5. Maintenance
5.8Changing the mercury lamp
4.Set the range selector to SHORT and zero the recorder.
5. Set the range selector as follows:
254 nm, range 1
280 nm, range 0.2
6.Turn Zero fully clockwise.
Response 8 mV or greater: the lamp is operating properly and the optical system is clean.
Response 0 mV or very close to 0 mV: Contact a GE Healthcare representative.
Response less than 8 mV but not very close to zero: check that the cell and filter is clean. If fault persists, the filter or lamp may require changing (see Section 5.7).
The low pressure mercury lamp has an expected lifetime of approx. 8000 hours. Before changing the lamp, carry out the tests described in Section 5.6. If the tests indicates an aging lamp, proceed as follows.
l.Disconnect the control unit from the mains supply and disconnect the optical unit from the control unit.
Warning: The control unit must be disconnected from the mains and from the optical unit. If the
2.Remove the cell holder.
3.Remove the two screws and locking washers which secure the case of the optical unit to the bottom of the chassis.
4.Loosen the two Philips screws until the top of the case can be lifted clear of the catches.
5. Pull the case forward, and remove it (Fig. 14).
Lamp Screw
Screw
Stop ring
Fig. 14. Optical unit interior with lamp driver circuit board removed
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