Crystal electric roller shutter motor will not start:
1. Short circuit in the wire.
2. Faulty running capacitor.
3. Damaged bridge rectifier or electromagnetic coil, or stuck brake.
4. Limit switch normally-closed contact open.
5. Relay coil oxidized or already damaged, or contaminated.
6. Overheat protection failed.
7. Brake stuck.
8. Ran too long, thermal protection tripped.
Crystal electric roller shutter brake slip causes:
1. Brake pad soaked with oil.
2. Spring compression reduced.
3. Electromagnetic unit may be fitted wrong.
Crystal electric roller shutter manual chain will not pull:
1. Ring chain jammed in the cross slot.
2. Electromagnetic fasteners loose.
Crystal electric roller shutter gravity-drop failure causes:
1. Manual pull rod bent.
2. Too much gap between manual pull rod and washer.
3. Gearbox motor lube lost effect.
Crystal electric roller shutter loud noise causes:
1. Shutter motor rail resistance too high.
2. Mounting plate fasteners loose.
3. Chain or sprocket worn too much from long use.