I have been working on & off my own Heathkit HW-12A transceiver for several months. I isolated the problem to a RF Plate Choke, and replaced it with a same value new one; HOWEVER, it still would not work. I purchased this unit to extract the original manufactured Heathkit RF Plate Choke and install it in my HW-12A. I fixed the problem and now I can move on. You can never go wrong using original parts, if you can get them...