kashurst
Well-Known Member
Last spring the backlight died on the flybridge helm plotter. So for the summer I swapped it with the inside helm unit as we rarely use the inside station, especially in the summer. I brought the faulty unit back to the UK and contacted Raymarine to get it repaired. Not good news as depending on the fault they can no longer get parts. The usual culprit apparently is the high voltage transformer coils,or high voltage converter transistors (my favourite) or the cold cathode miniature flourescents (CCFL) that create the bright white light. I took my unit apart very carefully and powered it up out of its housing and measured the high voltage output. Over 1100 V being generated and a faint flickering in the CCFL tubes. (so be careful if you try this at home, if you get hold of it by the naughty end it will hurt quite a lot).
The high voltage bit is helpfully marked DANGER. Clearly the voltage generator is working fine, so called Raymarine and asked to buy the CCFL light assembly. Unfortunately its no longer avavilable and an internet search didn't find an equivalent. It is possible to get custom units made but didn't want to go that way. Obviously I am observing class 1 clean room conditions (well nearly and it is a new bit of chip board its all siting on)
So decided to convert it to LED backlighting. Bought two flexible LED light strips from maplins, cut them in half and stuck them inside the light box inside the display assembly with double sided foam tape
Popped it all (mostly) back together again and powered it all up and voila!
Not a great photo as the Hudl camera struggled with the contrast. However that is taken outside on a cloudy september day. Should be OK in the med, if not I will double up the number of leds to get it a bit brighter. The backlight isn't perfectly even but in daylight with a human eye its hard to tell. At the moment I am running the LEDs from the main input supply via a voltage converter (boat is 28V, leds are 12v) so I can't dim them using the plotter functions. I don't have a circuit diagram for the plotter and as its all very small surface mount devices and I don't have the equipment to properly work on it, I can live without the dimmer function for now.
The high voltage bit is helpfully marked DANGER. Clearly the voltage generator is working fine, so called Raymarine and asked to buy the CCFL light assembly. Unfortunately its no longer avavilable and an internet search didn't find an equivalent. It is possible to get custom units made but didn't want to go that way. Obviously I am observing class 1 clean room conditions (well nearly and it is a new bit of chip board its all siting on)
So decided to convert it to LED backlighting. Bought two flexible LED light strips from maplins, cut them in half and stuck them inside the light box inside the display assembly with double sided foam tape
Popped it all (mostly) back together again and powered it all up and voila!
Not a great photo as the Hudl camera struggled with the contrast. However that is taken outside on a cloudy september day. Should be OK in the med, if not I will double up the number of leds to get it a bit brighter. The backlight isn't perfectly even but in daylight with a human eye its hard to tell. At the moment I am running the LEDs from the main input supply via a voltage converter (boat is 28V, leds are 12v) so I can't dim them using the plotter functions. I don't have a circuit diagram for the plotter and as its all very small surface mount devices and I don't have the equipment to properly work on it, I can live without the dimmer function for now.
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