Teledyne GFC-7000E - Trace CO2 Analyzer - Manual (Page 194)

Model GFC7000E Instruction Manual TROUBLESHOOTING & REPAIR PROCEDURES
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11. TROUBLESHOOTING & REPAIR PROCEDURES
This section contains a variety of methods for identifying the source of performance problems with
the analyzer. Also included in this section are procedures that are used in repairing the
instrument.
CAUTION
The operations outlined in this chapter are to be performed by qualified
maintenance personnel only.
CAUTION
Risk of electrical shock. Disconnect power before performing the
following operations.
11.1. General Troubleshooting Hints
The analyzer has been designed so that problems can be rapidly detected, evaluated and
repaired. During operation, the analyzer continuously performs self-check diagnostics and
provides the ability to monitor the key operating parameters of the instrument without disturbing
monitoring operations.
A systematic approach to troubleshooting will generally consist of the following four steps:
1. Note any WARNING MESSAGES and take corrective action as required.
2. Examine the values of all TEST functions and compare to factory values. Note any major
deviations from the factory values and take correction action as required.
3. Use the internal electronic status LED’s to determine whether the CPU and I 2 C buses are
running, and if the sync/demodulator and relay board are operating properly. Verify that the
DC power supplies are operating properly by checking the voltage test points on the relay
board. Please note that the analyzer’s DC power wiring is color-coded and these colors match
the color of the corresponding test points on the relay board.
4. SUSPECT A LEAK FIRST! Data from Teledyne Instruments’ service department indicates
that 50% of all problems are eventually traced to leaks in the pneumatic connections and gas
lines of the analyzer itself, the source of zero air, span gases or sample gas delivery system.
Check for gas flow problems such as clogged or blocked internal/external gas lines, damaged
seals, punctured gas lines, a damaged pump diaphragm, etc.
5. Follow the procedures defined in Section 11.4 for confirming that the analyzer’s basic
components are working (power supplies, CPU, relay board, sync/demod board, keypad, GFC
wheel motor, etc.). See Figure 3-11 for general layout of components and sub-assemblies in
the analyzer. See the wiring Interconnect Drawing and Interconnect List, documents 04216
and 04217.