Harman Martin MAC Ultra Performance, Safety And Installation Manual

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Service and maintenance
21
Rotating gobo replacement
The MAC Ultra Performance uses specially designed borosilicate 3.3 rotating gobos. The gobos are a
custom size. Their external diameter is 37.5 mm +0/-0.2 mm (1.476 in. +0/-0.008 in.), and the image
diameter is 30 mm (1.181 in.). The gobo thickness is 1.1 mm +/- 0.1 mm (0.04 in. +/- 0.004 in.). The gobos
are manufactured in Borofloat 33 glass with a heavy matted aluminum coating.
Although the goboholders on Gobo Wheel 1 are different from the goboholders on Gobo Wheel 2, the actual
gobos are the same type and size and can be interchanged no matter which wheel they are installed on.
Replacement gobos must have the same dimensions, construction, materials and quality as the gobos
supplied as standard. Using gobos that do not meet this requirement – such as metal gobos – will very
probably cause damage that is not covered by the product warranty.
Optical components have fragile coatings and are exposed to very high temperatures. Handle and store
components with care.
See the MAC Ultra Performance User Guide (available for download from the product pages on
www.martin.com) for names, illustrations and part numbers of the gobos installed as standard.
Avoiding damage to gobos
Follow these precautions when handling, using and storing gobos:
• Do not use gobos with dark coatings on either side, as these will absorb heat – either directly from the
light source or reflected back from other optical components – and will not be durable.
• Do not use metal gobos in the MAC Ultra Performance: their durability may be reduced when used in this
fixture.
• Store all gobos in a dust-free environment with approx. 50% humidity.
• Wear clean nitrile cleanroom gloves when handling gobos.
• Avoid scratching coated and uncoated sides.
• Do not place a gobo with the coated side face-down on any surface.
• Avoid touching the other gobos when removing a gobo from a rack: the sharp edge of one gobo can
scratch the others.
• Keep gobos perfectly clean to reduce the risk of heat damage.
• When cleaning gobos, use a repeated dabbing action rather than a rubbing action. When rinsing, use
distilled or even better deionized water to avoid residue that will appear as drying marks.
• If possible, clean the coated side of gobos with dust and oil-free compressed air only. If the coated side is
contaminated with oil, clean with isopropyl alcohol and optics cleaning tissues.
• Clean the uncoated side of gobos with isopropyl alcohol or photographic quality lens-cleaner and optics
cleaning tissues.
• Do not try to clean gobos in an ultrasound bath, as this may cause delamination of the coating.
• Do not use acidic or alkaline cleaning solutions, as they will attack the aluminum coating.
• Correct gobo orientation is critical. Read the guidelines given later in this chapter carefully before
installing a gobo.