Instrument Maintenance T400 Ozone Analyzer Operator’s Manual
238
Figure 11-3: Optical Bench – Lamp Adjustment/ Installation
11.3.7.3. UV Lamp Replacement
This procedure details the steps for replacement of the UV source lamp in the optical
bench assembly. This procedure should be done whenever the lamp can no longer be
adjusted as described in Section 11.3.7.2.
CAUTION – UV Radiation Risk
Power down the instrument before proceeding with UV lamp replacement.
1. Turn the analyzer off.
2. Remove the cover from the analyzer.
3. Locate the Optical Bench Assembly (see Figure 3-5).
4.
Locate the UV lamp at the front of the optical be
nch assembly (see Figure 13-17)
5.
Unpl
ug the lamp cable from the power supply connector on the side of the optical
bench.
6. Slightly loosen (do not remove) the UV lamp setscrew and pull the lamp from its
housing.
7. Install a new lamp in the housing, pushing it all the way in.
Leave the UV lamp setscrew loose for now.
8. Turn the analyzer back on and allow it to warm up for at least 15 minutes.
9. Turn the UV detector gain adjustment pot (See Section 11.3.7.2) clockwise to its
minimum val
ue. The pot should
click softly when the limit is reached.
10. Perform the UV Lamp Adjustment procedure described in Section 11.3.7.2 with the
following exceptions:
Slowly rotate
the lamp in its housing (up to ¼ turn in either direction) until a
MINIMUM
value is observed.
Make sure the lamp is pushed all the way into the housing while performing this
rotation.
If the PHOTO_DET will not drop below 5000 mV while performing this rotation,
contact TAPI Customer Service for assistance.
