wit intercom built in. Garmin or PS Engineering?  I have a GTN 750 in the panel already 

[bradp]

The 350C has some nifty Telligence voice commands that you can train.  If you're into that the garmin suite is well integrated and you can remote mount an audio panel.

 

PS Engineering is just solid.  The 450B can support multiple bluetooth connections and is probably the "flagship" of audio panels.  I have a 8000Bti (bought used) and absolutely love it.  It just works.  One of the best upgrade decisions I've made so far.   It too will work well with your 750 but you wouldn't get the remote or voice command features - those  should be your decision points.  If you don't want them then go with PS Engineering.  Their customer service and support is top notch as well.

 

I wouldn't put much effort into repairing your intercom - it may be worth finding a used one on Ebay for $40 bucks and seeing if it works before committing to several AMUs for an audio panel. 

The real cost of audio panels are in the wiring- either be handy and prewire for 4 places or be prepared to see 20-30 hours for installation.  Your audio panel connects to pretty much everything else in the cockpit. 

Hope this helps. 

[LANCECASPER]

The Symphony 468 DRE Intercom which you have that Mooney installed in the mid to late 90's was way ahead of anything else at the time. It was stereo, digital with some great customizable features. A simple thing to do is just unplug the old one and plug in a used serviceable one. I have one and sent you a PM.

[amillet]

Thank you. I’ll check it out when ai get back home. Hoping it is just a loose plug .  

[amillet]

Traced the wires as far as I could into the bundles under the glare shield. Nothing obvious. Time for a trip to the avionics shop

[amillet]

Tech at Command Aviation in Bellingham, WA found no power to intercom. He ran a new wire from circuit breaker to plug and got it working again. Two hours labor 

[kris_adams]

Doesn’t get much better than that!

[amillet]

Yes, $200 vs $5K for a new audio panel/ intercom.

[Eaglebeak]

Would anyone happen to know where the factory installed DRE 468 intercom box is located on the M20Ms? It doesn't appear to be adjacent nor behind to the DRE controller on the instrument panel, nor is it on the Pilot side panels. POH indicates it should be 30 inches from datum, whereas instrument panels is about 17 inches from datum. I am trying to troubleshoot high volume static noise and want to isolate box from wires to make sure it isn't something as simple as an intermittent ground short.

[Baker Avionics]

2 minutes ago, Eaglebeak said:

Would anyone happen to know where the factory installed DRE 468 intercom box is located on the M20Ms? It doesn't appear to be adjacent nor behind to the DRE controller on the instrument panel, nor is it on the Pilot side panels. POH indicates it should be 30 inches from datum, whereas instrument panels is about 17 inches from datum. I am trying to troubleshoot high volume static noise and want to isolate box from wires to make sure it isn't something as simple as an intermittent ground short.

With or without engines running?  Only on Intercoms or also on Comm?  Have you had engine work done lately?

[Eaglebeak]

15 minutes ago, The Avionics Specialists said:

With or without engines running?  Only on Intercoms or also on Comm?  Have you had engine work done lately?

With or without engines running? Both

Only on Intercoms or also on Comm? When power is on to Intercom. Comm works fine (Pilot and Emergency only) when circuit breaker to intercom is pulled.

Have you had engine work done lately? Problem started about 10 hours after annual.

My temporary remedy is to disable intercom by pulling breaker. Then I attached an old 4 port portable intercomm and PTT switch to Emergency Jack and Mike. 

 

Edited October 22, 2018 by Eaglebeak
typo

[Baker Avionics]

3 hours ago, Eaglebeak said:

With or without engines running? Both

Only on Intercoms or also on Comm? When power is on to Intercom. Comm works fine (Pilot and Emergency only) when circuit breaker to intercom is pulled.

Have you had engine work done lately? Problem started about 10 hours after annual.

My temporary remedy is to disable intercom by pulling breaker. Then I attached an old 4 port portable intercomm and PTT switch to Emergency Jack and Mike. 

 

Ok, perfect!  Good info!  Do you have a CB for the Turn Coordinator?  Check that also.  One thing to look at is to see if the headset and mic jacks are actually isolated from ground.  They SHOULD be grounded through the intercom unit itself, ONLY! If they are not isolated from the airframe and grounding there, they can pick up noise as well.  Also, we need to be sure that the wiring going to the mic and headset jacks are shielded correctly.  

[LANCECASPER]

3 hours ago, Eaglebeak said:

Would anyone happen to know where the factory installed DRE 468 intercom box is located on the M20Ms? It doesn't appear to be adjacent nor behind to the DRE controller on the instrument panel, nor is it on the Pilot side panels. POH indicates it should be 30 inches from datum, whereas instrument panels is about 17 inches from datum. I am trying to troubleshoot high volume static noise and want to isolate box from wires to make sure it isn't something as simple as an intermittent ground short.

Here's what the box looks like . . .

[Eaglebeak]

2 hours ago, The Avionics Specialists said:

Ok, perfect!  Good info!  Do you have a CB for the Turn Coordinator?  Check that also. 

I will look into it.

One thing to look at is to see if the headset and mic jacks are actually isolated from ground.  They SHOULD be grounded through the intercom unit itself, ONLY! If they are not isolated from the airframe and grounding there, they can pick up noise as well.  Also, we need to be sure that the wiring going to the mic and headset jacks are shielded correctly.  

Which leads me to trying to locate where the intercom box is located. I need to isolate the wires to the box to verify the grounding!

And...

1 hour ago, LANCECASPER said:

Here's what the box looks like . . .

Thanks for the photo! I sort of had an idea what it look like and it's size. 

However, where is it installed? I want to avoid ripping out instrument panel to follow wires from controller to the box and possibly break something else. I'm hoping someone who had one taken out of their Mooney might provide a location.

[amillet]

I believe mine was under the glare shield right behind the panel mounted control head

[Eaglebeak]

12 minutes ago, amillet said:

I believe mine was under the glare shield right behind the panel mounted control head

Thank you for your input.

I didn't see it behind the panel control head initially, which led me to check the POH's distance to datum. This was why I thought Mooney might have installed it at a different location further from panel. 

I will check again.

Edited October 23, 2018 by Eaglebeak
addendum

[LANCECASPER]

15 minutes ago, Eaglebeak said:

2 hours ago, LANCECASPER said:

Here's what the box looks like . . .

Thanks for the photo! I sort of had an idea what it look like and it's size.

 

Did you also know it was black and had a textured finish? I figured since you hadn't found it yet, it may help to know what it looks like. 

[Eaglebeak]

1 minute ago, LANCECASPER said:

 

Did you also know it was black and had a textured finish? I figured since you hadn't found it yet, it may help to know what it looks like. 

Yes. Thanks!

[Eaglebeak]

Found it! On the M20M, it is located behind co-pilot panel, left of rudder pedal, covering the nose-gear wheel well.

Thanks for all your feedback!!

 

Now to troubleshoot this baby...

 

[carusoam]

Looks like it may have fallen from above...

Depending on the activity of the co-pilot, it looks like it might get worked over, mechanically...

Kind of an odd spot, if that is the factory chosen position...

Best regards,

-a-

[Eaglebeak]

It was factory mounted on press-fit studs on side of wheel well, then covered by a panel so as not to be kicked by co-pilot - see photo enhancement of two of the studs.