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Navman chartplotter screen v v dark


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#1 Prawn

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Posted 08 November 2017 - 04:31 PM

After several months on the hard stand I tried using our Navman 6500 after launching and can barely see the screen it's so dark.  I've fiddled around with the settings - straining to see the screen.

 

Either I'm doing something wrong - I hope - or I have to 'Bring Out Another Thousand' to get a new Navman equivalent.

 

Once on, I've pushed the start button twice quickly.  This brings up the 'Backlight' set at '15' - using the arrow keys I can't increase it, but if I try decreasing it the screen is totally blacked out.  So presumably this is the maximum setting? The 'Night' mode check box is unticked.  I then checked the 'Palette' set up which was set to 'Sunlight'  and being hopeful switched it to 'Normal' but it made no apparent difference.  Is there something else I can do??

 

 

 

 

 


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#2 wheels

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Posted 08 November 2017 - 05:13 PM

Hmmm, it sounds like the Backlight/s may not be working. Which would not be easily repairable, if at all.


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#3 slanty

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Posted 09 November 2017 - 06:22 AM

I had this happen. it is the backlight. Difficult to know whether its the little flourescent tube or the driver that has failed, and you don't know until you replace both unless you can test with an oscilloscope, and even then it's not super easy to diagnose.

 

I replaced mine with an led backlight but you lose control of the brightness via the software and the repair in my case at least looks very home brew - I've probably lost waterproofness in the unit for one but it suits me for the moment.  


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#4 Steve Pope

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Posted 09 November 2017 - 07:05 AM

I have a NavMan that the screen goes dark on after a shortish time when exposed to sunlight. It is a fault with a (I think Diode) in the unit, it was fixed by NavMan by replacing the unit, not fixing it, (cheaper?) The one I have was replaced 3 times before they disappeared off the market. I made a sunshade for mine that keeps direct sunlight off it. So far So Good.


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#5 jonathan

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Posted 09 November 2017 - 07:10 AM

remembering the three NM units replaced under warranty on RnB back in the day.....


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#6 Prawn

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Posted 09 November 2017 - 07:26 AM

Thanks All, sounds like it could be a number of technical things:  backlights, drivers, diodes and I've read on the internet, inverters.  We've taken it apart and have taken a punt and assumed it's the CCFL backlight so will order one from the US. Surprisingly found one the right size and L shape!

 

Only thing is 3 ?plasticy sheets the size of the screen slipped out from behind the mechanism and we're not sure what order they should be in the re-assemble....Anyone know what those are for/and order?

 

Cheers.


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#7 wheels

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Posted 09 November 2017 - 11:27 AM

They are two diffusers and a lens to make the backlight even over the screen area. There are dozens of types and scenarios of ways around. If you have it wrong, you will tend to get a bright and dull area in the screen. Usually the scenario is a white filter, a lens and a diffuser. If it the light does not look even over the screen, try them another way around.
So it's a mini fluro tube? The modern day units use LED's. But there are two different ways they can be fitted. Along the screen edge. The screen has a weird pattern on the back surface to refract the light through. they use a pure white filter on the back and usually nothing else. The units that have the light directly behind the screen, usually have the Lens first. Then the diffuser, then the filter.

You can get parts?
Do be aware that these units came pressure filled with nitrogen to stop moisture getting in. Nothing you can do about that now you have opened it. Shouldn't matter too much.
 


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#8 slanty

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Posted 09 November 2017 - 11:54 AM

Just be aware that replacing the ccfl might not be the issue as the inverter (driver) is often the issue


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#9 wheels

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Posted 09 November 2017 - 04:11 PM

Or both. The fluro failing can cause the inverter to fail due to no load.


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#10 Prawn

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Posted 10 November 2017 - 01:42 PM

So we've already compromised the Nitrogen water proofing!  Interesting to know.  And our replacement backlight might not work....and then it'll be just a learning exercise...

 

We've ordered the tube from ccflwarehouse.com   They are made in the US and supposedly good quality.  Relatively cheap - the biggest cost being the postage but we're keeping that lower by having it posted to a US address and then on posted to us. Also saw a UK site.  


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