User's Manual

General Troubleshooting & Repair of the M400E Analyzer M400E Ozone Analyzer Operator’s Manual
13.3. USING THE INTERNAL ELECTRONIC STATUS LEDS
Several LEDs are located inside the instrument to assist in determining if the analyzers CPU, I
2
C bus and Relay
PCA are functioning properly.
13.3.1. 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 DS5 is flashing nor have any characters 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 13-2: CPU Status Indicator
13.3.2. RELAY PCA STATUS LED S
There are sixteen LEDs located on the Relay PCA. Some are not used on this model.
13.3.2.1. I
2
C Bus Watchdog Status LEDs
The most important is D1 (see, which indicates the health of the I
2
C bus.
Table 13-4: Relay PCA Watchdog LED Failure Indications
LED Function Fault Status Indicated Failure(s)
D1
(Red)
I
2
C bus Health
(Watchdog Circuit)
Continuously ON
or
Continuously OFF
Failed/Halted CPU
Faulty Motherboard, Keyboard or Relay PCA
Faulty Connectors/Wiring between Motherboard,
Keyboard or Relay PCA
Failed/Faulty +5 VDC Power Supply (PS1)
If D1 is blinking, then the other LEDs can be used in conjunction with
DIAG Menu Signal I/O to identify hardware
failures of the relays and switches on the Relay.
240 04315 Rev. C1