1. The main light path of the instrument is not bright. The main reasons are:
(1) The instrument power supply has no voltage output;
(2) the transformer fuse is blown;
(3) The light source bulb or reading microscope bulb of the light path system is damaged;
(4) The wire between the instrument base and the transformer is not connected properly.

2. The digital display box does not display, mainly because:
(1) The instrument base and digital display box cables are not connected properly;
(2) The back panel switch of the digital display box is not turned on;
(3) The power cord of the digital display box is not plugged in properly;
(4) The X and Y coordinate signal cables between the grating sensor and the digital display box on the instrument base are not connected properly;
(5) The digital display box circuit is short-circuited, broken or damaged.

3. The digital display box displays messy strokes or unstable display of the last position. The main reasons are:
(1) the microcomputer did not complete the automatic power-on and did not enter the normal program;
(2) The segment or bit scanning fails, and the segment or bit driving tube needs to be replaced;
(3) There is a seismic source near the instrument;

4. The digital display box suddenly alarms or misses counting. The main reasons are:
(1) The workbench moves too fast;
(2) The signal cable is not in good contact;
(3) The boot time is too long;
(4) The grating sensor signal is too small due to the change of the gap between the main grating and the auxiliary grating. Check the cable connection first, and then press the corresponding alarm coordinate reset key. If the alarm is released, it means that the workbench moves too fast. If it cannot be released, it is necessary to adjust the grating signal and check it with an oscilloscope. The waveforms of the two grating signals should be sine waves, with peak-to-peak values greater than 2V and equal, with a phase difference of 90 degrees and a circle on the oscilloscope.

5. The value of digital display box is out of tolerance. The main reasons are:
When the grating ruler is installed, it is not parallel to the guide rail of the workbench. The grating ruler should be adjusted to be parallel to the guide rail in the X and Y directions respectively, and the error should not be greater than 10μm m..

6. Press the keyboard without response, the main reasons are: