It may be possible to repair a broken Gendex 770 tube head, depending on the extent of the damage. However, repairing dental equipment can be complex and should only be done by a qualified and experienced technician.
If you attempt to repair the tube head yourself, you may risk causing further damage to the equipment or injuring yourself. Additionally, attempting to repair the tube head yourself may void any warranties or support agreements you have with the manufacturer or distributor.
It's best to contact the manufacturer or an authorized repair center to get a professional evaluation of the damage and an estimate for repair. They can assess the damage and determine if it is possible to repair the tube head, and provide you with a cost estimate for the repair.
If the cost of the repair is too high or if the tube head is too damaged to be repaired, you may need to consider purchasing a replacement tube head.