Cine Projector - LED Array Conversion

Introduction: Cine Projector - LED Array Conversion

This project is to upgrade and improve an 8mm cine projector by replacing the incandescent bulb with a LED array.
Aside from the fun of experimenting with LED arrays this project enabled me to convert some 8mm cine with less flicker and no risk of destroying the film by the heat from the bulb. (Being a Brit I shall use the term bulb rather than lamp)

Supplies

LED array 30-50 watts with LED driver
45x45mm heatsink
Short section of 13mm copper water pipe
Redundant bulb (for the base only)

Step 1: Study the Original Light Source

This bulb/lamp is typical of many cine and slide projectors of the era. Aside from being expensive to replace they obviously kick out a lot of heat. Anyone who has used a projector knows that the film is destroyed quite quickly if the film is stopped for more than a few seconds

Step 2: Let’s Look at the Bulb

This bulb is a Projector Bulb type A1-17 8v 50w with a P30s Base. It doesn't matter what bulb type it is. Its's only]y used for the base

Step 3: This Is the Base

This is the base. It's an easy way to mount the LED array and its heatsink

Step 4: The LED Array, to Be Used As the Light Source

This is the LED array with its driver. I chose a 30 Watt device bought online. The choice of power will be determined by how large a heatsink can be fitted.

Step 5: Add the Heatsink

The heatsink was bought online. It came from an old PC. The choice of heatsink is determined by the available space

Step 6: A Look at the Location of the Light Source

THis just shows the space for the heatsource. This will be different for different projectors

Step 7: Fitting the Heatsink

The heatsink is drilled with four holes to match those in the surround of the Array. I ordered a set of taps to cut the screw threads. It's wise to add some heatsink compound.

Step 8: Fitting the Base to the Heatsink

The base, less the glass neatly fits a piece of copper water pipe. I splayed one end and soldered the other to the base. I also trimmed off the wires from the centre of the base so that the lamp supply doesn't reach the heatsink

Step 9: A Secpond View of the Fixing

Here yuo can see the splayed end of the pipe

Step 10: Drilling the Heatsink

The Heatsink is now tapped with four M4 threaded holes

Step 11: Here's the Array Fitted to the Heatsink and Wired Up

As the title says here's the array fitted to the heatsink and wired to the driver. The lead solder to the two ears but you need to use a continuity tester to determine which is +ve and which -ve. Its not obvious

Step 12: Fitting the Heatsink to the Base

I've missed a video. Two of the splayed sections of the pipe are drilled and the heatsink also to accept two crews

Step 13: The LED Array Powered Up

This is the LED powered up. Don't look directly at it!

Step 14: The Temperature After 10 Minutes

The heatsink shouldn't get beyond 85deg. But this was without any cooling air

Step 15: The LED Array With Its Base

This clip shows how the base is fitted to the heatsink..I used self-tapping screws into the heatsink

Step 16: The LED Array in Place

This shows the Array and heatsink in place ready to be powered up

Step 17: LED Array Powered Up

This hows the Light in place but the cover needs to be fitted so that the telecine is not adversely affected by the stray light

Step 18: The Mods to the Cover

So as to allow the wires to the array to pass through the cover I cut a slot in the bottom of the cover.

Step 19: The Cover in Place

This shows the cover in place with the LED powered up. The cover doesn't fit perfectly but well enough

Step 20: The Final Result

This is a short clip of one of the reels. It's not a professional job but it's enough to decide what of the footage is worth spending more time and money on

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    11 Comments

    0
    thtc62
    thtc62

    Question 6 months ago on Step 20

    This looks a really useful project. I was just wondering if the parts that are screwed in could be stuck on instead? I haven't many tools and just want to replace the old a1/17 bulb as simply as possible. Thank you.

    0
    big-bill3
    big-bill3

    Answer 6 months ago

    Looking back the main parts that are screwed on are screwed to the heatsink. I suggest that are two options. One is to use a glue that will withstand the temperature of the heatsink. The other is to carefully choose the best combination of metal thread screw and hole size such that you can cut a thread in the heatsink.
    A good thermally conducting glue should work to fix the array to the heatink. You’ll have to experiment with methods of mounting the heatsink to the bulb base. I was fortunate to have a spare but defunct bulb

    0
    thtc62
    thtc62

    Reply 6 months ago

    Thank you that is very helpful. I am going to use the old bulb base I have and the copper pipe you suggested. Along with thermal glue. Fingers crossed it all works out. Just waiting for heatsink to arrive from China!

    0
    big-bill3
    big-bill3

    Reply 6 months ago

    Do you have the led array? I ask because I have some spares

    0
    thtc62
    thtc62

    Reply 6 months ago

    Hi, yes thank you I bought one from eBay. I'm going to try and follow your instructions exactly.

    0
    big-bill3
    big-bill3

    Reply 5 months ago

    Following my instructions exactly may not work. It’s the principles that matter. You will have to adjust things to fit your projector and the size of the heatsink etc

    0
    videonet
    videonet

    Question 6 months ago

    hello, thanks for your instructions. I ask you why do you not use a dimmer so can manage the bright of the led. Also what kind of led temperature use? (3200 or 5400 )

    0
    big-bill3
    big-bill3

    Answer 5 months ago

    Thanks. I didn’t see the need for a dimmer. I don’t know enough about how to drive the led array so I’m not sure where it should go in the circuit. As for temperature I think I opted for the highest available. My eBay history doesn’t go back far enough to trace the purchase but it would have been cool white. It’s your choice

    0
    big-bill3
    big-bill3

    6 months ago

    This shows the screws into the heatsink.

    C4A51006-B281-4A92-AA4F-28556CDFE94F.jpeg981132A5-34AD-4E9B-91F3-1CF9BA6D52E4.jpeg
    0
    big-bill3
    big-bill3

    6 months ago

    The other complication I met was that it was not obvious to see which was the positive connection to the array and which the negative. I used a test meter to trace the connection across the array. I'm not sure what would happen if it’s reverse connected to the supply and it’s hard to get a sensible reply from the Chinese supplier