Well, it seems the tuneable IF section, 2 to 3 megs is working, the loop section, ie, megacycle selector is working, so the money goes on the second mixer back. This is a juncton FET, it may be open. There is little to go wrong with the 55 meg first IF section, there is a dual gate FET in there, that never gives problems, neither does the front end balanced mixer. So, i would check the second mixer, just replacing it is easy and cheap? and will eliminate that one.
