Bio-Rad Model 550, Ultramark, and Benchmark Microplate Reader Accessories - Manual (Page 31)

Section 5
Instrument Service by the User
Caution: Electrical shock hazard! Always disconnect the instrument from
the AC power source before opening the service compartment.
Caution: The lamp may be very hot! Use caution, and allow the lamp to
cool before attempting service.
5.1 Installing Interference Filters
1. With the power off, open the rear cover of the instrument by sliding the release latch
on the top rear of the unit toward the rear of the unit.
2. Locate the filter wheel between the lamp and the left side of the instrument. Note that
the filter wheel has four filter positions.
3. Rotate the filter wheel until the desired filter is at about the 2:00 o’clock position.
Grasp the filter firmly with the thumb and the index finger of your right hand and
rotate the filter counter-clockwise 90° to remove it from the filter wheel.
4. Install the new filter by holding the filter between your index finger and thumb of
your right hand. Rotate the desired filter position in the wheel to the 2:00 o’clock
position. Line up the two prongs on the filter with the two slots in the filter wheel.
Turn the filter 90° clockwise to install.
5.2 Changing the Lamp
1. Open the rear cover of the instrument by sliding the release latch on the top rear of
the unit toward the rear of the reader.
2. Remove the two screws that hold the black lamp cover in place. Lift the cover up and
away from the instrument.
3. Press down on the spring wire that holds the lamp in place. This will allow the lamp
to be pulled free from the lamp housing.
4. Holding the ceramic base in one hand and the lamp housing in the other, carefully
pull the lamp free of the base.
5. Carefully insert the new lamp firmly in the ceramic base. Apply even pressure when
inserting the lamp so that the bulb does not become misaligned in the reflector housing.
Also, be careful not to touch the bulb or the inside of the reflector housing during installation.
6. Position the lamp in the bezel and hold the lamp in this position until it is secured with
the spring wire.
7. Replace the lamp cover.
8. Close the rear cover.
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