Why output fades quietly
The failure mode is decline, not breakdown. Dust on the lens, a film on the gobo, a seal that has started to let in moisture — each takes a little output, and together they turn a bright IP67 gobo projector into a disappointing one without anything ever actually breaking.
- Take a reference photo at install, under the conditions it will run in
- Repeat it annually, same hour, same house lighting
- Log any cleaning or gobo change with a date
- Compare before assuming the unit has failed
How to clean without damaging coatings
Clean in the order the light travels: outer window, then the lens, then the gobo. Use a blower or a soft brush before any liquid, and only then a lens cloth with a drop of isopropyl — never a household cleaner, which will damage coatings in one go. Handle the gobo by its edge; fingerprints bake into the coating under a hot lamp.
- Remove loose dust with a blower or soft brush
- Wipe with a lens cloth and a little isopropyl only
- Never use a household cleaner on coated optics
- Handle the gobo by its edge only
When the image, not the lamp, is the problem
The gobo is the part that carries the image and the part most often blamed for a fault that is elsewhere. Check it against a light before assuming the optics have failed: a hairline crack or a patch of degraded coating shows up clearly when you tilt it. Keep the reference code so reorders are exact.
The half-yearly inspection
Heat and water are the two things that kill an IP67 gobo projector early. Check that ventilation paths are clear, that seals are still seated, and that the cable entry is intact. If the unit is in an enclosed void, measure the air temperature around it — the LED life figure assumes it is not cooking.
- Housing temperature after an hour at full output
- Seals and gaskets still seated and supple
- Bracket tight and the unit still on aim
- Cable gland intact and the drip loop in place
Seasonal and event checks
Seasonal checks are about duty cycle, not optics. Run it for the length of the event, at the hour it will run, and confirm it does not cut out. Clean the optics at the same time and you will start the season at full output.
Spares worth holding
The spares list is short because the failure modes are few. A spare glass gobo covers image damage; a spare control handset covers the most common support call; a recorded artwork reference covers everything else. Keep them together with the install record.
