Maybe the speaker failed or the headphone jack contacts are corroded.
Try plugging in head phones and see if they work. If they do it might
fix the speaker problem.

In fact the headphone jack of my Sony 2001 (about the same age) just
recently fell all apart. To use the radio without headphones you have to
solder together a couple of contacts inside.

If the headphone jack hasn't fallen apart, cleaning it is a good idea. Put
a drop of isopropyl alcohol or contact cleaner on a headphone plug, plug it
in and take it out several times.