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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..
 
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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.
 
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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;)
 
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Lighting Bus Wiring Information

supik said:
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..
Click to expand...

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
 
Walt said:
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.
Click to expand...

That's one of the options on my table; I was however looking for an easier solution before I start rewiring..
 
g3xpert said:
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
Click to expand...

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

supik said:
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,
Click to expand...

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
 
g3xpert said:
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
Click to expand...

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

thanks,
 
Has anyone else had the problem of the GMA being too dim or have a solution? I have a GMA 245 and it is very dim compared to the other Garmin units. Even on just the photocells.
If I put just the GMA on the lighting bus, set it to the brightest setting, it is still dimmer than the other units when it is very dark and the other units are on photocell.IMG_0360.jpegIMG_0362.jpegIMG_0363.jpeg
 
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This subject has been brought up enough on other forums for me to believe there is no easy solution to this problem. I can either, (1) use a separate output on the lighting control unit that I planned on using for a different purpose. In which case the setting will probably be at max brightness at all times. So option (2) is power the GMA light bus with 14v constantly. Even at full brightness it will not be brighter than the other units at their full dim. Option (3) is make a separate rheostat just to control the GMA but again it would probably just remain in the full bright position.
This will only somewhat fix the lighting for the text. The annunciator lights are independent and always controlled by the photocell so they will be very dim in low light situations.
It is disappointing that Garmin couldn’t maintain a certain level of consistency with this.
 
I too experience this. Luckily I know where the 4 usual buttons are that I need to push. haha It is definitely dim though...
 
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