Teledyne 9110EH - Nitrogen Oxides Analyzer - Manual (Page 228)

Troubleshooting & Repair Model 9110EH Instruction Manual
• Connect a second jumper from the ‘-‘ pin on the STATUS connector to the A pin on
the CONTROL IN connector. The instrument should switch from SAMPLE mode to
ZERO CAL R mode.
• Connect a second jumper from the ‘-‘ pin on the STATUS connector to the B pin on
the CONTROL IN connector. The instrument should switch from SAMPLE mode to
SPAN CAL R mode.
In each case, the M9110EH should return to SAMPLE mode when the jumper is removed.
11.5.10. CPU
There are two major types of CPU board failures, a complete failure and a failure associated
with the Disk-On-Chip (DOC). 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 faulty if on power-on:
• The vacuum fluorescence display does not show a dash in the upper left hand corner
• There is no activity from the primary RS-232 port (COM1) on the rear panel even if
“? ” 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 start up but the measure-
ments will be incorrect.
• If the analyzer stops during initialization (the vacuum fluorescence display shows
some text), it is likely that the DOC, the firmware or the configuration and data files
have been corrupted or that the wrong firmware was uploaded or does not have the
correct filename.
11.5.11. RS-232 Communication
11.5.11.1. General RS-232 Troubleshooting
TAI analyzers use the RS-232 protocol as the standard, serial communications protocol.
RS-232 is a versatile standard, which has been used for many years but, at times, is
difficult to configure. TAI conforms to the standard pin assignments in the implementation
of RS-232. Problems with RS-232 connections usually center around 4 general areas:
• Incorrect cabling and connectors. This is the most common problem. See Table 0-16
for connector and pin-out information and Section 6.9.3 for cable connections.
• The communications (baud) rate and protocol parameters are incorrectly configured.
See Section 6.9.7 on how to set the baud rate.
• The COM port communications mode is set incorrectly (Section 6.9.6).
• If a modem is used, additional configuration and wiring rules must be observed. See
Section 6.11.3.
• Incorrect setting of the DTE - DCE switch. Typically, the red LED is on as soon as
you power up the analyzer. If not, contact the factory, as this indicates a problem
with the motherboard. As the analyzer is connected to the computer with a cable,
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