Gemmy Monster Head Repair

I'm not familiar with this prop, and this is too general of a question to answer -- but I'll see if I can help. Let's use a basic troubleshooting process: Start with the power supply (batteries or whatever powers the prop), check to see if you have power, check for opens or shorts in the circuit... then the next step is to check the connections to the various components, you may need to disassemble things to gain access. Take photos of your prop before and after removing things so you can put them back the way it was. Have a tray for small screws, I like ice cube trays for compartments. Make a circuit diagram on paper as you trace the circuits... Take time to methodically and go through and trace it one by one. Also post some pics of the prop or anything that looks questionable... Hope that helps