Does the radio have a shortwave band? If not may have shortwave stations in your area which bleed over into the boradcast band?
Slightly moving IF adjustments won't cause this problem.
:Hi. Have a strange question. Started working on a Traveler AM record player i got from an auction for a couple bucks. It had an output tube open, pilot light, and one resistor. Replaced the 50L6 the pilot light, and the resistor with exactly the same resistance and wattage. Brought it up to full power, got some noise and put it aside for lunch. Came back and started tuning in the trimmers. Lined the radio up exactly as the schematics said, and stations came in loud and clear. Problem was the stations were shortwave!!! Only moved the I.F. about a 32nd of an inch. moved it back where it was to start and same thing only with fainter output. Looked the wiring over 2 times against the schematic and nothing has been monkeyed with. Anybody got any ideas what is up? I'm stumped. Thanks for your inputs and "keep 'em glowing".