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Topic: Eumig 940 Stereo Projector Sale

James N. Savage 3
Phenomenal Film Handler

Posts: 1375
From: Washington, DC
Registered: Jul 2003

posted May 14, 2013 01:28 PM

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I'll chime in as well on the Bauer T610. Its been my primary projector for many years now, and it is a very professional performer. No prjection booth needed, with just barely enough mechanical sounds to remind you that your watching real film. [Smile]

[Smile]

James.

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Paul Adsett
Film God

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From: USA
Registered: Jun 2003

posted May 14, 2013 06:58 PM

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Alan, one thing I found on my 938 is that the lamp was only getting 14 volts instead of 15 volts. This was with the transformer setting at 117 volts. So I moved the tranformer tap to the 110 volt position and this brought the voltage up to 14.9 volts, which made a big difference in screen brightness. It could just come down to winding tolerances on the transformer., or perhaps Eumig deliberately under ran the lamps to prolong life. Whichever I want full screen brightness even if the lamp life is shorter.

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The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
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Eumig S938 Stereo f1.0 Ektar
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Martin Dew
Expert Film Handler

Posts: 204
From: Henley-on-Thames, UK
Registered: Jan 2017

posted May 24, 2017 04:15 PM

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Dragging up an old thread here! Paul, do you know how much less life in percentage you're getting from changing the transformer taps on your S938? I'm assuming you might have measured this over time. What change would need to be made to a UK based machine to achieve close to 15v output?

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Andrew Woodcock
Film God

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From: Manchester Uk
Registered: Aug 2012

posted May 24, 2017 06:17 PM

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Even half a volt over the stated and nominal 15vac, will drastically reduce lamp life just as in the same manner reducing the voltage marginally, will drastically increase the life by way beyond the predicted manufacturers stated lifespan of 50 hours.

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"C'mon Baggy..Get with the beat"

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Martin Dew
Expert Film Handler

Posts: 204
From: Henley-on-Thames, UK
Registered: Jan 2017

posted May 24, 2017 06:26 PM

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But what is 'drastic', Andrew? 70%? I'm trying to get a sense of the trade-off that Paul believes to be acceptable to achieve a brighter image. He must have some evidence, even anecdotal. It might be worth it.

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Dominique De Bast
Film God

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From: Brussels, Belgium
Registered: Jun 2013

posted May 24, 2017 07:08 PM

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Several projectors have a low/high lamp button and following the models it is said that the low position can extend the bulb life from three to five time. I have no idea if this is a king of lab tests statment or if it really makes that difference in normal use.

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Dominique

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted May 24, 2017 09:07 PM

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The thing is Martin, when correctly focussed through the tiny gate, at 15v exactly with a fast lens, these lamps can and do produce an amazingly bright image on screen from even good lengthy throw distances and at quite large screen sizes.
For whatever the reason, the Eumig pairing just doesnt seem to make anything like the most of this lamp output.
This may be down to the lamp holder position and gate design, speed of pull down, shutter blade angles etc etc, I do not know, but what i do know is you would not believe it is the exact same lamp fitted in other machines that use this exact same lamp.
I think over exciting the lamp would just be masking the real issue here with these machines and to a certain extent, we just have to accept them for what they are if your transformer tap settings are set correctly for the correct regional supply voltage.

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"C'mon Baggy..Get with the beat"

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Paul Adsett
Film God

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From: USA
Registered: Jun 2003

posted May 24, 2017 09:40 PM

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Just to clarify, I am not recommending over-volting the lamp, just adjusting the transformer tapping to get the correct 15.0 volts at the lamp terminals. Presumably this will not degrade the normal lamp life.
With the normal 117v setting for US mains, my lamps were only getting 14.0 volts, lasting forever but were pretty dim. My preference is to get a much brighter picture with normal lamp life.

--------------------
The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted May 24, 2017 11:54 PM

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I completely agree Paul regarding certainly not going beyond around .3 or .4 of the recommended voltage to the lamp. Not only because of the affects this may have on lamp life, but more due to ensuring all feeds from the transformer secondary windings are within the designed output tolerances to protect the rest of the machine.

It would be helpful to know what voltage is currently present on your lamp socket Martin to see if you are getting anything like the recommended 15v that is supposed to be there?

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"C'mon Baggy..Get with the beat"

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Brian Fretwell
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From: London, UK
Registered: Jun 2014

posted May 25, 2017 02:54 AM

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I have been told that 10% under voltage doubles the lamp life. I would assume that 10% over might halve it. For 15v that would be 1.5v though so 0.5v could take about 10 hrs off lamp life. For a special show or a dark print it might be worth it.

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Andrew Woodcock
Film God

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From: Manchester Uk
Registered: Aug 2012

posted May 25, 2017 02:58 AM

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That sounds about right to me also, as an average from a guess based on some experience with this,I'd say Brian.

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"C'mon Baggy..Get with the beat"

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David Hardy
Jedi Master Film Handler

Posts: 955
From: Johnshaven Village , Montrose, Scotland
Registered: Jan 2015

posted May 25, 2017 05:49 AM

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I would like to state this has been a very interesting thread.

We used to under ampage our xenon lamps at the cinema sometimes
in order to increase the life of these expensive items.

There was no real significant loss in screen brightness.

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" My equipment's more important than your rats. "

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David Roberts
Master Film Handler

Posts: 405
From: Suffolk. England
Registered: Apr 2004

posted May 25, 2017 12:08 PM

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I always run my Bauers at the reduced lamp setting at home and can honestly say I cant remember the last time I had a lamp blow.
They just seem to last forever. my screen is just 4 foot wide,so the brightness level of picture is very good at the reduced voltage.

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted May 25, 2017 01:38 PM

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On a 4ft screen, even the lowest lamp setting from a 150w Xenophot will be plenty bright enough in all but stark daylight conditions.

I use quite a large screen and enjoy all the brightness levels I can get to fully illuminate it even in pitch black conditions.
Having said that, I never feel I need brighter on two blade mode with fast lenses even filling this sized screen in the dark.

The 150w Xenophot is all you could need in anything other than a mansion with a dedicated cinema room of its own to my way of thinking.

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"C'mon Baggy..Get with the beat"

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Martin Dew
Expert Film Handler

Posts: 204
From: Henley-on-Thames, UK
Registered: Jan 2017

posted May 27, 2017 01:47 PM

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Well...John White just put a new lamp in my S938 (and fixed my rotary switch lamp problem). So my image is significantly brighter with new lamp. I will now test on a larger screen and report back. And next time I have a brightness issue, I will at the very least swap out the lamp before troubleshooting further!

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted May 27, 2017 03:20 PM

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[Smile]

[Smile]

[Wink]

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"C'mon Baggy..Get with the beat"

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