Troubleshooting
Real Time Clock Problems
20-6
Using the LI-6400
20
Real Time Clock Problems
DoesnÕt Keep Time When Power Off
The first thing to check is the clockÕs battery (Figure 20-1). Measure its volt-
age relative to Test Point 10; it should be 2.7V or greater.
The battery (LI-COR part number 442-03791) is a ÒcoinÓ type, and is held in
place in a holder on the corner of the board. It is easily removed, but be sure
the instrument is powered off, lest you short the test points right in front of
the battery holder and blow a fuse.
If the batteryÕs life seemed unexpectedly short (it should be several years),
then the battery may draining because capacitor C3 is leaky. If C3 is leaky
enough, it can even prevent the clock from running while the instrument is
turned on (next section).
ÒClock StoppedÓ Message
OpenÕs main screen displays the time and date, which should update each sec-
ond. If the real time clock is not running, the message ÒClock StoppedÓ is dis-
played instead. If this happens, and the SET CLOCK program
(
on page 21-18) doesnÕt fix it, then you very likely have a
leaky capacitor C3. If you canÕt test or replace it, you might try cutting one
leg off to disable it. If C3 is the problem, disabling it will allow the clock to
run while the instrument is powered off, but youÕll have to set the time each
time you turn it off until C3 is replaced.
Clock battery
C3
TP10
Figure 20-1. Location of the clock battery, Test Point 10, and capacitor C3.
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...