Teledyne 6400A - Sulfur dioxide analyzer - Manual (Page 149)

TAI Model 6400A SO
2
Analyzer Operator Manual, 02164, Rev. G
9-31
Like the display, the overall functioning of the CPU can be confirmed by a simple test.
1. Locate the CPU board on the mother board by referring to Figure 2-5.
2. Power the instrument on.
3. Locate the red LED at the top left edge of the board.
4. It should be flashing at a frequency of about once per second.
5. This flashing indicates the board is powered up and is executing instructions.
RS-232 diagnostic procedures are described in Section 9.3.2.2. It is possible for the UART driver
chip to malfunction in either or both of the input or output ports.