Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 257)

Troubleshooting & Repair Model 9110TH NOx Analyzer
Teledyne Analytical Instruments 237
7.5.10.4. Control Inputs
The control input bits can be tested by the following procedure:
 Connect a jumper from the +5 V pin on the STATUS connector to the +5 V
on the CONTROL IN connector.
 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 9110TH/M should return to SAMPLE mode when the jumper is
removed.
7.5.11. CPU
There are two major types of CPU board failures, a complete failure and a failure
associated with the Disk-On-Module (DOM). 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:
 There is no activity from the primary RS-232 port (labeled RS232) on the
rear panel even if “? <RETURN>” 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 measurements will be incorrect.