The SW band also works great until I tune to stations at greater than about 12MHz. As I enter this range, a static oscilation (kind of a squeal) occurs. Sometimes when I turn off the set and turn it back on the oscillation goes away. The oscillations are more pronounced when the volume control is up high. Some stations in this frequency range do come in but they are a bit distorted and somewhat overcome by the squeal... I've recapped many (not all) of the capacitors..The set had an open secondary on the SW RF antenna coil which I rewound (3 turn secondary). Once rewound the lower frequencies came in great. Anyone have an idea on where to go from here?
Are bypass caps connected to the same points as the originals? Higher frequencies are more critical. You might try bypassing caps already in the circuit.
Could there be a microphonic tube?
Try grounding the 6A8 top cap, 6K7 top cap, see if this stops oscillation.
Norm
:I have a 3 band Crosley model 716. The am band works great (except for some static on the lower frequencies which goes away when a strong station is tuned in). The am band is free of any oscillations or squeals.
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:The SW band also works great until I tune to stations at greater than about 12MHz. As I enter this range, a static oscilation (kind of a squeal) occurs. Sometimes when I turn off the set and turn it back on the oscillation goes away. The oscillations are more pronounced when the volume control is up high. Some stations in this frequency range do come in but they are a bit distorted and somewhat overcome by the squeal... I've recapped many (not all) of the capacitors..The set had an open secondary on the SW RF antenna coil which I rewound (3 turn secondary). Once rewound the lower frequencies came in great. Anyone have an idea on where to go from here?