My orchids also have large scales problem.
Recently I found time and effort to fix it.
Re-potting orchids brought some joy and some problems - some of them almost have to roots.
At least I started to number them and make records.
Phalaenopsis orchid #5 is big, with huge green leaves and no roots,
The weather is wet and humidity in room is 50%, temp +19C. I think it is low for sick orchids.
I added warm water to the bottom of the tank, put a mug with boiling water, misted the moss with warm water, added clear plastic sheet on the top with 2 lamps - one daylight and one - regular to add warms.
The temp and humidity are starting to rise.
84% ans 21C