I started refinishing/and recapping a RCA 9K1 in March of 2022, and just finished it up Sept 2023. I had replaced a couple of tubes too, and I did my own alignment with an RF signal generator and schematic about 8 months ago. However, upon finishing things up just recently, I have found that I have low volume, poor sensitivity, and the Magic Eye/Tuning tube is not moving. I found that the 6H6 2nd Detector/AVC tube was showing ‘short’ on my Mercury tube tester, so I replaced it. I plugged it in, and it worked perfectly, good volume, good receive sensitivity, and Magic Eye worked! But only for 5 minutes! And then it went back to low volume, poor sensitivity. I am wondering if my replacement 6H6 tube went bad (the replacement still tests good), or if there is another problem? Anyone with experience with these have any suggestions? Ron/Regina
Edit: 2023 Oct 22 Just re-tested all of the tubes today, and found that one of the two 6K7’s was cold dead! I guess the filament/heater must have recently gone open (the dead one was in the RF stage; the remaining good one the IF stage). I’m surprised it picked up any stations; that must be why I only could get a couple of strong stations. I have ordered a new 6K7 (actually will order two, and keep the other old one as a spare).
