06-07-2010, 12:09 AM
Last week I finished work on a 41-81 portable. I think I may have a problem with the AVC, unless maybe it just isn't supposed to work too well on this simple radio. Far away stations come in quite weakly, though I can listen to them easily by turning up the volume. Strong, nearby stations are so strong that I can hear them easily even with the volume all the way down.
I replaced all of the tubular caps, and I'm sure I replaced the resistors in the AVC circuit (a 4.7 meg and a 10 meg.) There is a 250 mmf mica in the AVC that I did not replace. I think this one bypasses what's left of the RF to ground after the detector diode and before both the volume control and the AVC.
Before I tear into it again, does it seem to anyone that the 250 mmf mica is suspect? Or should I just not expect too much from this simple, 4 tube radio? I have other old portables that don't have great AVC either, but on a modern Walkman-type, the distant and strong stations come in at about the same volume. The noise level is higher on the more distant station, as one would expect.
Any other suggestions? I can't find any other components in the AVC that I did not replace, unless it is the IF transformers.
I replaced all of the tubular caps, and I'm sure I replaced the resistors in the AVC circuit (a 4.7 meg and a 10 meg.) There is a 250 mmf mica in the AVC that I did not replace. I think this one bypasses what's left of the RF to ground after the detector diode and before both the volume control and the AVC.
Before I tear into it again, does it seem to anyone that the 250 mmf mica is suspect? Or should I just not expect too much from this simple, 4 tube radio? I have other old portables that don't have great AVC either, but on a modern Walkman-type, the distant and strong stations come in at about the same volume. The noise level is higher on the more distant station, as one would expect.
Any other suggestions? I can't find any other components in the AVC that I did not replace, unless it is the IF transformers.
John Honeycutt