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GTN 650 screen flicker

togaflyer

Well Known Member
Sent this to Garmin after this anomaly occurred.

During my flight on Friday my GTN 650 display blacked out several times during a 3.8 hour flight. The screen would flick off for a very brief moment then back on without any flight plan data being affected. I normally operate the display on the default nave page. One time during that flight it blacked out slightly longer (not much more than one second) but it caused the autopilot to disengage from the GPS Nav mode. I immediately restored the autopilot back into GPS Nav (external) without an issue. On Sunday during my return flight, the same issue occurred. About four quick black outs events (each occurance was separate with nothing unusual to trigger the event and at various times during the flight) and again, one time the autopilot again disengage but was reengaged without issue.

This info was sent to Garmin with data from the G3X. Nothing showed up on the data, so the only option was send it in for repair for 1,200 dollars…..ouch. (It’s a four year old unit). But…… then I came across an old Garmin bulletin regarding the same issue from back in 2014. I’m wondering has anyone had this issue since loading the recent software. Waiting to hear back from Garmin regarding a possible software glitch.

SERVICE ADVISORY NO.: 1409 Rev A
Owners/Operators of Garmin GTN 6XX/7XX Units March 14, 2014
SUBJECT:
AFFECTED PRODUCTS
GTN 6XX/7XX Occasional Momentary Screen Flicker
This issue affects GTN 625/635/650 and GTN 725/750 Units with Main Software Version 3.00 through Version 5.00.
ISSUE
During normal operation, a portion of the GTN display may occasionally exhibit a momentary flicker. This can occur on any page of the GTN series unit, but does not affect the operation of the unit.
RESOLUTION
Garmin plans to correct this issue in a future software release.
 
Check the standard issues:
- Inserted fully into the tray
- Check for a loose power lead on the associated breaker (this got me once) - if good try a different breaker.

Carl
 
Pulled the unit checked wiring (both power and ground) nothing unusual. I believe if it was a power issue (power or ground) and if it loss power even for a second, the GPS would dump my flight plan. This does not happen.
 
I had some funny things happening a while back similar to yours on my 650 after a software update. Nothing showed up in the data and finally I reinstalled the older software and it worked perfectly again. Reloaded the new software (fresh download on different SD card) after a few flights and all was fine. Never a problem since.
 
Chris, Good idea. I think first I will used a fresh formatted SD and reload the current one. If that doesn’t resolve it then plane B I will load the previous software, fly with the old one and see if it still happens. If it still occurs then off to Garmin it goes.
 
I had something similar happen on my G430W. It ended up being the dimmer circuit was intermittent and not always putting out a high enough voltage for the display to be properly illuminated.

I changed some settings and the problem is gone.
 
Update…….I reloaded the (latest) software into the 650 and so far the flickering seems to have been resolved. I have some good cross country flights coming up so that will be the real test.
 
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