DCC 951 Testing the head in situ

Hi, Having changed the pinch rollers belts and gear wheel on my 951 I’m still having issues with it in that it still wont record. Is there a way to test the head in situ to prove the head and recording electronics are working as they should? If I can establish the electronics are ok, I can then look at the mechanical side again. I’m determined to get one of these fully operational!