8mm Forum: 16mm 24v 250watt instead of 15v 150watt

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Topic: 16mm 24v 250watt instead of 15v 150watt

Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 24, 2015 09:26 AM

Can i put a 24v bulb in my Eumig S940 instead of the original 15v 150w? I happen to have a lot of 24v bulbs and no spare 15v (I know that the pins are different, but maybe i can do something about that)

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 24, 2015 09:33 AM

Hi Harm,

A 24V, 250W bulb installed where a 15V bulb belongs will give 15V/24V (squared) of the wattage the 24V bulb was meant to produce: (about 40%), or 100W

I'm not sure it would even light up, and if it does it would probably be more red in color than white.

The fact that it's a 16mm bulb would probably make things even worse: the geometry of the filament would be wrong for the Super-8 aperture and an even smaller fraction of the light would get to the screen.

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All I ask is a wide screen and a projector to light her by...

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 24, 2015 02:25 PM

Thanks for your reply Steve! Actually the 24v bulb did light up, so that wouldn't be a problem, the 100w doesnt bother for now because I have to go through miles of film just to check them, not for viewing purposes at this moment.

But maybe I have another problem... I put in a 15v 150w spare (my last one) when the old one burned but the 'new' one (probably new old stock) also burned almost immediately (it turned black within a few minutes). So i might be having a problem somewhere else.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 24, 2015 04:06 PM

Hmmmmm...

Can you measure the voltage going to the bulb?

The simplest explanation for frying the 15V bulb is the voltage is too high.

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All I ask is a wide screen and a projector to light her by...

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003

posted March 24, 2015 08:23 PM

quote:
I know that the pins are different, but maybe i can do something about that

Is it?

I have plenty EJL and ELC (24v) and my bare eyes justify they have the same pins with EFR (15v 150w).

Can someone clarify this?

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Winbert

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Dominique De Bast
Film God

Posts: 4486
From: Brussels, Belgium
Registered: Jun 2013

posted March 25, 2015 12:27 AM

Winbert, I have the same interrogation you have.

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Dominique

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Flavio Stabile
Jedi Master Film Handler

Posts: 707
From: Roma, Italia
Registered: Feb 2005

posted March 25, 2015 03:11 AM

Hi Harm,
when you say "almost immediately" you mean after just few seconds or some minutes?
I had a similar problem (on a different projector) in the past with a lamp that just burned after some minutes and I didn't realize that the fan belt was broken so the lamp didn't receive ventilation anymore...

Flavio

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 25, 2015 10:01 AM

Hi Flavio, yes the belt is intact, the fan is spinning when I turn on the bulb. Steve, I am going to measure the voltage.

Well the pins on my 24v bulb are definitely different than the ones on the original 15v. More 'thicker' and 'shorter'. The ELC and ESC bulbs I have here have other pins and don't fit in my 940. See picture, on the left what fits (EFR?), on the right the 24v (in this case a ESC).

...luckily I found another 15v 150w EFR in the wrong box :-)

Here 4 different bulbs, from left to right: EJM,ELC,EFP,ESC (24v 200w). Only the EFP type fits in my S940:

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Dominique De Bast
Film God

Posts: 4486
From: Brussels, Belgium
Registered: Jun 2013

posted March 25, 2015 12:18 PM

Well, I have never come accross a different pins model ! I've used several different makes and lamps from 12v100 watts to 24v250 watts and they all could fit the normal bulbholders found in the projectors. Maybe someone could explain why there is a difference on the bulbs seen on the picture ?

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Dominique

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 25, 2015 01:54 PM

i have had many super-8 and 16mm projectors and the bulbs for the super-8 were always different than the ones for my 16mm. I don't know better :-)

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1632
From: California
Registered: Aug 2007

posted March 26, 2015 07:33 PM

Turning black within minutes could also be too low of a temperature for the halogen process to be activated, although if it's hot enough to incandesce, I'd think you'd be OK.

Halogen process being that it's so hot that the halogen gas prohibits filament vapor from re-depositing on anything but the filament. So I'm guessing insufficient heat, and run that bulb at full voltage and who knows - it might clear up?

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 29, 2015 05:38 AM

I measured the voltage directly and it is 21 volts. But I found another 15v and it still burns.

Is it normal that the lamp turns red?

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 29, 2015 05:54 AM

since power is proportional to voltage squared, you are pumping almost 300 watts out of that 150 Watt bulb and overheating it.

(It explains why the 24V bulbs work too..)

Does your machine have settings for different input voltages?

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 06:00 AM

Why is it 21v and not 15v as it should be?

As Steve asks, is the transformer set correctly??

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

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 29, 2015 06:18 AM

How can I find out? The projector worked for years with the old bulb. Input voltage is set to 220 which is correct, doesn't seem to have any other ways to change the input of the lamp.

I thought 21v is pretty correct because of resistance. I measured it directly with my meter. But I am i no way an expert on electronics. Heck I sold a portable xenon Hokushin once which I thought was faulty just to learn that the buyer had fixed it in a few minutes... Here are some pics:

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 06:44 AM

The voltage to the lamp connector should only ever be 15v plus or minus around one volt.

If this machine has worked fine for years then suddenly now has this fault of supplying 21v to the lamp connector, I do not know how this could be possible if the setting on the transformer is set correctly for your region.

I would have to trace the lamp circuit back to the transformer using the service manual if this was happening on my own machine.
I have a S938 myself which is a similar machine but unfortunately I have no service manual for it as I have never needed one to date on my own machine.

Typically the lamp circuit is very simple and just originates from two tappings on the transformer with one leg diverting off through the lamp switch. If this is the case here, there is nothing in circuit that can suddenly increase the voltage by around 40% except the transformer itself. Maybe you could find the lamp tapping on the transformer and measure the voltage there to see for sure that it's still 21v. Be very careful though placing probes near to the transformer when working live. You can easily damage your machine if your hand with a multimeter probe in it happens to slip off the correct terminals or worse still electricute yourself! Be warned!!

My machine has recently developed one or two minor flaws but Paul Adsett has kindly advised me on that, so as it stands I still won't be buying one just yet.

If you do choose to go down this route,the service manuals are available from Old Timers Cameras in London.

There are two for this model, one for the projector and one for the amplifier electronics.

I would not be using the machine while you have this high voltage present at the lamp circuit as you are just going to keep blowing the correct and only lamps that can be fitted correctly to this machine which is an A1 232 15v 150w lamp.

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

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted March 29, 2015 06:53 AM

Hi Harm,

Something has gone wrong here:

for the 150W bulb to operate at 15V from 21V through resistance, the resistance would have to get rid of (21-15)/15x150W, or 60W. That's a lot of heat.

I've measured the lamp voltage on an Elmo ST-1200 (also 15V, 150W) with the bulb out: maybe 16V?

Your voltage setting does look correct. It's as if there's some short circuit somewhere.

I'm kind of concerned about the effect on other sections of the machine if it's true that everything is operating at 140% normal voltage.

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All I ask is a wide screen and a projector to light her by...

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 29, 2015 06:59 AM

Thanks very much for your explanation Andrew, I guess I have to think what to do. It's the only 800ft. and sound projector I still have. Since I am going through my collection to see what to sell and determine print quality (I also don't have an editor/viewer anymore) I am going to use my Eumig 607D for now on my 400ft. reels.

Ha, I also found a few 1200ft. reels, guess I have to find an Elmo 1200 :-)

EDIT: Steve, seems our messages got posted at the same. Maybe you're right and I have some sort of short circuit. Will check it out, thanks.

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 07:01 AM

Me too Steve! That is why I advised Harm not to be using the machine in its current state, if you pardon the pun!

Also be certain to address this problem Harm if you are planning to sell this machine any time in the future. Passing it on in its present condition could be passing on a potential dangerous device if the windings are faulty on the transformer.

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

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Harm Jan Heling
Film Handler

Posts: 33
From: Dutch, living in the Czech Republic
Registered: Jan 2013

posted March 29, 2015 07:30 AM

Could it be a short circuit in the bulb holder, where the pins go? Seems a bit brittle.

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 07:35 AM

This would cause the lamp fuse to blow Harm due to an increase in current, not increase the voltage.

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

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Dominique De Bast
Film God

Posts: 4486
From: Brussels, Belgium
Registered: Jun 2013

posted March 29, 2015 08:01 AM

I know this will not help but as this thread is active again, I checked the pins of my bulbs. There is no difference in their shape between 12v100 watts and 24v250 watts.

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Dominique

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 08:45 AM

The pins are a different diameter and length.Also the pitch between the pins is different. The 12volt 100w A1 231 type are wider spaced than the pins on the 24v 250w type. Though logic would suggest this design difference should surely have been the other way around.

The pins, as logic would suggest, are thicker on the 24v 250w lamps versus the 12v 100w type.

As such different lamp holders exist for the different type lamps, therefore it is important to choose the correct type when the time comes to replace these as they do have to be, after many hours of use.

[ March 29, 2015, 10:15 AM: Message edited by: Andrew Woodcock ]

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

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Dominique De Bast
Film God

Posts: 4486
From: Brussels, Belgium
Registered: Jun 2013

posted March 29, 2015 10:09 AM

After a more acurate look, I could indeed see the différences I didn't see at firs (I've beeb mislead by the picture which let think the différences were more obvious) Doing that, I noticed that I have two bulbs from the same make, one 12v100w and one 15v150w. One has the encouraging mention "projection lamp" written on the box but the other one has a "fibre optic lamp" indication. What's the difference ?

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Dominique

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted March 29, 2015 10:13 AM

Just it's intended use I would guess Dominique. I only ever buy Osram Xenophot lamps in their various different sizes, so I have no idea what manufacturer makes the fibre optic lamps Dominique and therefore do not know if the filament is suitable for any other purpose unfortunately Dominique.

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

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