12-02-2009, 08:37 AM
Hi
Good news indeed! Congratulations on getting your 42-380 up and running!
Are you saying that a preset AM station drifts when you use one of the preset buttons, or do they cut in and out?
If they are drifting, replace capacitors (5) and (9), 370 pF each, with new mica capacitors - do not use ceramics in this application unless they have an NP0 rating. Here, it is much better to spend the extra $ and get quality mica caps as replacements to prevent station drift. Most ceramics will drift as the radio warms up; you don't want that to happen. The originals are mica but are of open construction, coated only in wax, and are almost always bad by now. New dipped mica caps and NP0 ceramic caps will not allow the preset stations to drift.
If your preset stations are cutting out, the pushbutton mechanism is still dirty. These can be sometimes very difficult to get clean and to get working properly. I repaired one once, where the pushbuttons refused to work properly no matter how much I cleaned them, Replacement of the entire pushbutton assembly (no easy task!) was the only cure. Fortunately, the parts set used as a donor had a good pushbutton assembly...
Good news indeed! Congratulations on getting your 42-380 up and running!
Are you saying that a preset AM station drifts when you use one of the preset buttons, or do they cut in and out?
If they are drifting, replace capacitors (5) and (9), 370 pF each, with new mica capacitors - do not use ceramics in this application unless they have an NP0 rating. Here, it is much better to spend the extra $ and get quality mica caps as replacements to prevent station drift. Most ceramics will drift as the radio warms up; you don't want that to happen. The originals are mica but are of open construction, coated only in wax, and are almost always bad by now. New dipped mica caps and NP0 ceramic caps will not allow the preset stations to drift.
If your preset stations are cutting out, the pushbutton mechanism is still dirty. These can be sometimes very difficult to get clean and to get working properly. I repaired one once, where the pushbuttons refused to work properly no matter how much I cleaned them, Replacement of the entire pushbutton assembly (no easy task!) was the only cure. Fortunately, the parts set used as a donor had a good pushbutton assembly...
--
Ron Ramirez
Ferdinand IN
