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G3X GDU460 MFD - inflight reboots and freeze

maus92

Well Known Member
Today I was out testing a complex flight plan with ~60 waypoints for a project. The flight took place at 1,000' over a local river, and I had flown a similar pattern the day before. About midway through, I noticed that the GDL-39R traffic page on the PFD said "Traffic Coasting," then the MFD rebooted. The MFD ran for another minute or so, then I got a message that the VP-X had lost comm with the PFD. Then my radio X'ed out. Then some other EIS instruments X'ed out. Then the transponder X'ed out. However, the radio was still receiving the nearby tower comms, and the autopilot was following the flight plan perfectly. The radio freq box came back. Then the MFD rebooted again. I decided to call it quits for the day and head back home, and called the tower. Thankfully they heard, and confirmed the transponder was working. On the way back, the MFD rebooted again, then froze. I entered the pattern, and on final, the MFD rebooted again and seemed to be working for the short time between landing and getting back to the shed.

I called Garmin after I pushed back into the hangar, and spoke to one of the reps - not sure if he was an G3X guy, or a general support person even though I was calling the EXP line. Basically I explained the problem, then he asked if I had the latest software - which I thought I did - 8.3. Nope, new version 8.4 just came out to fix some issue they were having. He also suggested not having SD cards in the slots because that has been causing some rebooting apparently (I use SD cards to record flight data and screenshots, and load fpls.) If these steps don't fix the problem, I was told to send in the unit for an exchange for $350.

1. Obviously I will update the software.

2. I will only keep an SD card in the PFD (not both as I had today.)

3. I don't want to send in the MFD until more troubleshooting is performed.


I had a similar problem with this MFD two summers ago (although not particularly hot over the mountains at the time,) but it came back after rebooting. I'm wondering if this might be a temperature issue. It was pretty hot in the cockpit at 1000 ft and a bubble canopy, and the G3X screens get pretty hot all on their own. On the last go around, Garmin asked me to download a file from the unit and send it to them - no such request this time. Anybody have other suggestions?

Thanks,

Charley

Attaching a pic for your amusement (not sure it will work though.)

https://share.icloud.com/photos/0eMpyaAhSCLu9GPP6TyRFTzoQ
 
Hello Charley,

Please contact us via the email shown below. We are happy to work through this issue with you. We would definitely like to collect the diagnostic information.

There is no problem with using a SD card for flight data logging in both GDU units, but it is always best to only use those cards for flight data logging (no software or databases).

We have never seen a heat related issue in a GDU 4XX. The single cooling fan is almost not needed and hardly ever runs.

Thanks,
Steve
 
Give some thought to checking the wires in the connector. There is a decent chance that the power or ground pin, or perhaps something ground related is not fully connected and intermittent. Voltage spikes from an intermittent connection cause all sorts of weird problems. Soldered and crimped line connections bear checking too; soldered most of all. Can't hurt to take off the backshell, use a fine tool to pull a little on all the wires and make sure all are secure.

Also strange because a lot of what you lost is serial connected. Would be interesting to swap the PFD/MFD and see what problems move. Any chance the serial connections are to the MFD and the CAN bus sends them over to the PFD? So when the MFD flakes out the serial connections are lost to the PFD?
 
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Same thought, different test suggestion

Give some thought to checking the wires in the connector. There is a decent chance that the power or ground pin, or perhaps something ground related is not fully connected and intermittent. Voltage spikes from an intermittent connection cause all sorts of weird problems. Soldered and crimped line connections bear checking too; soldered most of all. Can't hurt to take off the backshell, use a fine tool to pull a little on all the wires and make sure all are secure.

Also strange because a lot of what you lost is serial connected. Would be interesting to swap the PFD/MFD and see what problems move. Any chance the serial connections are to the MFD and the CAN bus sends them over to the PFD? So when the MFD flakes out the serial connections are lost to the PFD?

You don't have to remove the back shell and pull, just take a 3/32" punch (or similar) and push on the tip of the pins in the connector. If not latched, they will likely already be recessed from the others, but will easily move. I found more than 3 in my harness this way and much easier and less risk than pulling on wires from the back.

Edit: From post #5 : Good point, only for poorly seated pins.
 
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A quick update. Steve from Garmin requested I send diagnostic files from the GDUs, which I did.

I have yet to check the pins, but is certainly a good idea. Another datapoint is between the reboots, the MFD reacted very slowly to knob twists to change pages. Also, voice announcements from the system were very slow: not the words themselves, but the time between words were drawn out. When the screen rebooted and froze, I was getting almost continuous verbal announcements (but I guess I did a good job of zoning those out because I can't remember what they were saying.)
 
Also another note about SD cards left in the displays. It's OK to do so, but they should not include update files. So I will insure the cards I use only contain log files, screenshots and flight plans.
 
Note about the main connector. On the GDU460, the connector half with the male pins is mounted on the GDU. All pins in the three rows appear straight and solid. The connector mounted to the wiring harness luckily has a relative few active connections. I checked each socket to make sure the female pin was firmly in place, and and opened the shell to make sure the wires were still connected to the pins. Everything looked OK. When the system is powered on in the hangar, everything works as advertised, although the MFD doesn't seem to retain accurate time (without GPS signal) yet the PFD does, and the MFD is slow to recognize SD card insertions.
 
After working with TeamX over several weeks, they concluded the root cause of my issue(s) was a SD card reader failure. The display did not crash if a SD card was not inserted, however the situation deteriorated last week when I could no longer perform database updates. I installed a replacement GDU and flew yesterday with no issues. The SD card was recognized instantly, and no reboots. A side benefit was the internal clock now retains system time between power cycles.

Thanks to TeamX for resolving the issue, although my wallet did suffer the standard exchange fee ;)
 
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Was this out of warranty ? What exchange fee are you referring to?

The G3X Touch was purchased in December 2014, and installed and flying in 2015 - so yes, the warranty had expired. I was hoping Garmin would take pity on me since several people have had SD card reader failures that cause reboots, but no dice. Garmin charges a flat exchange fee for repair - at least for displays. The good thing is you get a refurbished unit right away; the bad thing is you might be inheriting someone else's problem... I haven't really had good luck with refirbed electronics, so we'll see.
 
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