Try giving it a good cleaning. For starters, use a Q-Tip and some isopropyl alcohol (90+ percent pure) to wipe off the head, in up/down direction. You can’t really see whether the head is clean or dirty so keep scrubbing for a while. Also put the recorder in service mode and play a DCC tape; preferably a prerecorded one with a brown pressure pad. Check how many tracks are showing “00”. If they all show FF, there’s a chance that the head is defective but if you’re getting analog sound, there’s a chance it could be salvageable. Clean those capstans too.
Also check the pinch rollers; those are often an issue on 3rd gen recorders. DCC is very sensitive to speed variations such as the ones caused by worn out pinch rollers. They can be easily replaced and aren’t very expensive.