Teledyne 200E, Instruction Manual, Page: 232 / 302

Model 200E Instruction Manual Troubleshooting & Repair
ambient (room) temperature because of the internal heating zones from the NO
2
converter,
reaction cell and other devices.
• To check the box temperature functionality, we recommend to check the
BOX_TEMP signal voltage using the SIGNAL I/O function under the DIAG Menu
(Section 11.1.3). At about 30° C, the signal should be around 1500 mV.
• We recommend to use a certified or calibrated external thermometer / temperature
sensor to verify the accuracy of the box temperature by placing it inside the chassis,
next to the thermistor labeled
XT1 (above connector J108) on the motherboard.
11.5.20. PMT Temperature
PMT temperature should be low and constant. It is more important that this temperature is
maintained constant than it is to maintain it low. The PMT cooler uses a Peltier, thermo-
electric cooler element supplied with 12 V DC power from the switching power supply PS2.
The temperature is controlled by a proportional temperature controller located on the
preamplifier board. Voltages applied to the cooler element vary from 0.1 to 12 VDC. The
temperature set point (hard-wired into the preamplifier board) will vary by ±1
° C due to
component tolerances. The actual temperature will be maintained to within 0.1° C around
that set point. On power-up of the analyzer, the front panel enables the user to watch that
temperature drop from about ambient temperature down to its set point of 6-8° C. If the
temperature fails to adjust after 30 minutes, there is a problem in the cooler circuit. If the
control circuit on the preamplifier board is faulty, a temperature of –1° C
is reported.
11.6. Repair Procedures
This section contains some procedures that may need to be performed when a major
component of the analyzer requires repair or replacement. Note that maintenance
procedures (e.g., replacement of regularly changed expendables) are discussed in
Chapter 9 (Maintenance) are not listed here. Also note that Teledyne-API customer service
may have a more detailed service note for some of the below procedures. Contact customer
service.
11.6.1. Disk-on-Chip Replacement
Replacing the Disk-on-Chip (DOC) will cause all of the instrument configuration parameters
to be lost unless the replacement chip carries the exact same firmware version. iDAS data
will always be lost and, if possible, should be downloaded prior to changing the DOC. If the
analyzer is equipped with at least one EEPROM flash chip (standard configuration), the
configuration settings are stored on the EEPROM. It is recommended to document all
analyzer parameters that may have been changed, such as calibration, range, auto-cal,
analog output, serial port and other settings before replacing the CPU chip. Refer to Figure
10-12 for locating the DOC and other CPU components.
• Ground yourself to prevent electrostatic damage to electronic components.
• Turn off power to the instrument, fold down the rear panel by loosening the
mounting screws. You may have to lift up the analyzer cover to prevent some
connectors on the CPU board to brush against the cover.
• When looking at the electronic circuits from the back of the analyzer, locate the
Disk-on-Chip on the CPU board. The chip should carry a label with analyzer model
number (M200E), firmware revision (example: M200E_C7.EXE), date and initials of
044100102 Rev A 217