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FlightCom 403 doorstop?

LarryT

Well Known Member
I am beginning to think the Flightcom 403 intercom in my plane has a highest and best functioning purpose as a doorstop.

However, Before I plunk down hard earned dollars on a PS Engineering PM500EX and a wiring harness, I would like to describe the progression of symptoms to you electronic gurus and see if you conclude that there aren't any other areas of concern.

1. When I bought the plane, the radio worked great - especially after I got a Halo headset.

2. Unfortunately, due to economic reasons the plane sat for a while. When I fired it up after the long layover, I noticed that there seemed to be more background noise than before. There was less noise in the "Isolate" position than the ICS position.

3. A week or two later, I took my daughter flying with me locally. We had difficulty communicating over background noise.

4. On a second local flight one week later, I turned up the volume control for her DC headset and that seemed to help. I still observed more background noise in the ICS position than ISO.

5. During my solo flights from W52 to Tucson and San Diego, I began to notice a "whistle" in the radio when set to the ICS position.

6. The airplane was on the ground in San Diego for 5 days and my daughter had decided to fly back with me. I plugged her headset in and the "whistle" was so unbearable in ICS mode that I had to turn it off. That greatly diminished her enjoyment of the trip home since we couldn't carry on a conversation.

7. I have been flying twice since I got home August 14th. The first time about 3 weeks later. Now there was a "whistle" even in ISO. Another 3 weeks go by and I fly again. This there is no side tone at all in ICS, but a radio check in ISO gets a loud and clear response.

How on earth does electronic equipment degrade while the plane is sitting in the hangar? Is this progression indicative that the problem is in the intercom and not something else? Sending the intercom to Flightcom, including shipping to/from is practically what Van's charges for a new 403. I had a PS audio panel in my Cherokee 180 and it worked perfectly for 9 years from the day it was installed until the day the aircraft left my possession. Money is tight these days. I just want to make reasonably certain that it is the intercom and not some other contributing factor. If you got all the way through this lengthy post, thank you. If you have some sage advice, thanks even more.

Larry Tompkins
544WB -6A
W52 Battle Ground WA
 
Flightcom

This exact thing happened to me the other day while flying aerial detection for 6 hours. Started out with clicking, progressed through the day to the point that it was unbearable at 5.8 hours. Only way I got in to the field was to pull the power all the way off just to get in a call and hear "cleared to land". Lost the rectifier in the alternator. I have flightcoms in all 3 airplanes and they work great. Good luck.
Don
 
Larry, have you tried swapping both headsets out? Maybe borrow some just to eliminate headset issues. How does it sound on the ground before firing up the engine/alternator?

Just thinking out loud to help trouble shoot the problem. That's what I would try first.
 
After you change headsets- Is is a whistle or a whine (whistle being much higher in pitch). Does it change with engine RPM? Alternator on or off?

Just an FYI, electrolytic capacitors (often used in noise filters) don't like to sit long periods and without use and can fail.

Dan
 
Responses to posts

#1 Don: In flight, my voltage meter reads about 14.2. My ammeter shows a draw of -2 amps. Does this sound like a potential alternator problem? Is a rectifier the same as a diode? If memory serves me correctly there are 3 diodes to convert AC to DC.

#2 Gil: Neither headset is noise canceling type. Halo is in ear type and DC are old passive headset that I put confor-foam ear pads on. I have plugged each into my pilot side headset jacks w/o any difference.

#3 Gary: Thank you for that suggestion, I will try it and report back.

Larry
 
flightcom

I had good voltage also but had lost one of the diodes. I exchanged mine for a rebuild, think it was $395 from Quality Aircraft Accessories and all was well again. Were you able to communicate a little bit with the power pulled all the way back in flight? At cruise power there is no way to communicate at all. Sorry, I think it's going to cost you a little money.
Don
 
You can give SteinAir a call. He periodically post here about good deals on used or NIB units that get returned due to panel upgrades that get done before the original design gets implemented. I called Stein this past week and was able to stag a returned new-in-box SL-40 for a good price.

Stein had not yet advertised this unit on this VAF web site, but was getting close to advertising this unit as well as some other items. I felt lucky that I got what I wanted for a good / attractive price. Give him a call.
 
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I bought my stereo 403 on eBay for about $30 and have roughly 500 trouble free hours on it. You could search there for one as a temporary or permanent replacement.
 
Here is an update

At Don's suggestion, post #2, I removed the alternator and had it tested. It passed all three checks including diode check. Output V = 14.8 Ripple 0.49

At Gary's suggestion, I tried the intercom with the engine off and there was no interference, whistle, etc. Currently, I am doing brake work so I can't start the engine in the hangar.

I will look for a used 403 on the internet to swap out and see if that matters. Or if anyone of you have one that you could loan, I would gratefully accept a loaner.

Larry
 
Not likely to work, but inexpensive to try: go to radio shack and buy contact cleaner. Spray the volume controls and switches from inside the box. Remove all connectors, spray all pins. Reassemble and try again.
 
I have one for you

I just upgraded my radio and do not need my Flightcom 403. It works great. Make me an offer I can't refuse. If it doesn't solve your problem send it back.
 
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