Symptom - Plasma Won't Light; Symptom - No Signal; Symptom - Low Signal - ABB PGC5000 Service Instruction

To determine the source of the problem:
1. Identify whether the problem is with the chromatographic oven or the detector. In general, if
the problem is with component retention times and not component sensitivity, the problem is in
the chromatographic oven and not the detector.
Ask: "What was the last thing done to the system?" Most problems are associated with the
latest change made to the system, so this is the best place to begin look for the problem.
If the considerations above identify the detector as the primary cause of the malfunction, use the
following sections to help identify and correct the problem.
3.1 Symptom – Plasma won't light
Possible Cause
No power
Air in plasma
Back pressure too high
Wrong plasma gas
Defective electronics
3.2 Symptom – No signal
Possible Cause
No Power
Air in plasma
Signal cable problem
Wrong bias voltage
3.3 Symptom – Low signal
Possible Cause
Leakage in the
chromatographic system
Wrong reaction gas
Plugged exhaust tube
1 0 | DB DI D | 8 92 J0 09 MN A E
Action(s)
If the fuse is intact, contact customer support for further assistance.
The presence of too much air in the plasma will often cause the
plasma not to light.
Purge the system with reaction gas for at least 15 minutes.
If the plasma still will not light, check for air leaks in all of the fittings.
If there is too high of a restriction in the exhaust line, the detector
plasma will not light.
Replace the exhaust/signal tube with a new one and see if the plasma
will light.
Verify that the reaction gas is either helium or argon. Replace if
necessary.
See sections 3.2 and 3.3.
Action(s)
If the fuse is intact, contact customer support for further assistance.
Observe the plasma tube in a dark environment. There should be a
pink or almost white glow in the plasma tube. If the tube is blue and
the signal is low, there is nitrogen in the plasma.
Verify that the correct reaction gas (helium or argon) is being used.
Turn off the power to the plasma and check the gas supply, check for
leaks, and verify the proper flow rate.
Verify that the collector shield BNC fitting contacts the exhaust tube.
To do this, remove the BNC cable from the collector shield. Verify
contact between the center pin of the BNC and the exhaust tube using
a VOM or continuity tester. Re-connect the BNC cable to the collector
shield. Verify the cable is connected to the collector shield and the
electrometer board.
Using a VOM meter, verify the voltage between the Bias test point and
chassis ground on the Power Supply Board. The voltage should be +10
volts DC.
Action(s)
Verify retention times for the analytes of interest.
If OK, check for leakage on all the fittings on the detector end of the
system.
If retention times have shifted, check for leaks on the sample
introduction side of the system.
Using nitrogen as a reaction gas will result in a low signal. Verify that
the proper reaction gas is being used. Replace if necessary.
Unique problem that will manifest itself with a lower signal and slower
retention times.
Visually inspect the exhaust tube to identify if any materials have
plugged the tube. If plugged, insert a cleaning wire into the exhaust
tube to remove the blockage.
If these actions do not correct the problem, replace the exhaust tube.