Coincidence???

[MikeOH]

I've owned my M20F for two years and have not had any avionics problems...until the last month.

On a recent flight my G3 Insight engine monitor 'froze' with a random pattern on the screen.  I was IFR and did not want to cycle power during flight.  After landing the G3 reset after cycling power and has been fine ever since.

However, the next morning, the GNS430W was dead, and no amount of cycling power changed that.  It took $1200 and a trip to Garmin (see my "Black screen of death" thread).

Now, the PM1000ii intercom is dead.  It may have failed on the trip above because it 'fails safe' to pass through and it was my wife that noticed on our last flight that she could barely hear.  No response from the volume or squelch controls, but unit is receiving power.

This looks all the world like a serious over voltage event occurred, but I have ZERO idea what would have caused it.  The G3 data showed a stable 13.8 Volts right up until the unit 'froze'...and, has shown the same since.

Obviously, I'm concerned about this happening again.  Unless, this was just coincidence.

Anyone ever had something like this happen?  I'm at a loss for troubleshooting ideas as this appears to be the mother of an intermittent: a single event.

Now living in fear that this will happen again...

[carusoam]

Can you download the history off the G3?

If a power surge occurred... it probably has something in its saved history...

Sending the data over to savvy and graphing it will make the review process a whole lot more simple than actual reviewing numbers...

PP thoughts only, not a mathematician/numbers guy...

Best regards,

-a-

[DXB]

30 minutes ago, MikeOH said:

I've owned my M20F for two years and have not had any avionics problems...until the last month.

On a recent flight my G3 Insight engine monitor 'froze' with a random pattern on the screen.  I was IFR and did not want to cycle power during flight.  After landing the G3 reset after cycling power and has been fine ever since.

However, the next morning, the GNS430W was dead, and no amount of cycling power changed that.  It took $1200 and a trip to Garmin (see my "Black screen of death" thread).

Now, the PM1000ii intercom is dead.  It may have failed on the trip above because it 'fails safe' to pass through and it was my wife that noticed on our last flight that she could barely hear.  No response from the volume or squelch controls, but unit is receiving power.

This looks all the world like a serious over voltage event occurred, but I have ZERO idea what would have caused it.  The G3 data showed a stable 13.8 Volts right up until the unit 'froze'...and, has shown the same since.

Obviously, I'm concerned about this happening again.  Unless, this was just coincidence.

Anyone ever had something like this happen?  I'm at a loss for troubleshooting ideas as this appears to be the mother of an intermittent: a single event.

Now living in fear that this will happen again...

Sorry for these costly events - seems very unlikely to be coincidence.  I would be afraid to fly again until someone with real electrical expertise checks the systems. The risk of more fried components and maybe even an electrical fire in flight  seem to justify the effort and expense.   Could a low sampling rate on the G3 be missing the destructive voltage spikes?  Could this be a runaway alternator? A malfunctioning voltage regulator? Have there been any popped CBs?

[MikeOH]

1 hour ago, carusoam said:

Can you download the history off the G3?

If a power surge occurred... it probably has something in its saved history...

Sending the data over to savvy and graphing it will make the review process a whole lot more simple than actual reviewing numbers...

 

1 hour ago, MikeOH said:

... The G3 data showed a stable 13.8 Volts right up until the unit 'froze'...and, has shown the same since....

So, yeah, I can and I did.

[carusoam]

Did you want to share the savvy link to the data?

We have some engineers and other people around here that can look at the data...

Sometimes they see things that others might not...

And of course... Savvy has a service to review the data professionally...

Three devices failing in a short period of time... doesn’t sound very random...

I can understand an intercom and a radio having a similar challenge... what could bring the engine monitor into the same challenge?

Best regards,

-a-

[MikeOH]

1 hour ago, DXB said:

Sorry for these costly events - seems very unlikely to be coincidence.  I would be afraid to fly again until someone with real electrical expertise checks the systems. The risk of more fried components and maybe even an electrical fire in flight  seem to justify the effort and expense.   Could a low sampling rate on the G3 be missing the destructive voltage spikes?  Could this be a runaway alternator? A malfunctioning voltage regulator? Have there been any popped CBs?

Well, I have been flying since with no issues.  And, I have pulled the G3 data with no anomalies seen.  G3 is at its highest sampling rate, but that's not going to capture micro, or even milli, second transients.

Never any popped CBs, or over-voltage indication.  Absent that, I'm not concerned with fire, but with more failed avionics.

While I appreciate the suggestion, taking it to a shop with NO presenting symptoms sounds like a great way to spend hundreds, or thousands, of dollars looking for ghosts.  I am a practicing EE, so it's not like I have no background. But, yes, some intermittent in the VR/alternator system would seem plausible; was hoping someone here had seen and fixed the same kind of problem.

I brought up this over-voltage theory with the avionics shop I took the blown GN430W to, and the owner seemed to think that was HIGHLY unlikely as the WAAS models are universal input (switch-mode power supply) good up to something like 40 volts.

Anyone know what voltage an alternator can reach?  Also, isn't there an overvoltage 'clamp' in the system?

[moontownMooney]

Any chance you could have cabin heat duct that has come off a fitting or worn through, bathing the avionics in exceedingly hot air? I dont know if the air is really hot enough to do this (it is pretty freaking hot) but it is a failure mode that could suddenly affect all your avionics and obviously without leaving an electrical supply failure trace.

Sent from my LM-V405 using Tapatalk

[MikeOH]

1 minute ago, moontownMooney said:

Any chance you could have cabin heat duct that has come off a fitting or worn through, bathing the avionics in exceedingly hot air? I dont know if the air is really hot enough to do this (it is pretty freaking hot) but it is a failure mode that could suddenly affect all your avionics and obviously without leaving an electrical supply failure trace.

Sent from my LM-V405 using Tapatalk
 

Thank you!

That's the kind of 'out-of-the-box' idea I was hoping for.  I'll check that out.

[DXB]

2 minutes ago, MikeOH said:

While I appreciate the suggestion, taking it to a shop with NO presenting symptoms sounds like a great way to spend hundreds, or thousands, of dollars looking for ghosts.  I am a practicing EE, so it's not like I have no background.

Completely fair point! And it turns out your background leaves you already far better equipped to ferret the problem out than me (or most A&Ps for that matter).  I'll be curious what it turns out to be.

[MikeOH]

10 minutes ago, carusoam said:

Did you want to share the savvy link to the data?

We have some engineers and other people around here that can look at the data...

Sometimes they see things that others might not...

And of course... Savvy has a service to review the data professionally...

Best regards,

-a-

No reason to.

The G3's ONLY electrical system monitor is system voltage.  And, as an EE, and as previously stated, there are NO clues in the system voltage as far as what the G3 records: stable at 13.8 volts right up to the point where the G3 'froze.'  Subsequent downloads show the same stability.  If this is NOT just coincidence, then it's a transient event whose source remains a mystery.

[carusoam]

‘Like’ probably isn’t the right thing...

More of a ‘I hear ya’...‘
 

Did the Garmin experience yield any insight to what or why it failed?

 

Some instrument failures That occur around here...

Mostly voltage low... some experience high voltage... alternators stuck on/off...

Some devices are thermally protected... so if they get really hot, they shut down first...

A few have been bathed in water...

we have a few avionics shops around here... we can invite to the conversation...?

Best regards,

-a-

 

[MikeOH]

5 minutes ago, carusoam said:

‘Like’ probably isn’t the right thing...

More of a ‘I hear ya’...‘
 

Did the Garmin experience yield any insight to what or why it failed?

 

Some instrument failures That occur around here...

Mostly voltage low... some experience high voltage... alternators stuck on/off...

Some devices are thermally protected... so if they get really hot, they shut down first...

A few have been bathed in water...

we have a few avionics shops around here... we can invite to the conversation...?

Best regards,

-a-

 

What Garmin provided with the repaired unit left a LOT to be desired.  In it's entirety:  "Verified problem. Replaced main board and display lens. Tested and met all specifications."  Pretty disappointed.

Never flown in rain. Never washed with water (use Wash-Wax-All).

Yuup.  I'm hoping one of the avionics guys here will see this thread and take pity on me

[carusoam]

Let’s see if anyone we may know is around...

inviting @Baker Avionics @Jesse Saint unique Avionics challenge question...
 

I would include @TrekLawler if he happens by...

Best regards,

-a-

 

[Baker Avionics]

On 10/27/2019 at 2:57 PM, carusoam said:

Let’s see if anyone we may know is around...

inviting @Baker Avionics @Jesse Saint unique Avionics challenge question...
 

I would include @TrekLawler if he happens by...

Best regards,

-a-

 

Well, all I will say is there is a reason why I am not a fan of Garmin, LOL.  Aside from that, it seems like you may have had a ground issue or maybe a bus issue.  Now, IF there was a "surge" would it be evident in everything that has power to it?  Mags, Lights, switches, CBs, etc....is everything working now?  Was it mainly things on the Avionics Bus and nothing on the battery bus?  Those are the anomalies that need answered and explained to go any further.  Did anything else "burn up?  Were all of thiose units hooked to the same grounding point and there is an issue there?  

 

Inquiring minds want to know!!!!!

[MikeOH]

Hi Greg,

Thanks for responding!

Yes, at the moment, everything is working (except for the intercom that I haven't yet replaced/fixed).  The Garmin, G3, and intercom are all on the CB switched Avionics buss.  Nothing else has burned up....so, far.

I have no idea if those items share a single point ground...and, no idea how to track that down...many wires, all white, bundled together, buried behind the panel and, I'm not sure my back is up to the task

Does the electrical system have any (effective) overvoltage protection system?  Probably well before the days of transorbs and the like, but curious if the system is 'clamped' at some voltage.  What kind of spike could occur with a temporary VR/alternator failure?

Thank you!

[chriscalandro]

Each device should have some kind of protection, as an EE the only things I can come up with are coincidence, or maybe when the intercom died it send some garbage through the bus.

Everything should be protected against spikes, at least at the price point of these devices I'd certainly hope there was a good amount of filtering.

 

When it comes to Mags, Lights, switches, CBs and a surge being evident -

no, except maybe lights, but i'd guess it would be too fast to be noticeable.  CBs work based if current, not voltage.  A voltage spike will not pop breakers.

 

[takair]

Is it possible the audio panel was failed for a time prior?  You mentioned it was your wife who pointed it out.  I fly alone often, so things related to other seating positions can go un-noticed.  I have seen the G3 do that in a students plane, twice.....and I have had random 430 failures..more than once.  You may just be having a string of bad luck....and if bad luck comes in threes, you may be done.  Might be worth checking the common avionics and panel grounds, would be remote for it to take out three different systems, but bad grounds in Mooney installs can occur.  

[MikeOH]

Yes, quite possible the intercom was out for some time prior.  If I'm not having a squelch problem I don't touch it.

Honestly, I'm hoping it's just a string of bad luck.  Much preferable to tracking down intermittent electrical issues in a 50 year old aircraft!

I'll crawl under the panel and see if I can ID some common ground points and check their integrity.  Beyond that, I'm going to take a 'wait and see' approach absent any other suggestions.

Thanks, all

[whiskytango]

Is it possible that your plane was energized by lightning while on the ground?  Lightning can do highly unpredictable things to electronics, even if the avionics master is off. 

[NotarPilot]

Electrical issues are a PITA to diagnose and track down.  I’m experiencing an issue when my number 2 IFD 440 transmits intermittently. I swapped boxes and the issue stays at the bottom so it’s a wiring issue. I had an avionics guy work on it and it seemed to be RF in the wiring. He fixed it by separating some bundled wires and that fixed it for a while. Happened again, he worked on it again and briefly fixed it and the problem returned.  He doesn’t know what else to do and it’s frustrating as hell.

I also have a G3. I like it but it does some weird things sometimes too.  A few weeks ago the fuel flow read 0.0 after start up. I cycled it off and on and it worked fine.  I’ve probably sent it in 2 or 3 times back to Insight for repairs after it did weird stuff since owning it.  Support has been great by Insight but I’m not sure I’d buy one again. I’d probably look at the CG-30.  Anyways, good luck with your diagnosis. I definitely feel your pain. 

Edited November 6, 2019 by NotarPilot

[Bolter]

As a proactive thing, if you do not already have an updated modern voltage regulator (ex. Zeftronics), that is a relatively low cost upgrade that may help protect the system.  

-dan

[MikeOH]

4 hours ago, Dan at S43 said:

As a proactive thing, if you do not already have an updated modern voltage regulator (ex. Zeftronics), that is a relatively low cost upgrade that may help protect the system.  

-dan

I'm pretty sure I do; I'll check next time I go the hangar.

Thanks for the suggestion!

[larryb]

Electrical issues are a PITA to diagnose and track down.  I’m experiencing an issue when my number 2 IFD 440 transmits intermittently. I swapped boxes and the issue stays at the bottom so it’s a wiring issue.

Could also be the audio panel. Or the audio panel tray connector.

[NotarPilot]

5 hours ago, larryb said:

 

Could also be the audio panel. Or the audio panel tray connector.

 

I thought the same thing but I pulled the audio panel CB in flight to turn it off and it continued to do it.  Also, another weird thing happened last week, I pulled the number 1 IFD 440 CB to see what happened and that only caused the intermittent TX problem to go steady TX.  Tried it twice with the same results.  Anyone have an idea on what might cause that?

[carusoam]

The way the PTT switch works is by grounding things...  the PTT closes(?) a ground...

Sounds like something is getting grounded accidentally and then permanently by the various actions described... 

Checking a wiring diagram for the devices may be helpful to your trouble shooting process...

Sound familiar?

PP thoughts only...

Best regards,

-a-