[Texasrocker]

.... check all orig factory solder connections point-to-point. A cold solder joint could cause this, especially in a band-switch, tube socket-pin connection(s), or the chassis' antenna-coils solder connections. While the set is in operation, wiggle and tap on the tubes also. If you find any intermittent-prob there, and reception improves, bingo. Also, double-check your antenna connections. If your set has the dreaded- loctal type tubes also,(most probably?) most likely you have a dirty pin-connection somewhere on tube pins. These type tubes& sockets pins are infamous for bad connections also. Scrape the loctals tubes pins connections "shiny-clean" with a exacto knife. Just quick-guessing here, tryin to help. If it has pushbuttons tuning, check for clean contacts there also.