1. Unbalanced hairspring
Unbalanced balance spring is a common failure of pressure gauges. The main reason is excessive pressure during use and man-made damage during disassembly of the movement. The turbulence of the balance spring will cause a greater zero error; the pointer jumps, which will increase accidental errors; the friction of the connecting rod transmission device will increase, which will increase the error of the instrument. The most effective method for hairspring disease is to replace the hairspring of the same specification. Without spare parts, messy hairsprings can be sorted and reused.
2. Wear of transmission mechanism
The transmission mechanism is usually called a movement. The sector gear of the movement, the tooth meshing surface of the central gear and the matching shaft hole have been partially worn out, which will cause the instrument to jam or indicate a larger error. When the pressure gauge measures a basically constant but unstable pressure for a long time, the fault is prone to long-term wear. It can be repaired by replacing it with a movement of the same specification.
3. The pointer will not return to zero
The reason why the pointer does not return to zero is that the pointer rubs on the dial surface or watch glass. You can bend the pointer tip slightly to eliminate friction; if the balance spring is too loose, you can adjust the tension of the balance spring. The "residual deformation" of the spring tube is an irreparable fault. For watches with a normal transmission mechanism and hairspring, most watches can usually reset their hands to zero after adjustment.