Service Manual | MX300 | |
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3.9 Watchdog
The MX300 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 | |
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| serious software error | |
30 | 3 | Analog output is different from the expected value. | |
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| May indicate a shorted or | |
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| output or a failure of the analog to digital converter | |
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| or digital to analog converter circuit. | |
50 | 5 | The ADC circuit failed during POST. | |
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6 (5) | 6 | A stuck key has been detected. The second digit | |
| (There is no | example (5) on the display shows which key is stuck: | |
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| indication of | 0 | - Low Alarm |
| which key is | 1 | - Batt |
| stuck) | ||
| 2 | - Cal | |
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| 3 | - Up |
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| 4 | - Down |
Teledyne Analytical Instruments | 42 |