HP 8168E User Manual page 237

Cleaning Fixed Connector Interfaces
A few instruments, such as the HP 8158B, have xed connector interfaces. Generally, avoid
cleaning this kind of interface, because it is dicult to remove any used alcohol or lint from the
input of the optical block. Keep the dust caps on the interfaces unless it is in use.
If there is dust on the interface, try cleaning it using compressed air.
If there is uid or greasy dirt on the interface then contact Hewlett-Packard, where trained
personnel can open the instrument and do the cleaning. Never open the instrument to clean the
optical block yourself, because the optical components can be easily scratched or misaligned.
Cleaning Optical Glass Plates
Some instruments, for example, the optical heads from Hewlett-Packard have an optical glass
plate to protect the sensor. Clean this glass plate in the same way as optical lenses (see \Cleaning
Lenses").
Cleaning Physical Contact Interfaces
Remove any connector interfaces from the optical output of the instrument before you start the
cleaning procedure.
Cleaning interfaces is dicult as the core diameter of a singlemode ber is only about 9
generally means you cannot see streaks or scratches on the surface. To be certain of the degree of
pollution on the surface of your interface and to check whether it has been removed after
cleaning, you need a microscope.
Warning
Never look into an optical output, because this can seriously damage your eye sight.
To assess the projection of the emitted light beam you can use an infrared sensor card. Hold the
card approximately 5 cm from the interface. The invisible emitted light is projected onto the card
and becomes visible as a small circular spot.
1. Clean the interface by rubbing a new, dry cotton-swab over the surface
Preferred
using a small circular movement.
Procedure
2. Blow away any remaining lint with compressed air.
Use this procedure particularly when there is greasy dirt on the interface:
Procedure for
Stubborn Dirt
1. Moisten a new cotton-swab with isopropyl alcohol.
2. Clean the interface by rubbing the cotton-swab over the surface using a
small circular movement.
3. Take a new, dry soft-tissue and remove the alcohol, dissolved sediment and
dust, by rubbing gently over the surface using a small circular movement.
4. Blow away any remaining lint with compressed air.
m. This

Cleaning Procedures E-11