### MP-021 Atlas Y2 counter fault

The amp/check/divide board detected a Y2-axis counter fault. Possible causes are:

1. The laser beam is blocked.

2. The laser beam is not properly aligned in the interferometer.

3. There is too much DC offset in the OPD Lissajous.

4. There is not sufficient amplitude in the OPD Lissajous.

5. The axis is moving too fast (over 25 in/sec. for laser machines).

What you should do

1. To clear the error, click Clear error in the XYZ Display window. To clear it using an RCU-II, press and hold down the Servo Power Off button and then press the Joy button twice.

2. If the error reoccurs, call your Giddings & Lewis service representative.