I've gotten around to cleaning and checking the speedometer. It seems to work correctly - I connected a drill to the cable and it registered up to 20 mph. I checked the bulbs and the red light and the instrument lights work, but the neutral light is burnt out. I'd like to clean the glass, but don't know how to get the unit apart. I used a battery charger to test the bulbs. How do I disassemble the cluster? I removed the three small Philips screws, but it didn't see to fee anything.