Troubleshooting

In this section, we describe how to identify some potential problems. If you can't find a solution here, contact your local distributor or LI-COR technical support for more help.

Instrument will not power on

Power supply adequate? The power supply should source at least 1.2 amps at 12 VDC (minimum of 14 watts during warmup).

Blown fuse? The instrument can be powered from the power jack or pins one and two on the terminal strip. Each connection has its own fuse.

  • If you are unable to power on the instrument using the jack, but can power it on using the terminal strip, you probably have a blown power jack fuse.
  • If the opposite is true, you probably have a blown terminal strip fuse.
  • If you can't power it using either connection, you may have blown both fuses.

Check the resistance across the fuse contacts using an ohm meter. A reading of 0 means that the fuse is good; a reading of 1 indicates that the fuse is blown.

See Replacing a fuse for complete instructions.

Unable to span or zero the instrument

Dirt in the optics? If the optical cell becomes contaminated, the instrument will drift in either the zero or span.

See Cleaning the optical bench for complete instructions.

Instrument reports -50 ppm CO2 or measurements jump around

If the instrument measures -50 ppm or the measurements are going between negative and positive values, or just simply not making any sense, the optical source may have failed or be in the midst of failure. Contact technical support for additional troubleshooting help.