Teledyne GFC-7001T - Trace CO Analyzer - Manual (Page 273)

Troubleshooting and ServiceTeledyne API – Model T300/T300M CO Analyzer
Teledyne Analytical Instruments 273
the associated output when toggled on and off through signal I/O function in the
diagnostic menu, see Section 12.1.3.
1. If the front panel display responds to button presses and D1 on the relay board is
NOT flashing then either the wiring between the touchscreen and the relay board is
bad, or the relay board is bad.
2. If D1 on the relay board is flashing and the status indicator for the output in question
(heater power, valve drive, etc.) toggles properly using the signal I/O function, then
the associated control device on the relay board is bad.
 Several of the control devices are in sockets and can be easily replaced.
 The table below lists the control device associated with a particular
function:
Table 12-8: Relay Board Control Devices
FUNCTION
CONTROL
DEVICE
IN SOCKET
Wheel Heater K1 Yes
Bench Heater K2 Yes
Spare AC Control K3 Yes
IZS Valves U4 Yes
IR Source Drive U5 No
The IR source drive output can be verified by measuring the voltage at J16 with the IR
source disconnected. It should be 11.5± 0.5 VDC.
12.5.7. SENSOR ASSEMBLY
12.5.7.1. SYNC/DEMODULATOR ASSEMBLY
To verify that the Sync/Demodulator Assembly is working, follow the procedure below:
1. Verify that D1 and D2 are flashing.
 If not, check the opto pickup assembly, Section 12.5.7.3 and the GFC Wheel
drive, Section 12.5.7.4.
 If the wheel drive and opto pickup are working properly then verify that
there is 2.4 ±0.1 VAC and 2.5 ±0.15 VDC between digital ground and TP 5
on the sync/demod board. If not then check the wiring between the
sync/demod and opto pickup assembly (see interconnect drawing, P/N
04216). If good then the sync/demod board is bad.
2. Verify that the IR source is operating, Section 12.5.7.5.
3. With the analyzer connected to zero air, measure between TP11 (measure) and
analog ground, and TP12 (reference) and analog ground.
 If they are similar to values recorded on the factory data sheet then there is
likely a problem with the wiring or the A/D converter.
 If they are not then either the sync demodulator board or the IR-
photodetector are bad. See Section 12.4.1.4 for problems with the IR-
photodetector TEC drive.