Troubleshooting & Repair Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 276

13.1.4.3. Relay Board Status LED’s

There are eight LED’s located on the Relay Board. The most important of which is D1, which indicates the
health of the I2C bus. If D1 is blinking the other faults following LED’s can be used in conjunction with DIAG
menu signal I/O to identify hardware failures of the relays and switches on the relay (see Section 13.1.3 and
Appendix D).
Table 13-4: I2C Status LED Failure Indications
LED FUNCTION FAULT STATUS INDICATED FAILURE(S)
D1
(Red)
I2C bus Health
(Watch Dog
Circuit)
Continuously ON
or
Continuously OFF
Failed/Halted CPU
Faulty Motherboard, Keyboard or Relay Board
Faulty Connectors/Wiring between Motherboard,
Keyboard or Relay Board
Failed/Faulty +5 VDC Power Supply (PS1)

STATUS LED’s DC VOLTAGE TEST

POINTS

RELAY PCA PN 04135
Figure 13-5: Relay Board Status LEDs