A good quality, professional-style scan converter probably works much better than the cheap Chinese versions.
I have used various models of Extron scan converters before in several applications with good results. Something like this:
http://www.ebay.com/itm/Extron-VSC-5...-/141576224364
Although I had to replace some of the electrolytic capacitors in a couple of model 200s and 500s that were purchased used also. (This particular auction that has already been done.)
Not a big deal though, especially if you get them nice and cheap and they just need some capacitors to power up without blinking off and on...
