GS1200 MKIII 250W conversion

[Graham Ritchie]

You will certainly need a small light weight transformer if you are going to use one inside a GS1200. The GS1200 is "hernia material" one might say without adding more weight to those things

[Paul Adsett]

Switching power supplies appear to be much smaller and lighter than an equivalent magnetic transformer. Switching power supplies actually provide a DC output for LED strip lights. 24volts DC should have the same heating effect on a resistor (incandescent lamp wire) as 24Volts AC, as AC voltage is actually an RMS value. A DC current going to the lamp would also have the advantage of eliminating all hum associated with the projectors lamp circuit.
But the question remains can a 24v 300Watt switching power supply be used to power a 24v 250w ELC halogen lamp?

https://power.sager.com/msp-300-24-2...SABEgIOuvD_BwE

[Phil Murat]

Normaly that should work Paul.
I have an other link for somebody in a french forum who built a circuit (which works as a switching unit) and to power a 24V / 250w halogen bulb too , however this is in French language. The idea is the same :

https://www.astuces-pratiques.fr/ele...ogene-24v-250w

Here is an other link which shows a very compact and similar one (very complete datasheet) :

file:///C:/Users/33662/AppData/Local/Temp/SMPS300R%20Datasheet.pdf


https://www.audiophonics.fr/fr/alime...v-p-12848.html
(Sorry , this is in French too, you can download "Datasheet" in English language in "Telechargement" (Downloading) Tab)

Hope this helps

NB:

Product decribed in last link comes at 79Euros (VAT included). This is expensive for such a circuit. I assume you can get same somewhere for half price at least, providing it is built with FR4 (Epoxy) board......

If somedy needs to built a self made "switching power supply", don't forget it is essential to use "High Frequency" (Low ESR) Electrolitic Capacitors

[Paul Browning]

Just find a disco light that uses a 24v 250 watt lamp, they use toroidal power supplies, like a dougnut ring bolted to the back of the unit, check out the martin lighting range, acrobat etc, these are utra reliable, and simple retro fit into a box.............

[Thomas Knappstein]

The best Solution is a Transformer from an old Slide Projektor wich works with a 250W Lamp. So this Transformers are not as big as the one in the GS 1200 and they have most two pic ups on the secondary Side, so you can use the original low and High Swich of the Elmo and pre- heating is working too.

[Paul Adsett]

Thanks Thomas - the same solution that Graham uses. But how do I get a list of slide projectors that use the ELC lamp?

[Thomas Knappstein]

Hi Paul! It isn´t important that the slide Projektor is working with an ELC Lamp. Most of them have the 24V/250W Base Pin Halogen Lamp wich is working in a condeser lens System. Those ones you can use too. You have to whach out for slide projectors with 250W halogen Lamp and low High swich for the lightoutput. Thats all. Here on Ebay Germany i have found some ones, but they are not very cheap.