Common causes:

• Power not on
• Laser or laser power supply failure
• Stuck moving mirror bearing
• Broken scanning mirror
• Failed electronics

Suggestions:

Turn power on.

Look for red laser beam in interferometer area. If not present, replace laser and/or laser power supply. See disclaimer for safety warning. Be sure to disconnect spectrometer power before replacing components.

Without touching optical components, manually move moving mirror assembly. If it is hard to move or has a sticky spot, try to clear by moving back and forth. If this is unsuccessful, bearing replacement may be necessary.

Inspect interferometer area. If moving mirror is broken it will need to be replaced.

Check electronics. Are power supplies at proper voltages. Is main CPU running?