Teledyne 9110T Replacing the PMT, Hvps or TEC, Between measure and Auto Zero modes

Model 9110T NOx Analyzer Troubleshooting & Service

slowly. Wait 10 seconds between adjustments.

Note	During these adjustments, the NORM PMT value will fluctuate as the
	analyzer continues to switch between NO and NOx streams as well as
	between measure and Auto Zero modes.

13.Perform a span point calibration (see Section 9) to normalize the sensor response to its new PMT sensitivity.

14.Review the slope and offset values:

∙The slope values should be 1.000±0.300.

∙The offset values should be approximately 0.0 (-20 to +150 mV is allowed).

12.8.5.REPLACING THE PMT, HVPS OR TEC

The photo multiplier tube (PMT) should last for the lifetime of the analyzer, however, the high voltage power supply (HVPS) or the thermo-electric cooler (TEC) components may fail. Replacing any of these components requires opening the sensor module. This is a delicate assembly and it is recommend that you ensure the PMT, HVPS or TEC modules are, indeed, faulty before unnecessarily opening of the module.

CAUTION

QUALIFIED PERSONNEL

While the PMT or HVPS can be removed through the front panel without un- mounting the entire sensor module, we recommend turning off the instrument, opening its top cover and removing the entire assembly so that further repairs can be carried out at an anti-ESD workstation.

Follow the guidelines defined in Section14for preventing electrostatic damage to

electronic components.

1.Turn OFF the analyzer and disconnect the power cord.

2.Remove the cover.

3.Disconnect all pneumatic and electrical connections from the sensor assembly.

4.Remove the sensor assembly.

5.If the TEC is to be replaced, remove the reaction cell assembly at this point by unscrewing two holding screws.

∙This is necessary only if the repair being performed involves removing the PMT cold block.

Teledyne Analytical Instruments 312