I might add here that many receivers 1/8 inch and 1/4 inch headphone connectors can and usually eventually do get oxidized contacts, where you usually can not reach them to clean. polish and lightly lube them.

One "tool" we use is to lightly saturate a "Q Tip" like cotton applicator, with quality tuner cleaner/lube, where MOST but not ALL of the cotton at the tip is smashed to make tinier, or removed to leave a small amount cotton on these.

Making sure that the cotton comes back to you, you might CAREFULLY insert into the headphone jack and rotate a few times, circulating back and forth as well.

That will in many instances, clean-and-lube enough of the contacts that likely caused your initial problems.

Again, making sure no cotton is left inside the connector, you might have to repeat the above two or so times to really clean what can be.

You can also do the above after removing the chassis totally, thus exposing the connector more fully, possibly gaining you better access to perform the above.

As a final note, we have done the above for a great many years on receivers of all ages, many Sat 800's, Tecsun PL's, vintage Grundigs, and others.

Headphone jacks/plugs are a constant, somewhat chronic source of exciting problems, especially as they or the headphones being plugged in age and/or oxidation and dirty contacts set in.

Joe