Phalaenopsis leaf problems

[An_DS]

Two of my Phalaenopsis keep having a leaf problem and I'm really thinking about throwing them out.
What happens: a new leaf pops up fine, after a while it starts de decolor and eventually dead parts can be seen. These 2 fellows did flower and struggle to survive. It definately ain't sunburn or cold damage.
It's not contagious. I really wonder if it ain't Cymbidium Mosaic Virus or ORSV or a combination. I have got Cymbidium as well, in another thread I'll post some pictures of them, I have one on my suspicious-list!
The last picture is a nearby Phalaenopsis, which seems te have something similar, but not as serious. Perhaps another cause there (mites).
What do you think?