Power On Problems

Usually, when you turn on the LI-6400, there is about 5 or 6 second wait while the displays shows


Followed by sequence of messages until

Figure 20‑1. The version 6 startup screen. If it is not an XT, the middle line will be blank.

This is followed by the Welcome screen with a 5 second countdown (Figure 20‑2).

Figure 20‑2. The version 5 welcome screen.

This section describes some of the unusual things that might happen during the power up period.

Console Doesn’t Power On

If nothing happens when you power on:

  • Does the display flicker, or show any lines momentarily?
  • If no: It could be a totally dead battery, or blown battery fuse. Check the digital board fuse (Figure 19‑9). Make sure the fuse holder is making contact with both ends of the fuse. Sometimes, one end gets spread apart when a fuse is installed.
  • If yes: It could be a very discharged battery.
  • Try another one. If it’s not a battery or fuse, then it’s either a problem with the display, or a problem with the digital board. If you’ve had the display unplugged recently, make sure the display connector (Figure 19‑9) is plugged in correctly. If it is wrong, you may have already done some damage. Contact LI-COR for further assistance.

Screen Becomes Black

If the stored contrast file (/dev/.lcd) is missing, the display contrast may go full dark sometime during the INITIALIZING. sequence. After waiting about 10 seconds, press ctrl + shift + ↓ several times to adjust the contrast (this automatically regenerates the contrast file). It should work better on the next power on.

Powers off

If the instrument powers off right after you respond to

Is the Chamber/IRGA connected ?

  • Wrong power configuration?
  • You might be operating in following configuration: The LI-6020 charger connected to the console, and no battery (or a discharged one, or one with a blown fuse) connected to the console. This doesn’t work. See Powering the LI-6400.
    If you’ve got what appears to be a dead battery, see Figure 19‑9.
  • Cable or sensor head problem?
  • Try disconnecting all the cables from the console. There may be a problem in the IRGA or chamber that is pulling the voltage low enough to turn the console off. See if you can isolate it.

Welcome screen doesn’t appear

The /Sys/Autostart folder or its contents may have been tampered with (see The Autostart Folder on page 5-23 in the instruction manual). Try re-installing system software (Installing System Software).

Continually Blows a Fuse

The important questions here are 1) What fuse is blowing? 2) When does it happen? 3) Does it happen with the chamber/IRGA detached (but the cable attached)? 4) Does it happen with no cable attached?

Here are some hints:

  • Flow board fuse
  • Items in this circuit are the pump, chamber mixing fan (see The Mixing Fan), and 6400-02 or -02B LED light source (or LCF light source) fan, and the match valve. Try to isolate the problem. One of the steps might be to leave the chamber cable plugged into the console, but not into the sensor head, to determine if it is the cable itself that has a problem.
    Note also that when you power up normally, the match valve first tries to operate just before OPEN’s main screen appears. The pump and chamber fan stay off until the first time you enter New Measurements mode.
  • IRGA board fuse
  • Only the gas analyzers are on this circuit. If this fan is blown, you may not even know it, unless you notice the IRGAs have no dynamic response.
  • TEC fuses
  • Protects the circuit driving the thermoelectric coolers on the chamber.
  • Fan fuse
  • Protects against problems with the chamber mixing fan. If the fan is the culprit, however, it may be the flow board fuse that goes first.
  • Digital board fuse
  • If this is blown, you’ll have no display, and no keyboard control.