Quote:
Originally Posted by Kamakiri
...I get low volume no matter how high I turn it up, but I can flick the radio on and off quickly and for about half a second when I flip it on, the audio comes up VERY strong and loud. I figure that it's got to be something that someone will recognize immediately and something that I might never find  |
The sudden drop sounds like a "floating grid" condition on one of the audio stages, most likely the 1st audio stage. That's where the grid has no DC return path to ground, causing the tube to self-bias to near cutoff by space charge. Is the tube a 6Q7? If so, (with the set off) measure resistance from the grid cap connector to ground. On the highest R scale, if it reads infinity (open circuit), it would indicate a floating grid condition.
If you get some kind of resistance reading there, it would eliminate that possibility.