Film-Tech Forum ARCHIVE: Converting Marc 300 projectors.

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Posted by Stephen Furley (Member # 1277) on 02-16-2003, 02:29 PM:

I have a pair of Bell & Howell 666 16mm projectors, which use the GE marc 300 lamp. These lamps are expennsive to operate, due to the very short life, and are becomming difficult to obtain.

A couple of years ago someone suggested a Sylvania metal halide lamp as a replacement, I can't remember the number, but it would have been too long to fit in the lamphouse; it might be able to replace a marc 350, which is a different shape to the 300.

There are now many small LCD data/video projectors which use metal halide lamps similar in size and shape to a marc 300, and with a life of about 2000 hours, for a cost not much greater than that for a marc 300.

Does anyone have any thoughts on the possibility of converting projectors to use such a lamp? What modifications would be necessary to the power supply, etc.?

Posted by Gordon McLeod (Member # 33) on 02-16-2003, 03:12 PM:

The powersupply will have different characterisitcs as will the optics.
The only conversion I have seen was to a HTI 450 Osram done to some followspots that had use the Marc lamps

Posted by Michael Harlow (Member # 1353) on 02-16-2003, 04:12 PM:

to run a metal / tin halide lamp you would need a ballast / ignitor unit and also decent fan cooling in the lamp house. i have used philips MSD200 lamps in conversions as well as MSR2500 lamps. don't forget these are AC lamps though, would that cause a problem ?

Posted by Gordon McLeod (Member # 33) on 02-16-2003, 05:13 PM:

The beat flicker between the lamp and the shutter is a problem but the more expensive ballasts (called flicker free for this reason) are square wave output or very high frequency pulse modulated

Posted by Steve Kraus (Member # 476) on 02-16-2003, 06:55 PM:

Gordon is referring to a hypothetical halide replacement; the actual Marc lamp runs on DC.

GE made an updated direct replacement for the Marc-300 called a Gemini 300. It's rated at 75 hrs. Low by xenon standards but high compared to high wattage (pre halogen) incandescant.

Sylvania's version of the Marc was called Colorarc. That's a Colorarc with the black leads, Marc with the white.

I'm not sure what the failure mode actually is. I've fired up a supposedly spent Marc or Colorarc using my baby Christie xenon lamphouse.

Posted by John Spooner (Member # 1565) on 02-17-2003, 09:36 AM:

Stephen. I have a B&H 666 with a marc300 lamp, it sits on top of a power supply unit, presume yours is the same. I also have a later B&H projector model 1568 with the newer Gemini lamp and inbuilt power supply.
I tried placing a Gemini lamp in the 1568 as they physically are interchangeable, but upon ignition the 666 power supply damaged the Gemini lamp and it failed.
You may find the results above of some interestin your situation.
John Spooner. South Australia.

Posted by Brad Miller (Member # 2) on 02-17-2003, 09:50 AM:

John, I think you just had a faulty bulb. I've used the Gemini replacement with B&H Marc 300 power supplies many times and never had a problem. The GE power supply is better though, as it has a dimming feature so you don't have to wait the full 2 minutes for the lamp to reach full intensity.

Stephen, if you are unsuccessful changing out the kind of lamp, go to www.bulbdirect.com and click on "search" and enter "marc" and these bulbs will turn up. This place generally has good pricing. Unfortunately the webmaster doesn't know how to code properly, so you'll have to use Internet Explorer. [thumbsdown]

Posted by Stephen Furley (Member # 1277) on 02-18-2003, 11:32 AM:

Brad wrote:

quote:

Stephen, if you are unsuccessful changing out the kind of lamp, go to www.bulbdirect.com and click on "search" and enter "marc" and these bulbs will turn up. This place generally has good pricing. Unfortunately the webmaster doesn't know how to code properly, so you'll have to use Internet Explorer.

Brad, I've seen some GE lamps marked 'Gemini', they were similar to the normal Marc 300/16, but they were smaller, not much larger than the EJL/ELC type halogen lamps. Is there a full size 'Gemini' as well?

The 666s are not the best of machines, but they are bright, brighter than a 300W portable xenon, and, they are small and light, which is important for me, as I don't have a car. I can take one projector plus its power supply to a venue by bus, if I need both machines then I have to make two trips. They are usable, if not bright, on screens up to about five or six metres, enough for the sort of places I deal with, various halls, and cinemas which only have 35mm, and need 16mm for the odd special event.

The lamps are very expensive over here, but someone bought about a dozen from the USA at a much lower price a few years ago, and I bought four from him. Two of those went in last year, and have just a few hours on them, and I have the other two as spares, and I only use them for three or four shows a year, but I will either need to find some more Marc 300s, or some alternative one day.

Posted by Brad Miller (Member # 2) on 02-18-2003, 03:22 PM:

It's been so many years, I'm afraid I don't recall 100%.

Posted by Steve Kraus (Member # 476) on 02-18-2003, 10:32 PM:

The old Gemini literature says it's "Directly interchangeable in present Marc-300/16A lamp systems." That of course begs the question as to why they would still make the Marc lamp. But one vendor lists the Marc 300/16 as "delisted" so perhaps the regular 300 is superceded. There is also a Marc 350 16/T. The power supply required for the Gemini is the same one as used for the Marc 300 and 350's.

There is also a Marc 300/35K which is just an arc tube without the dichroic reflector.

Posted by Gordon McLeod (Member # 33) on 02-18-2003, 10:58 PM:

originally the Marc product was GE and the Gemini was Sylvania and it did have better colour temperature

Posted by Ken Layton (Member # 133) on 02-19-2003, 03:27 PM:

Quick specs on the Marc lamps:

EZG Gemini-300, 35 volts, 8.5 amps, 2-1/4" double D dichroic reflector, 75 hours. Replaces Marc-300/16A

EZM Marc-300/16, 37.5 volts, 8 amps, 3" double D dichroic reflector, 25 hours.

EZS Marc-300/35K, 37.5 volts, 8 amps, bare arc lamp (no reflector), 25 hours.

EZT Marc-350/16T, 45 volts, 7.7 amps, 3" round reflector, 50 hours.

MARC and GEMINI are General Electric trademarks. Colorarc is a Sylvania trademark.

Typical ignition voltage is 4,000 to 5,000 volts which is much lower than what's used to ignite xenon lamps.

Posted by Stephen Furley (Member # 1277) on 02-20-2003, 10:34 AM:

Ken,

This is getting confusing. It lists the Gemini as being a replacment for the Marc 300/16, yet shows the size as being smaller, as with the Gemini lamp which I have seen, so I don't see how it can replace the 300/16, unless they make some sort of adapter for it, which I have never heard of.

Where did you get this info from, was it direct from GE? If so, I think I may try to contact them, and ask for clarification.

Posted by Scott Norwood (Member # 30) on 02-20-2003, 11:28 AM:

The "Gemini 300" is actually the same thing as a "MARC 300/16A", which itself is smaller than a regular "MARC 300." I believe that the power supply is slightly beefier for the 300/16A (aka Gemini 300) as well.

The B&H 566 projectors use the regular MARC 300 and the Kodak Pageants (at least the one that I've worked with) use the Gemini. Not sure about the B&H 666 (with a model number like that, it must be an auto-shredder!).

Did B&H ever make a manual-thread or slotload MARC-300 model? I wouldn't mind having a pair of MARC-300 projectors, but I cannot stand their autoload machines and I won't let my prints anywhere near them.

Posted by Steve Kraus (Member # 476) on 02-20-2003, 11:48 AM:

The B&H autoload is a much more complex mechanism than, say, an Eiki but don't all those bits and pieces withdraw after threading is completed and the snubber tugged on? If all that's left is the standard mechanism then the only thing put at risk is the leader so I guess one could add extra if using an autoload. Obviously I think we all prefer a nice manual thread over either slot or autoload.

The 1568 was the Gemini machine. Eiki had a "Double Duty" conversion where you could use a Marc or Gemini with an external supply or go back to the halogen bulb.

Posted by Aaron Sisemore (Member # 145) on 02-20-2003, 12:43 PM:

quote:
Did B&H ever make a manual-thread or slotload MARC-300 model?

Yes they did. I have a manual-thread B&H 566-series MARC300 machine at home.

-Aaron

Posted by Ken Layton (Member # 133) on 02-20-2003, 05:20 PM:

There is some confusion to clear up. The Marc-300/16 is a different bulb than the Marc-300/16A. The 16A has a 2-1/4" reflector and was replaced in the early 1980's by the Gemini 300. The Gemini 300 was merely an improved (longer life) version of the 16A. A Marc 300 power suplly will operate the Gemini 300, Marc-300/16A, and Marc-300/16. The Marc-350 bulb can only operate with power supplies that specifically state that it will. General Electric and later it's successor North American Power Supplies (N.A.P.S.) built a switching regulator power supply with current sensing built in that would adjust itself to ANY version of the Marc lamps (including Marc-350). This is the power supply that Brad mentioned that also has dimming (standby) feature.

Bell & Howell had these models that used the Marc lamps:

560A Manual threading, tube amplifier (Marc-300/16 lamp)
566A Automatic threading, tube amplifier (Marc-300/16 lamp)
566T Automatic Threading, transistor amplifier (Marc-300/16 lamp)
566EX export version of 566A
566EXT export version of 566T
567 Automatic threading, transistor amp (Marc-350/16T)
1568A Automatic threading, electronic pushbutton control (Gemini-300 lamp)
1568-B Automatic Threading, electronic pushbutton controls, multi-media computer connector, shaft encoder (Gemini-300 lamp)

All above model included "Changeover" for dual machine setups.

There are some versions of the Marc power supply designed to operate on 400 hz power used on airplanes.

[ 02-21-2003, 08:25 AM: Message edited by: Ken Layton ]

Posted by Stephen Furley (Member # 1277) on 02-20-2003, 06:30 PM:

Scott wrote:

quote:
The B&H 566 projectors use the regular MARC 300 and the Kodak Pageants (at least the one that I've worked with) use the Gemini. Not sure about the B&H 666 (with a model number like that, it must be an auto-shredder!).

Did B&H ever make a manual-thread or slotload MARC-300 model? I wouldn't mind having a pair of MARC-300 projectors, but I cannot stand their autoload machines and I won't let my prints anywhere near them.

Most british Bell and Howell 16mm machines had model numbers starting with '6'

I can't remember any of the silent ones, but the earlyest sound one I have used was the 601, this was built into a blimp case, with the small drop down door in front of the lens, and the spool arms, which were stored inside, fitted onto the case, where they were held in place by knurled head screws. The 621 was similar, but the arms just slotted into sockets in the case. These machines ran on 110V, via an external transformer. There was a lightweight version, the 626, which had a smaller loudspeaker, still in a separate case, and ran on 240V, eliminating the transformer. At least some of these machines could be fitted with plug in magnetic heads, for full or quarter width stripe. These heads were above the drum, but by making an oversize bottom loop it is just possible to thread a standard 28 frame advance magnetic print in sync. The 609 was the floor standing carbon arc version, the successor to the pre-war Filmoarc. I have a pair of these, one not quite complete, but I think I know where I can get the missing parts.

The 621 and 626 were replaced by the 631/636, which were similar, but were optical only, I think the amplifiers were also slightly different. The 631 is one of my favourites, it was introduced in the year I was born, and must have looked very modern then.

The 640 was the Mag record version, I also have one of these. These models all had the exciter lamp fed with high frequency a.c., from an oscillator.

The last of these old-type machines had a four-digit model number, it took a 240V lamp, had a partly transistorised amp, small speaker stored inside the case, and sideways opening door in front of the lens. All of these machines took the 750W A1/59 lamp as standard, but could also take the 1000W A1/91, but this was not recommended when running silent or black and white film.

Around the early '60s these machines were replaced by the totally different 'new' machines, as I still think of them, with the large lens barrel. there were many different models, the 642, or was it 641, was optical only, with simple volume and tone controls, the next model up had separate mic and film volume, and treble and bass controls; four knobs, rather than two. Then there were mag playback only and mag record/playback models. Some of these also came in autothread versions. These machines had valved (tube) amps, and took four pin valve base lamps, the A1/206 for 750W, and A1/207 for 1000W. These machines had mains voltage (240V) motors and amps, and normally took 240 V lamps, but it was possible to buy a large external transformer, similar to that supplied with the 631 etc., supply 110V to the lamp, and 240V to everything else, via separate pins on the four-pin Jones plug. There was also a smaller step-up transformer to supply 240V to the motor and amp from a 110V supply, while a 110V lamp was fed directly. This gets complicated, doesn't it?

The next models were the very similar TQ1 range, with transistorised amps, and 24V 250W halogen lamps, which were again a Bell and Howell special, and are now difficult to obtain, but it is possible to buy a conversion kit, not made by B+H, to replace the lamp and separate dichloric reflector with the standard ELC lamp. The 666A to give it its correct number was basically a Marc version of a manual threading, optical and mag playback TQ1, but I think the amplifier is more powerful.

The TQ2 and TQ3 machines were smaller and squarer, but I don't know the model numbers of any of these.

Did bell and Howell ever make a xenon machine, I've never seen one?

I have never seen an auto thread Marc machine.

At the last count, I think I had about twenty 16mm machines, six 8mm, two 9.5mm, one of which also takes 16mm, and two 35mm, different machines, not a pair. I live as a lodger in a small room, so I can't keep any of this stuff at home, it is all stored in various places, or loaned out to people.

It's half past midnight, I went to a late show at the cinema this evening, and haven't been in long, I think it's time I went to bed.

Posted by Aaron Sisemore (Member # 145) on 02-21-2003, 12:42 AM:

quote:
Bell & Howell had these models that used the Marc lamps:

560A Manual threading, tube amplifier (Marc-300/16 lamp)
566A Automatic threading, tube amplifier (Marc-300/16 lamp)

Thanks! I now know I have both a 560A (the machine I mentioned to Scott) and 566A (the 566 has the autoload mech jammed in the load position and I cannot free it).

I only have one power supply however. Anyone got one cheap? [Big Grin]

-Aaron

Posted by Philippe Laude (Member # 79) on 02-21-2003, 02:07 AM:

Aaron,
I have new spare power supplies for Bauer Marc 300.
E-mail me if intersted.

Philippe