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General Troubleshooting & Repair of the M400E Analyzer M400E Ozone Analyzer Operator’s Manual
13.7.7.4. Control Inputs
The control input bits can be tested by applying a trigger voltage to an input and watching changes in the status
of the associated function under the SIGNAL I/O submenu:
EXAMPLE: to test the “
A” control input:
1. Under the
DIAG SIGNAL I/O menu (See Section13.1.3), scroll through the inputs and outputs until
you get to the output named
EXT_ZERO_CAL.
2. Connect a jumper from the
“+” pin on the appropriate connector to the “U” on the same connector.
3. Connect a second jumper from the “” pin on the connector to the “
A” pin.
4. The status of
EXT_ZERO_CAL should change to read “ON”.
Table 13-11: M400E Control Input Pin Assignments and Corresponding Signal I/O Functions
INPUT CORRESPONDING I/O SIGNAL
A EXT_ZERO_CAL
B EXT_LOW_SPAN_CAL
1
C EXT_SPAN_CAL
D, E& F NOT USED
1
Only operates if either Z/S or IZS option is installed
13.7.8. CPU
There are two major types of failures associated with the CPU board: complete failure and a failure associated
with the Disk-On Chip on the CPU board. If either of these failures occur, contact the factory.
For complete failures, assuming that the power supplies are operating properly and the wiring is intact,
the CPU is bad if on powering the instrument:
The vacuum fluorescent display shows a dash in the upper left hand corner.
The CPU Status LED, DS5, is not flashing (See Section 13.3.1).
There is no activity from the primary RS-232 port on the rear panel even if “? <ret>” is pressed.
In some rare circumstances this failure may be caused by a bad IC on the motherboard, specifically U57
the large, 44 pin device on the lower right hand side of the board. If this is true, removing U57 from its
socket will allow the instrument to startup but the measurements will be incorrect.
If the analyzer stops part way through initialization (there are words on the vacuum fluorescent display)
then it is likely that the DOC has been corrupted.
252 04315 Rev. C1