MGL V6 Failure

[lpaaruule]

I don't recall you mentioning anything about the headphone jack isolation. Since the radio worked fine with an external battery, perhaps you have a ground loop there. Though the antenna being attached to chassis ground may end up just recombine the grounds.

An oscilloscope sounds like a good idea, but you will see noise. I'm not sure what the acceptable level would be, or the plan of action from that point. Though others may have some good ideas.

[fastj22]

Sorry if this has been asked and answered,
1) does it lock up immediately after starting the engine or when you trigger the transmit?
2) does it lock up after raising RPM to the point the alternator starts charging the system (~2000 RPM)?
3) with the engine off and just on battery, everything works fine? TX and RX?
4) the bottom of the V6 display shows the TX/RX power level, are either pegged?
5) did you use the harness that MGL sells or fabricate your own?

On a side note that might be a culprit, when I fly past (same altitude) one of Denver's high power broadcast antennas, my radio locks up as its overpowered by the signal until i get past it. I have to turn down the radio for a few minutes because of the static. I asked MGL about it and they said it was normal. Could your Jab be creating a lot of VHF noise that is just saturating the poor thing?

[sport65]

I have checked the headset jacks several times to see that the insulating washers were seated correctly.
Which reminds me, My Aux audio jack(music) did not come with insulator washers, so I thought it did not need them, but it does. So I made insulator washers for it (cant buy them for that size). might be the cause of some of the noise some people are getting on theirs. Did not help my problem though.
I don't fully understand ground loops, but I was thinking the ground loop was not associated with power. But rather the wiring of the components (PTT, ADSB, Transponder, etc..) and the shielding to the frame, which stayed the same when I used an external battery ( the radio wiring is still shielded to the frame). In other words, It would have still ground looped on the external battery with the engine running was my thought.

1) It takes a little bit to lock up most of the time, 5-60sec of TX and RX. But sometimes it has been immediate.
2) It did, but only to about 1100rpm, my alternator starts charging pretty low. but the ferrite beads I believe got rid of the rpm effect. its a time issue I believe now.
3) Yes, works fine on battery TX and RX.
4) TX and RX levels are normal, nothing pegged
5) All harnesses are MGL except for extender because they did not sell a harness for it when I wired it up, I only had to do some connections.
I'm not flying it when this happens, it happened at two different airports.

I have to start trying something, so I'm going to try a eliminator filter that is suppose to "clean" the DC power since the ferrite beads seem to work some. It should clean noise from the alternator AND ignition to the radio since I've been told they both can be problems on a Jabiru, and those are the only things that change when the engine is running (I think). If that does not do it, then I'll try resistor spark plugs.

Thanks for all the feedback!
I will update in a bit.

[tx_swordguy]

Hey Jeff, Just re-reading your posts. You say it fails while running on the engine. Let me see if I understand what you are saying. It works fine with external battery/engine running. It works fine with onboard battery engine NOT running. With engine running/onboard battery it appears to work (display is there and all functions appear to work but you cannot TX or RX). Is there noise all the time through your headset without doing anything? Is there noise during TX? Is there noise during RX? or is it completely quiet during all these times? If it is quiet I am at a loss. If you get noise at certain times try running on one mag for a while and then the other to isolate it to one side of ignition or the other if possible. It could be that your stator is putting off so much noise it is flooding the radio. The noise I got was only on one mag and it was only during RX (most noticeable from farther away aircraft) It is possible your settings may need tweaking. MGL radios have an unbelievable range of settings which can be great, but they can also cause you headaches trying to figure out what works with each individual headset. When I went to the clarity aloft set I got the radio set great for me, but put another person with a different headset in and they couldn't hear me at all.

[sport65]

I think you have it. No noise for TX or RX, until it fails. Then I get a slight change in side tone when it fails when transmitting, no sound at all for RX. I tried lots of different filter and noise settings on the first radio trying to fix it. I believe I tried everything for radio settings on the first radio. Since it has done the same thing with the second radio from MGL, I have not tried going through all the setting again. Hopefully this DC filter and or resistor spark plugs I'm getting will fix this.

[edclee]

I had the same problem with my V6 in my Corvair powered Sonex. It would work fine on an external battery in flight or otherwise. It would work fine with engine not running. After some period of operation however it would seem to not work and there was no display indication it was not working. One time this happened, I heard a transmission from someone, sounded like an airliner. I realized that the radio WAS working but it was on a frequency not shown on the display. I was neither receiving or transmitting on the displayed frequency. I set up an experiment and waited until it "quit" working, then used a scanner and trransmitted. It took a long time but I finally found that I could hear my transmitted sound on a weird frequency. I tried this numerous times and discovered that the radio was transmitting and receiving on random frequencies NOT the selected frequency. MGL sent me a replacement radio and it did the same thing, so not something with my specific radio. I got two clip-on ferrites and put ALL the wires going to the radio through the two ferrites (i could only get one full turn through them due to wire sizes). This has solved the problem for the last 300 hours. I think the problem is actually a ground loop caused by the ground to my headset connections (since the phone and mike jacks are grounded to the airframe). There is no practical alternative to this however. The radio has the ability to be remotely tuned by CAN bus and I think the bus "sees" input from the noise level and interprets it as a frequency change command.
Ed Lee
Sonex 1212
120 hp Corvair

[sport65]

Thanks Ed! I did put all the wires through one ferrite bead( only had one at the time), which did not fix it. I now have two ferrite beads with fifteen wraps total but just on power and ground. I have two more clip on ferrite beads. Are you saying you think the "loop" is coming through the can wires from the efis ? I can try putting the ferrite beads on the efis can wires then.

[lpaaruule]

I happened to see this DC - DC regulator while surfing around. One of the reviewers used this in his Rotax powerd plane with Xcom radio issues. He said his radio works great now. Though the reason he thinks it resolved the issued may be flawed, I might try it on mine to see if I get less noise while engine is running.

https://amzn.to/2Ei9xxR]https://www.amazon.com/Voltage-Stabilizer-Protector-Regulator-DC10-36V/dp/B06Y5JHZG2/ref=sxbs_sxwds-stvp?keywords=isolated+12v+dc+to+12v+dc+conditioner&pd_rd_i=B06Y5JHZG2&pd_rd_r=49797575-c29c-4eb3-8d5c-164ee869cc0f&pd_rd_w=Hk0Yw&pd_rd_wg=kOLkK&pf_rd_p=2bf9af0f-7ac2-4b4e-92dd-760e99577daa&pf_rd_r=8S6K3V9768KQDXZZF0JP&qid=1547994505

A little more looking, and I found this model: RSD-60G-12. It's made for harsh environments, it's isolated, and can supply 5A. Digikey sells it for $37.
https://www.digikey.com/products/en?key ... RSD-60G-12

[sport65]

Thanks Paul, I appreciate the ideas. I already have this filter I'm going to install, hopefully at the beginning of the week ( https://lonestaraviation.com/product/fa ... 16fd43adaa ). The price on yours is better.
Because my resistor spark plugs are backordered, I'll see if the DC filter fixes it first. Update coming !

[sport65]

The DC filter seems to have solved the issue. Unless it is somehow intermittent now, the radio has worked fine for the last two flights with just the filter added. Nobody has responded with the newer generation Jabiru 3300 (gen 3 or newer), so I guess it is an issue with the newer engine. Thanks for the help and advise everyone