​​​​​​Rotating gobo replacement

​Rotating Gobos

The rotating gobo wheel in the ERA 800 Performance has six rotating gobos that can be selected, indexed (positioned at an angle), rotated continuously and shaken (bounced). The gobo wheel itself can also be scrolled continuously or shaken. Gobo selection and control type (indexing, continuous gobo rotation, gobo shake or continuous gobo wheel scrolling) are selected on channel 13. Depending on what is selected on this channel, the gobo indexed angle or gobo rotation speed are set on channels 14 and 15 with 16-bit control resolution.

The standard gobos are shown in the correct order in Figure 2. All gobos are interchangeable, but Gobo 3 (Limbo) is fused glass and has a special gobo holder.​

Static Gobos

The static gobo wheel in the ERA 800 Performance has seven static gobos. The static gobo wheel can be scrolled continuously or shaken. Gobo selection and control type (indexing, continuous gobo rotation, gobo shake or continuous gobo wheel scrolling) are selected on channel 6. Depending on what is selected on this channel, the gobo indexing angle or gobo rotation speed are set on channels 7 and 8, where 16-bit control is available.

The standard gobos are shown in the correct order in Figure 3.​

The ERA 800 Performance uses specially designed borosilicate 3.3 rotating gobos with a heavy matted aluminum coating. All gobos are interchangeable, but replacement gobos must match the dimensions, construction and quality of the gobos supplied as standard. The gobos are a custom size: 30.0 mm +0/-0.2 mm external diameter, 25 mm image diameter.​

Optical components have fragile coatings and are exposed to very high temperatures. Handle and store components with care.

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 ERA 800 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.

​Opening the head for access

To open the head for access to the rotating gobos:

1. Disconnect the fixture from power and allow to cool for 30 minutes.

2. Place the fixture on a suitable work surface.

3. See Figure 10. Apply the tilt lock A.

4. Remove the four retaining screws B from one of the head covers and lift the cover away from the head slightly. Press the retaining clip C on the cover’s safety wire in towards the head chassis, slide the clip until you can remove it, and then remove the safety wire and head cover completely from the fixture.

5. Remove the other head cover in the same way.

When closing the head, follow the above procedure in reverse. Check that the head covers are held securely after you have reinstalled them, and release the tilt lock before reapplying power or packing the ERA 800 Performance in it's flight case.

Replacing a rotating gobo

Important: 

Different screw sizes and types are used on the modules and components inside the head. Make sure that you do not mix them up. Apply a small quantity of Loctite 222 to the threads of all the screws mentioned in this section when you reinstall them.

To replace a rotating gobo:

1. Remove both head covers as described in the previous section.

​2. See Figure 11. Position the head so that the effects cooling fan A is facing you. You are now looking at the bottom of the head.

3. Unplug the effects fan connector B, remove and keep the fan’s two retaining screws C and remove the fan from the head.

4. See Figure 12. Bend the effect wireset cable ties at A open.​

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​​5. Locate the effects module connector B and disconnect it from the PCB on the left of the head. Let the connector and wireset hang free.​

6. See Figure 13. Rotate the head through 180° so that you are looking at the top of the head. Remove the six screws (arrowed) from the effects module retaining plates and keep the plates and screws for re-use.​

7. See Figure 14. Slide the effects module carefully out of the head. If any wires or components become caught, especially on the module above, move them out of the way.​

8. Place the effects module on a clean work surface with the rotating gobo wheel facing upwards.​

9. See Figure 15. Note the position of the reference marks in the gobo drive wheel A and goboholder B. Note also the position of the goboholder positioning magnet C and gobo wheel positioning magnet D. Each time you remove a goboholder from the wheel, turn the drive wheel (twice if necessary) until the marks exactly line up.

We recommend that you only remove one goboholder at a time. Avoid turning the drive wheel while a goboholder is out of the gobo wheel. This will keep the gobos in their correct orientation, avoiding the need to reprogram cues or adjust gobo positions in the fixture because a gobo orientation has changed during service. Note that if necessary you can adjust the home positions of rotating gobos at any time using the SERVICE → CALIBRATION menu in the control panel.​

10. See Figure 16. With the reference marks lined up, lift the outside edge of the goboholder up slightly and pull the goboholder out of the gobo wheel. Note how the goboholder tongue (arrowed) engages in a recess in the gobo drive wheel. You will need to reinstall the goboholder with the tongue in the same position in the drive wheel.​

11. For details of replacing a gobo in a goboholder, see the next section of this manual.

12. When reinstalling a goboholder in the gobo wheel, use the above procedure in reverse as a guide.

​Do not apply lubricant to the goboholder or drive wheel.

Line up the reference marks in the goboholder and gobo drive wheel and push the tongue correctly into its location in the gobo drive wheel when you install the goboholder. Check that the goboholder is held securely in the wheel after you have installed it.

Installing a gobo in a goboholder
All the rotating gobos in the ERA 800 Performance are held in their holders by springs and can be removed from their holders as described below.

Note that the fused glass gobo Limbo (Crystal) has a specially designed goboholder and spring to cater for the extra thickness of the gobo. Fused glass gobos, their goboholders and their retaining springs are not interchangeable with the other gobos and goboholders.

Make sure that you install gobos facing in the correct direction, or they may suffer heat damage. The orientations shown in Figure 17 are correct in most cases, but consult your Martin dealer or gobo supplier if you are in any doubt about the orientation of a specific gobo type.​

In the ERA 800 Performance:

The side of the goboholder with the gobo retaining spring faces towards the LED light source.
The side of the goboholder with the teeth faces towards the front glass.
With the goboholder placed teeth down on a clean surface and the gobo retaining spring facing upwards as shown in Figure 18, gobos in the ERA 800 Performance must be installed as follows:

The shiny side must face upwards towards the spring in the goboholder. The white side must face downwards.
Images or text on gobos must appear correctly (and not flipped left to right) when looking down at the goboholder from the side with the spring.
The textured side of textured glass gobos must face upwards. The flat side of the gobo must face downwards so that the gobo sits flat in the goboholder.

Gobo alignment

See Figure 18. Note the position of the alignment marks (arrowed) on goboholders and gobos. Install gobos with the alignment marks next to each other.

Gobo replacement procedure

Avoid getting grease from your fingers or dirt onto gobos. Hold gobos by their edges only. Wear nitrile cleanroom gloves when handling gobos.

To replace a gobo in a goboholder:

1. See Figure 19. Place the goboholder on a clean surface with the shiny side of the gobo facing upwards. Note the position of the bend (arrowed) in the end of the gobo retaining spring. Using a plastic lever to avoid scratching the gobo, lever the end of the retaining spring out of the groove in the goboholder and lift the retaining spring out of the goboholder.

2. Turn the goboholder teeth side up and let the gobo fall out of the holder onto a clean, soft surface. Put the goboholder on the surface teeth side down again.

3. Holding the new gobo by its edges, insert it into the goboholder with the alignment marks on gobo and goboholder oriented correctly and with the shiny side facing upwards (see Figure 18). Check that the gobo is fully seated in the holder.

4. Insert the retaining spring into the goboholder and press it into its groove in the goboholder. Check that the spring is pressed as flat as possible against the gobo and that the gobo is held securely in the goboholder.

5. Reinstall the goboholder in the gobo wheel using the section above “Replacing a rotating gobo”.

6. When service work is finished, reinstall the head covers as described using the section above “Opening the head for access”.