GTN 750 froze up!

N747JB

N747JB

Final Approach
Joined
Jul 10, 2011
Messages
6,248
Location
Atlanta
Display Name
Display name:
John
I was flying home this morning from Destin, when ATL approach cleared for the visual to FTY, I couldn't get the radio to switch frequencies! I already had the tower in standby, but no amount of pushing on the faceplate would make it switch. Since I'm a resourceful guy, I dialed the tower into my #2, but since my audio panel is remote and is controlled through the 750, no luck. Approach coordinated with the tower and I was cleared to land. Taxiing to the FBO, I shut down the 750 and turned it back on, it was fine. Anyone else have this happen? I thought I had something on my hands, I tried using my phone cover, I cleaned the screen, nothing seemed to work, except restarting it.
 
Good stuff. I'm getting less exited about computers in airplanes. I was starting a turbine a few weeks ago and one of the batteries said FU shortly after the engine lit off. As I was shutting off the fuel everything electrical in the cockpit went dark...... including the MVP-50 that displayed all of the engine gauges. I had no idea what the peak itt was during the start attempt. We checked the data log and every recorded parameter was shown as the highest number the box would display. I was pretty sure the oil temperature didn't reach 999 degrees. Ended up having the engine borescoped to inspect for overtemp condition. All because I didn't have a regular old round gauge to show itt.

To address your specific issue I would reach out to Garmin. If they don't know about service difficulties they can't fix them. I have had many instances of technology doing wired stuff in airplanes. Your 750 isn't special.
 
The remote audio panel bit is interesting, I'd not thought about it before but it's key to the redundant systems concept, and if it's built into or controlled by one of the systems that's an issue.

I know it wasn't the failure mode here, but which COM does your audio "panel" failsafe to?
 
CMongoose said:
The remote audio panel bit is interesting, I'd not thought about it before but it's key to the redundant systems concept, and if it's built into or controlled by one of the systems that's an issue.

I know it wasn't the failure mode here, but which COM does your audio "panel" failsafe to?
Click to expand...
I believe turning the number one off would have resulted in the number 2 radio becoming active. But, I'm going to dig into it more next week.
 
This is a perfect example why I don't want a huge screen EFIS controlling everything in the plane as seems to be the trend in the experimental world these days.
 
I've been thinking about a new car...I definitely do not want the touch panel that controls the radio, ac/heat and everything else. Hate them.
 
Yes, I've never been a fan of touchscreen. Even on my phone, I still wish I still had my old Blackberry with the actual keys on it. Comm 1 on the plane I fly at the club is a gtn750, the other are the old school instruments, and frankly I use the old school instruments more often than the gtn, especially if I have Foreflight with me.

About cars, many people hate the BMW idrive center rotary knob but I far prefer it to the touchscreen we had on the Altima and what I find on rentals
 
murphey said:
I've been thinking about a new car...I definitely do not want the touch panel that controls the radio, ac/heat and everything else. Hate them.
Click to expand...
Sorry to disappoint, but for most newer models, that's the trend.
 
As I reported at the time, my 750 completely died on me in IMC last year. With no warning the screen suddenly went dark and all functions instantly stopped, both nav and comm. Recycling power made no change.
Fortunately my destination was VFR so it was a non-event otherwise.
Turned out it was a "motherboard failure" in the 750 that Garmin claimed they had never seen before. The unit was a couple of months out of warranty, but they gave me a 50% discount on the steep repair fee. It's been working fine since.
 
A dual panel system is redundant. PFD/MFD has a reversionary mode in the G1000 for example. Add to that redundant AHRS and ADCs and this scenario would be nearly impossible to experience. But it sounds like a hardware glitch. The OP should have an avionics shop run a diagnostic on it before flying again.
 
From the GTN 725-750 Cockpit Reference Guide


"Remove power from the GMA 35 audio panel by pulling the circuit breaker labeled “Audio.” The pilot will be able to communicate with the Com 2 radio. Contact dealer for service."
 
Plano Pilot said:
From the GTN 725-750 Cockpit Reference Guide


"Remove power from the GMA 35 audio panel by pulling the circuit breaker labeled “Audio.” The pilot will be able to communicate with the Com 2 radio. Contact dealer for service."
Click to expand...
Thanks!!
 
RotorDude said:
As I reported at the time, my 750 completely died on me in IMC last year. With no warning the screen suddenly went dark and all functions instantly stopped, both nav and comm. Recycling power made no change.
Fortunately my destination was VFR so it was a non-event otherwise.
Turned out it was a "motherboard failure" in the 750 that Garmin claimed they had never seen before. The unit was a couple of months out of warranty, but they gave me a 50% discount on the steep repair fee. It's been working fine since.
Click to expand...
I'm sure it's out of warranty, I think it's been 4 years since my install. I don't think I've ever had an issue with my Garmin products before.
 
Tarheelpilot said:
Good stuff. I'm getting less exited about computers in airplanes. I was starting a turbine a few weeks ago and one of the batteries said FU shortly after the engine lit off. As I was shutting off the fuel everything electrical in the cockpit went dark...... including the MVP-50 that displayed all of the engine gauges. I had no idea what the peak itt was during the start attempt. We checked the data log and every recorded parameter was shown as the highest number the box would display. I was pretty sure the oil temperature didn't reach 999 degrees. Ended up having the engine borescoped to inspect for overtemp condition. All because I didn't have a regular old round gauge to show itt.

To address your specific issue I would reach out to Garmin. If they don't know about service difficulties they can't fix them. I have had many instances of technology doing wired stuff in airplanes. Your 750 isn't special.
Click to expand...

Hi!!! are you referring to the EC120, I just got one a month ago , and its very demanding on the battery, it could show 24,8v but as you crank it, it could drop dramaticaly below 17 or even 15v, and then the screens go out, and it registers all sort of message at the top of the range, we need a battery that keeps its cranking power......or else....
how do you enjoy the EC120????
 
that the reason I choose the KSN770 , its an hybrid, both touch and knobs, and I kept the old Bendix gauges, I refused to go full screen, The Avydine on a Cirrus quit twice when I was getting checked, it gave me a very strong lesson....
j-p
 
j-p said:
that the reason I choose the KSN770 , its an hybrid, both touch and knobs, and I kept the old Bendix gauges, I refused to go full screen, The Avydine on a Cirrus quit twice when I was getting checked, it gave me a very strong lesson....
j-p
Click to expand...

Are you saying that touch screen increases risk of lockup? I'm not seeing any direct corrolation. I've had a TSO aircraft GPS that would randomly reboot by itself, built long before touch screens existed.

A side note, if it locks up, freezes or goes blank how does extra knobs & buttons make it better? They are both useless at that point...

As far as the GTN series goes, they need to be installed on a circuit breaker that can be manually tripped and reset IMHO. My reasoning is they have no built-in power switch. Thats great because I'll never have to send the radio in for service because the power switch broke when it doesn't have one. Breakers are "cheap" (er than a garmin repair) so I swapped the old breakers for new ones that can be manually tripped.

That all being said, I don't like the idea of remote mounting the audio panel, but had the OP remembered the failure modes and solutions in the cockpit reference guide the situation would have been a lot less exciting.
 
Last edited:
not really what I wanted to express, but in a way, its more limited, and its Garmin, so it needs to be sent away for repair
I preferred Bendix since its hybrid , and never really like full touch screen anything,
and Bendix can be repaired locally
but I understand its changing, they to, advised their dealers that they will no longer be allowed to repair locally
bummer,
 
You must log in or register to reply here.
Back
Top