Cine Projector - LED Array Conversion

by big-bill3 in Workshop > Home Theater

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Cine Projector - LED Array Conversion

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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)

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

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

This Is the Base

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

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.

Add the Heatsink

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

A Look at the Location of the Light Source

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

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.

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

A Secpond View of the Fixing

Here yuo can see the splayed end of the pipe

Drilling the Heatsink

The Heatsink is now tapped with four M4 threaded holes

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

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

The LED Array Powered Up

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

The Temperature After 10 Minutes

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

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

The LED Array in Place

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

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

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.

The Cover in Place

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

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