What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

GMA345 Backlighting setup

supik

Well Known Member
Backlight of the text labels on my GMA345 are backlit by one of my lighting buses 14VDC (GAD27) which is shared across more units. With the ligting bus set at min output; the text labels on the GMA345 are too dim.

I was hoping there would be a way how to setup a min brightness on the GMA but haven't found anything in the install manual.

If I set the min lighting bus output higher it will mess up my other units' backlight settings. I would need to go with 50% lighting bus output to match the other units brightness level..

Is there any workaround?

Plus the green photocell controlled annunciators are too dim as well at night. -no offset found in the manual..
 
Last edited:
Why not just let it use the photo cell, usually works just fine for the AP.
 
Same issue on a newly installed 245. Added an external dimmer and it’s no better. Awaiting a replacement from Garmin but not optimistic after hearing that others are encountering the same issue. Any comments from the Garmin folks out there?
 
I've installed (and used to run one myself until I swapped over to the 245R) quite a few 245 and have always let them run off their built in photo cell, I have never heard a complaint.

I 'think' you may also be able dedicate one of the GAD27 outputs and adjust its slope separately but track another 'master' dimmer.
Haven't had to do that yet but I'm pretty sure that function is available.

Or just set up a voltage divider with a couple of resisters to set the lights to the intensity you like, so they are on all the time at that level.
 
Last edited:
There is an alternative if you want a simple 'buy off the shelf' solution -I've used the Flight Data Systems LC-40e dimmer unit - have a look on the web;)
 
Last edited:
Lighting Bus Wiring Information

Backlight of the text labels on my GMA345 are backlit by one of my lighting buses 14VDC (GAD27) which is shared across more units. With the ligting bus set at min output; the text labels on the GMA345 are too dim.

I was hoping there would be a way how to setup a min brightness on the GMA but haven't found anything in the install manual.

If I set the min lighting bus output higher it will mess up my other units' backlight settings. I would need to go with 50% lighting bus output to match the other units brightness level..

Is there any workaround?

Plus the green photocell controlled annunciators are too dim as well at night. -no offset found in the manual..

Do you have both pins 6 and 7 connected to the lighting bus output of the GAD 27? If it is only connected to one of them, the backlight will only be 50% of the expected brightness.

i-dWpfmhK.jpg


Thanks,

Justin
 
I've installed (and used to run one myself until I swapped over to the 245R) quite a few 245 and have always let them run off their built in photo cell, I have never heard a complaint.

I 'think' you may also be able dedicate one of the GAD27 outputs and adjust its slope separately but track another 'master' dimmer.
Haven't had to do that yet but I'm pretty sure that function is available.

Or just set up a voltage divider with a couple of resisters to set the lights to the intensity you like, so they are on all the time at that level.

That's one of the options on my table; I was however looking for an easier solution before I start rewiring..
 
Do you have both pins 6 and 7 connected to the lighting bus output of the GAD 27? If it is only connected to one of them, the backlight will only be 50% of the expected brightness.

i-dWpfmhK.jpg


Thanks,

Justin

Justin, I do confirm, it is wired according to the 14v system.

It will light up bright when at full intensity, so I guess if it wouldn't get pwr on one of the pins I would get 50% brightness at full.

thanks,
 
GMA 345 Lighting Bus

Justin, I do confirm, it is wired according to the 14v system.

It will light up bright when at full intensity, so I guess if it wouldn't get pwr on one of the pins I would get 50% brightness at full.

thanks,

Igor,

Do you mind emailing us a copy of your config file, and a brief description of the wiring you have in place for the lighting bus output from the GAD 27 to the GMA 345? We would like to replicate your setup on one of our benches.

Thanks,

Justin
 
Igor,

Do you mind emailing us a copy of your config file, and a brief description of the wiring you have in place for the lighting bus output from the GAD 27 to the GMA 345? We would like to replicate your setup on one of our benches.

Thanks,

Justin

Justin, sure I'll send the necessary info; please allow approx. 1 week for this (I can't get earlier to the airport).

thanks,
 
Back
Top