Modify a carousel slide projector with LED

Nearly all projectors use halogen lamp for lighting, and some of high-end products chose xenon. They are continuous spectrum and high CRI. However, no matter halogen or xenon, traditional lamps are hot and difficult to cool, and are also low luminance. Fortunately, advances in the semiconductor industry allow us to choose some better products for partly replacing traditional lamp. Therefore, I can use a COB LED in my projector to take 3200k halogen lamp's place.

I did the program in July. And the first phase cost about $220 + half month. This phase is able to project a nice nice image, but still not good enough. Old Golden Navitar zoom lens limited the resolution, 100w LED is not powerful to work in bright room, ancient gears crushed when they were driven by motor. Obviously, a second phase improvement is necessary. My plan is adding 100 or 200 more walt LED, mounting a TTArtisan 50/1.4 lens and replacing new gears.

At first, I'd like to show some results from the first phase. Basically, 5000k is much more comfortable than 3200k while admiring slides. But unluckily, I didn't shoot any halogen example. All photos were slides projected on white wall and shot with my phone in 5500k WB setting without any editing.

These are some very lovely images, well done.

It would be great to give us a little information on your projector, maybe some shots of your setup including more information on the bulbs and where to get them.

I have an old Kodak Carousel projector with an odd sized bulb, so I'd be interested in setting it up with an LED bulb.

Robert Ley said:

These are some very lovely images, well done.

It would be great to give us a little information on your projector, maybe some shots of your setup including more information on the bulbs and where to get them.

I have an old Kodak Carousel projector with an odd sized bulb, so I'd be interested in setting it up with an LED bulb.

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I'm writing now. But I need to find some information, pictures or drawings to recall details.

Another really interesting application for LED lamps in a Carousel projector is for camera "scanning" of mounted slides. There's a fellow in the USA who reconfigured projectors with LED lamp, mounted an inexpensive Nikon DSLR with a macro zoom lens, pointed into the projector. A computer program would trigger the camera, and advance the slide tray. This would copy a complete Carousel in a couple minutes.
No fumbling with taking slides out of trays.
I'm not sure if these projectors are still being offered, last I witnessed one in action was 10 years ago. Still usually required some touching up with photoshop etc.

Obviously much lower power required than for projection.

MsLing said:

Basically, 5000k is much more comfortable than 3200k while admiring slides.

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That's very interesting! Will be looking forward to the description of the modified projector.

mshchem said:

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cool

First, I quote a figure from Kodak 4400's manual. Even though I exactly use Seagull 4400L, they are basically approximate. Kodak authorized Seagull to edit and manufacture Carousel projector. And the first phase focused on replacing light source and adding wireless remote control.


Fig.1


This picture show structure of Carousel's basic lamp module. Light source is an 82V 300W FHS halogen lamp with reflector. Light comes out and reflects on the cold mirror, passes condenser lens and absorbing glass and finally illuminates slide. But only lamp module will be discussed today. Kodak used to choosing "L" type optical path in their machine. I am not sure if this word right or not, but hope you can understand what I mean.

The first thing is that halogen. It needs to be pointed out that the lamp has a 152.5mm focal length, and the whole original optical system considered this when it was designed. And don't put an EXR lamp in this lamp module, or machine will be overheating.

The second component is a mirror. Theoretically it is a cold mirror, but I didn't test it. A typical cold mirror allows infrared pass and reflects visible light. So light comes into condenser will be "cooler", infrared radiation, which can heat object, is popularly known as "heat radiation" and over much heat is harmful to dyes in emulsion.

The third part is an optical block, includes condenser lens and heat absorbing glass. Projectors use critical illumination, so condenser focus an image of a light source on focal plane of slide. Heat absorbing glass cut the rest of infrared reflected from cold mirror to confirm slides' safety.


Fig.2

Fig.3

Cold mirror and heat absorbing seems can prevent heat form harming slides. However, as Fig.3, the transmittance curve of heat absorbing glass shows, it can't not cut all infrared and UV-A. And Fig.2 displays that halogen emit most of its power in infrared wavelength. Therefore, some infrared still leaks and heats slides and ultraviolet decomposes dyes. It explains why we can't project a slide in halogen projector for too long.

Happy new year! I will continue tomorrow.

On the topic of how much light is produced by 300W projector bulb (where mose energy goes into producing heat!)
"A 300W halogen projector bulb typically produces between 5,000 to over 7,000 lumens, with common figures around 5,950 lumens for general use, but specialized projector/stage bulbs can hit 7,800 lumens"

wiltw said:

On the topic of how much light is produced by 300W projector bulb (where mose energy goes into producing heat!)
"A 300W halogen projector bulb typically produces between 5,000 to over 7,000 lumens, with common figures around 5,950 lumens for general use, but specialized projector/stage bulbs can hit 7,800 lumens"

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At least Osram announced in datasheet that a FHS lamp is able to produce 650 lm and EXR produces 925 lm. I will contact with Osram.

Fig.4

Fig.5

I exhibit the overview about this modified projector. This machine uses a water-cooling light source because a semiconductor light cannot work in high temperature for long time or attenuation will happen. And yes, it's a Frankenstein now.

In the red circle of Fig.4 is a 12V3A DC power supply. Yellow circle is a 12V pump for circling water. And inside the blue one is a 120mm radiator and 120mm fan. I removed its tank when I removed the machine from the shelf so you can't see. The silver block is a constant current power supply for LED. And in Fig.5 you can see that I dig a big hole to allow tube and wires come out from lamp module. Kodak 4400L use screws to fix lamp module's top, as Fig.6 shows, but this is a Seagull, so I found it is way more different from Kodak's lamp module design. Seagull's engineers decided to use riveting and bending to fix it and it's the mean reason of why I solve it violently.


Fig.6


Fig.7

Open 4400L's case, on the top of Fig.7, from left to right we can see lamp module, clutch&changing module and lens module. And at the bottom of Fig.6, also from left to right, there are fan, temperature control resistor, motor and transformer. I didn't modernize them. I only add a remote control for forward and reverse, a motor controller and a new motor for driving lens. Modernizing fan, temperature control resistor, motor and transformer is possible but unnecessary. It will cost too much time and money.

Important tips: If you use Kodak 4400 or other Carousel projectors, it's unnecessary to open its case for modifying a LED light source. Kodak's design allows user directly pull lamp module out. But in Seagull, the cover plate inside machine produces a track with limiter and prevents user from directly pulling out lamp module.


Fig.8 Head and LED

I only talk about replacing lamp and add a wireless remote control. Kodak teaches user how to change motor in their service manuals. Replace lamp is quite easy, only need to remove the top of lamp module and MR13 mount, then you can get a lot more room in lamp module. I remember it's about 54-55mm high. After that, use pliers or saw or anything you like to create a hole on lamp module to contain pipes and wires. Remove the reading window I mark in Fig.9 can save a lot of time. If the hole is not big enough to contain pipes and wires, continue to use tools to expand it until it works well.


Fig.9

And in lamp module, there's a stand with a round hole for halogen lamp as Fig.1 and Fig.7 show. I used some silicone rubber to fix my LED and cooling on that stand. I also glued head and LED baseboard after applying silicone grease. It will be better if you fix hose and wires before glued LED on the stand, because acting in this narrow room will be hard. My LED, YSX-100TW/W45G14-Z3C, its electrodes touch lamp module's metal case, so I need to do some insulation measures to avoid short circuit. After that, put the top of lamp module back. At last, connect pump, radiator, tank and power supply, push the lamp module back and the projector can work.

TBH, from my professional perspective, the optical design after my modifying is ugly and flawed. But, considering the cost and benefit, it is balanced.