Test of Eumig S938 Stereo with 200w lamp

[Paul Adsett]

Having completed the build of a 24 volt 250watt power supply to drive the 250w ELC lamp in my GS1200, it occurred to me that I could use the same power supply to drive a 200watt 24v ESC bulb put into my Eumig S938 stereo. I decided to do a quick test to see if this was a realistic possibility, and I as curious to see how it would perform.
I installed a ESC bulb into the 938 and connected it to my power supply. First thing I noticed was that the lamp housing cover did not quite want to fit on, seems that the ESC bulb has a slightly different shape, but it almost fit on and was close enough for a quick test. I ran the test with the Kodak Ektar f1.0 22mm prime lens fitted. Powering up the projector fan first, then a 1minute preheat of the lamp, and then switching to exactly 24v on the lamp, the 60 ins matt white screen was very bright and very white, IMO on a par with the standard 200w Elmo GS1200. I projected a 200ft reel and the picture was better than I have ever seen before on this machine - that extra brightness really pays off.
One thing I noticed was the heat build up in the lamp house area, and I think there is a need to improve lamp cooling with an extra blower somewhere.

But the test showed that an upgrade to a 200w lamp is a well worthwhile proposition on the 938, and a HID upgrade might be even better.

[Osi Osgood]

You would know these issues far better than l, but I was wondering, if the plastics used in the projector are for a lower heat lamp, could a 200 watt lamp cause permanent long term damage in the long haul?

[John Armer]

Osi, interestingly even the 150W lamp in those projectors create perhaps more heat than the manufacturers were expecting. On the Eumig S938 and S940 there's an extra plastic exhaust, connected to a separate lamp fan, that is positioned near the lamp and draws air away from it when the lamp is on. On well used machines, the plastic of this exhaust nearest the lamp softens and deforms slightly - I find it's a good way of identifying whether a machine has had a lot of - or little - use.

[Stuart Budd]

...and the picture was better than I have ever seen before on this machine - that extra brightness really pays off.

Thought didn't occur to be that image quality would improve too. An overall better viewing experience. But of course. Brightness equals detail and vibrance.

I was just thinking all these light kits were for reliability, longevity. Buy it forget it type thing.

Quality of image does make more sence.

[Paul Adsett]

The purpose of my experiment was to determine how an S938 would perform with a 200w ESC lamp powered by an external 24v power supply. The results were positive in terms of greatly improved image brightness and visual impact, on a par with the GS1200.
The major issue facing this kind of design modification is that of heat dissipation, which would be boosted by 25% over the original EFR lamp. As Osi has pointed out, construction wise, the 938 is no GS1200, and the cooling is not nearly as efficient as the GS. My brief test confirmed that the projector was getting uncomfortably hot, even after only a 200ft reel. The incorporation of a high velocity blower at the lamp house would be a necessity for any viable design upgrade.

As a word of caution here, I am not advocating that anyone run a 938 with a 200w lamp. You would almost certainly damage the projector.