If you have an old HP-23 that you needs work (e.g. capacitor replacement) and you desired to use on the KMW-2, you could update it. The Heathkit shop has a new regulator board (HP-23R) that has optional regulation of the screen voltage when used with Collins equipment. http://www.theheathkitshop.com/hp23r.html This idea and design was based on earlier notes from a Collins reflector list. Greg w9gb