Teledyne 9110T instruction manual Using the Internal Electronic Status Leds, CPU Status Indicator

Model 9110T NOx Analyzer Troubleshooting & Service

12.3. USING THE INTERNAL ELECTRONIC STATUS LEDS

Several LEDs are located inside the instrument to assist in determining if the analyzer’s CPU, I2C bus and Relay PCA are functioning properly.

12.3.1. 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 TAI's Customer Service Department (see Section 12.10) 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.

Motherboard

CPU Status LED

Figure 12-2: CPU Status Indicator

12.3.2. RELAY PCA STATUS LEDS

There are sixteen LEDs located on the Relay PCA. Some are not used on this model.

12.3.2.1. I2C Bus Watchdog Status LEDs

The most important is D1, which indicates the health of the I2C bus.

Table 12-4: Relay PCA Watchdog LED Failure Indications

LED	Function	Fault Status	Indicated Failure(s)
			Failed/Halted CPU
D1	I2C bus Health	Continuously ON	Faulty Motherboard, Touchscreen or Relay PCA
(Red)	(Watchdog Circuit)	or	Faulty Connectors/Wiring between Motherboard,
		Continuously OFF	Touchscreen 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 PCA.

Teledyne Analytical Instruments 270