Teledyne GFC-7000T - Trace CO2 Analyzer - manual - Manual (Page 260)

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer
Teledyne Analytical Instruments 242
A voltmeter should be used to verify that the DC voltages are correct per the values in the table below,
and an oscilloscope, in AC mode, with band limiting turned on, can be used to evaluate if the supplies are
producing excessive noise (> 100 mV p-p).
Table 10-7: DC Power Supply Acceptable Levels
POWER
SUPPLY
ASSY
VOLTAG
E
CHECK RELAY BOARD TEST POINTS
MIN V MAX V FROM TEST POINT TO TEST POINT
NAME # NAME #
PS1 +5 Dgnd 1 +5 2 4.8 5.25
PS1 +15 Agnd 3 +15 4 13.5 16V
PS1 -15 Agnd 3 -15V 5 -14V -16V
PS1 Agnd Agnd 3 Dgnd 1 -0.05 0.05
PS1 Chassis Dgnd 1 Chassis N/A -0.05 0.05
PS2 +12
+12V Ret 6 +12V 7 11.75 12.5
PS2 Dgnd +12V Ret 6 Dgnd 1 -0.05 0.05
10.5.3. I
2
C Bus
Operation of the I
2
C bus can be verified by observing the behavior of D1 on the Relay PCA & D2 on the
Valve Driver PCA . Assuming that the DC power supplies are operating properly, the I
2
C bus is operating
properly if: D1 on the relay PCA and D2 of the Valve Driver PCA are flashing
There is a problem with the I 2 C bus if both D1 on the relay PCA and D2 of the Valve Driver PCA are
ON/OFF constantly (steady lit or steady off)
10.5.4. Touchscreen Interface
Verify the functioning of the touchscreen by observing the display when pressing a touchscreen control
button. Assuming that there are no wiring problems and that the DC power supplies are operating
properly, if pressing a control button on the display does not change the display, any of the following may
be the problem:
 The touchscreen controller may be malfunctioning.
 The internal USB bus may be malfunctioning.
You can verify this failure by logging on to the instrument using APICOM or a terminal program to any of
the communications ports. If the analyzer responds to remote commands and the display changes
accordingly, the touchscreen interface may be faulty.
10.5.5. LCD Display Module
Verify the functioning of the front panel display by observing it when power is applied to the instrument.
Assuming that there are no wiring problems and that the DC power supplies are operating properly, the
display screen should light and show the splash screen with logo and other indications of its state as the
CPU goes through its initialization process.