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Model 300E Carbon Monoxide Analyzer
Instruction Manual
TROUBLESHOOTING & REPAIR PROCEDURES
P/N 04288 REV: A
195
11.1.4.
Internal Electronic Status LED’s
Several LED’s are located inside the instrument to assist in determining if the
analyzers CPU, I
2
C bus and Relay Board, GFC wheel and the Sync/Demodulator
Board are functioning properly.
11.1.4.1. CPU Status Indicator
DS5, a red LED, that is located on upper portion of the motherboard, just to the
right of the CPU board, flashes when the CPU is running the main program loop.
After power-up, approximately 30 – 60 seconds, DS5 should flash on and off. If
characters are written to the front panel display but DS5 does not flash then the
program files have become corrupted, contact customer service because it may be
possible to recover operation of the analyzer. If after 30 – 60 seconds neither the
DS5 is flashing and no characters have been written to the front panel display then
the CPU is bad and must be replaced.
Mother Board
P/N 04069
CPU Status LED
Figure 11-3: CPU Status Indicator