Teledyne MX300-I manual Watchdog, Error Codes

Service Manual MX300-I

Symptom	Why	What To Do
Cannot adjust	Critical settings require	A) If display is not flashing
calibration or alarm	two keys be pressed in	press lock key once to
settings	a specific order.	activate keys. Press desired
	LOCK/UNLOCK key is	function followed by the Up
		and Down key.
	active

Note: In the event that none of these procedures produce desired results, remove the batteries and return the unit to Teledyne for repair.

3.9 Watchdog

The MX300-I is equipped with a watchdog circuit that continuously monitors the electronics for proper operation. If the watchdog detects a failure, one of the following codes will appear on the LCD.

The error codes can appear on the LCD when batteries are first installed, during normal operation or if the unit is subjected to extreme shock. In some cases an additional digit is used in the error code to supply additional information. For example, the error code 6 and 7 are followed by another digit listed as (N) in Table 3.2. The error code 65 would indicate that a key is stuck and this key is the Silence key.

In addition to supplying visual error codes, the audio device will beep a number of times to indicate the general error in case the display is not functional.

NOTE: To reset the watchdog error code. Remove one battery for 5 seconds and replace. If the error persists contact your local representative or Teledyne for assistance.

Table 3-2 Error Codes

Error Code	Audio Beeps	Error
Indeterminate	2	The watchdog timer has timed out indicating a
		serious software error
30	3	Analog output is different from the expected value.
		May indicate a shorted or over-loaded analog
		output or a failure of the analog to digital converter
		or digital to analog converter circuit.

Teledyne Analytical Instruments 40