Troubleshooting and Service Teledyne API T803 CO2/O2 Analyzer Operation Manual
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remote commands and the display changes accordingly, the touchscreen interface
may be faulty.

11.6.5. LCD DISPLAY MODULE

Verify the functioning of the front panel display by observing it when power is
applied to the instrument. Assuming that there are no wiring problems and that
the DC power supplies are operating properly, the display screen should light and
show the splash screen with logo and other indications of its state as the CPU
goes through its initialization process.

11.6.6. RELAY BOARD

The relay board PCA (04135) can be most easily checked by observing the
condition of the its status LEDs on the relay board, as described in Section
12.6.3.1, and the associated output when toggled on and off through signal I/O
function in the diagnostic menu, See Section 11.1.3.
1. If the front panel display responds to key presses and D1 on the relay board
is NOT flashing then either the wiring between the Keyboard and the relay
board is bad, or the relay board is bad.
2. If D1 on the relay board is flashing and the status indicator for the output in
question (heater power etc.) toggles properly using the signal I/O function,
then the associated control device on the relay board is bad. (Several of the
control devices are in sockets and can be easily replaced).

11.6.7. SENSOR ASSEMBLY

Both the CO2 and O2 sensors have no user serviceable parts.

11.6.8. PRESSURE/FLOW SENSOR ASSEMBLY

The pressure/flow sensor PCA can be checked with a Voltmeter using the
following procedure which, assumes that the wiring is intact, and that the
motherboard and the power supplies are operating properly:
07276B DCN6418