New TV means a new chance of a proper and better looking fastening of adalight.
I decided to use those:
20150509_002

from: 45 degree LED mounting bracket for 12mm tricolor LEDs

and fix them with Velcro® fasteners, that have a sticky side. Here you see the TV:
20150509_001

It works very well, especially as you can easily change the spaces between individual lights.
The results:
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20150511_002

Also the arduino got a casing and is fixed like the powersupply with Velcro® tape to the TV:
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see also: Adalight