Teledyne 300M - Manual (Page 97)

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A
10.2.2 Checking the CPU and Display
When the analyzer is turned on, the front panel display should energize and the green "Sample"
LED should light. If proper DC power is present (see Section 10.2.1), the absence of these
actions will usually indicate either a CPU or Display failure. To determine which module is
defective, perform the following procedure:
1. Turn off power.
2. Remove the ribbon cable from the CPU board to the Display.
3. Turn Power on.
4. A cursor character should appear in the upper left corner of the display. If it does not, the
display is defective and should be replaced. If the cursor does appear, it is probable that the
CPU is faulty.
10.2.3 Checking the Keyboard
During normal analyzer operation, depressing the right most key of the keyboard should cause a
change of display modes. If it does not, check:
1. Cable connections
2. CPU and Display operation (see Section 10.2.2)
If these checks are satisfactory, it is probable that the keyboard is defective and should be
replaced.
10.3 Troubleshooting Using Warning Messages
The most common and/or serious instrument failures will result in a warning message (or
messages) being displayed on the front panel. Table 10-1 lists the warning messages which the
analyzer may display, along with their meaning and the recommended corrective action. It
should be noted that if multiple (more than 2 or 3) warning messages occur at the same time, it is
often an indication that some fundamental analyzer sub-system (power supply, V/F board, CPU)
has failed rather than an indication of the multiple failures referenced by the warnings. In this
situation, it is recommended that proper operation of power supplies (see Section 10.6.4) and the
V/F Board (see Section 10.6.3) be confirmed before addressing the specific warning messages.
10-3