Weird light levels

[Armand Daiguillon]

I do have a light meter and there is definitely the issue with two identical projectors with 2 brand new bulbs, i get significantly less from one than the other. The manual x y z calibrations (these are Solaria One's) have given the best they could - aside from raising the power to the bulb, is there any other setting or anything I should check that could cause this lesser light on this projector ?

Thanks !

[Carsten Kurz]

Can you just switch over the bulbs easily to see what happens?

[Ioannis Syrogiannis]

Just trying to imagine what factor does or might have done a difference, so take my words with a pinch of salt:
Apart from the obvious, different values filled for the same amount of energy, could it be an issue with what comes between the lamp/projector and the eye or light meter?
Lenses' throw ratios, specs and condition, contrast aperture (if available on ones, I know they are on One+ and 2210), port window and screen gain (higher, lower, worn) combined with off centered projector?
All that, especially combined, could give widely variated results with the same lamp on the same projector and wattage.

[Miguel Moreno]

I had a similar problem. After checking the equipment and comparing it with others, I realized the problem stems from the prism. It breaks inside, so it needs to be replaced.
In this case you have to call tech service.if that is the case.

[Gordon McLeod]

I suspect that you are experiencing the same issues we have had with the pot metal casting that the reflector assembly is held in has warped slightly
I ended up having to slot out the mounting screws so I could get it to produce a decent light.

[Ryan Gallagher]

Since you’ve confirmed a light level difference at 100% via two meter readings (presumably taken at the same throw distance and region of the screen). It is no longer just about the UI displaying weird light levels on the TPC.

Assuming this problem did not exist before the new lamps were installed…. would agree your next step is to suspect a bad lamp. Ether swap them across as Carsten suggested and see if the problem moves or stays with the projector, or try a different new one in the dim unit.

There definitely may be other factors at play but starting with lamp seems like the easiest to rule out. Perhaps one had a lamp adapter installed for a different model lamp prior that got missed? (just an example).

[Leo Enticknap]

Thanks Ryan. As you note, we've ruled out a bad sensor or metering issue, and established that we are now looking at an actual light level problem.

aside from raising the power to the bulb, is there any other setting or anything I should check that could cause this lesser light on this projector ?

If it were me sent on a troubleshooting call with this reported fault, I'd tackle it by following the light path from its origin (lamp power supply) to destination (the screen), starting with the easiest things to check and progressing through the more difficult things to check. The following is in the order that I personally would rank from easiest to check to the biggest pain in the bum, but others may have other thoughts on this, and the model of projector might vary the ranking, too.

• Triaxial (X, Y, and Z) alignment; but you note in your opening post that you've looked at that and ruled it out.
• Open up the lamphouse. Is there anything obviously wrong? Damage to the reflector coating, the UV filter, or the cold mirror (steers the light through 90 degrees from the lamphouse into the light pipe), or blackening of the lamp envelope, for example? If nothing pops out at you...
• Porthole glass. It is dirty, and/or with a thick layer of dust on it? You'd be surprised how much light a bad port glass can drink.
• The lamp, by swapping (per Ryan)
• Lens. Swap with another house's lens, if possible, a house that uses one of the same model. Does the light loss stay in the original house, or move with the lens?
• The screen. Is it old and getting yellowed compared to the other one? Maybe try pointing a flashlight at it and taking a reading, then the same flashlight from the same distance in the other screen. Ensure that ambient light levels in the house are comparable when doing so (house lights on feature preset).
• The lamp power supply. Different manufacturers have different suggested procedures for checking performance, which usually involve using a multimeter to measure output current with the lamp running (potentially dangerous).
• Miguel's suggestion: damage to the light engine optics. Depends on how easy it is to eyeball the prism. Depending on the projector, you might need to take the light engine out of it.
• If the projector has one, the fold mirror (that steers the light from the front of the light pipe into the light engine)
• The light pipe and integrator rod (likely the most difficult thing to check, because significant disassembly is needed to get inside it).

[Marco Giustini]

Are the screens the same type, that is, are they both matte white (1.0 gain) or both high gain or both silver etc?

I'm just wondering if a high gain screen is involved here and what you see is the result of different angles, hotspots etc.