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Author Topic: Converting Marc 300 projectors. Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 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.?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 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  |  IP: Logged Michael Harlow Expert Film Handler Posts: 170 From: Faversham, Kent, UK Registered: Jul 2002 posted 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 ?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 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  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 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.  |  IP: Logged John Spooner Expert Film Handler Posts: 186 From: South Australia, Australia Registered: Jan 2003 posted 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.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 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.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 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.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-18-2003 03:22 PM                     It's been so many years, I'm afraid I don't recall 100%.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 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.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-18-2003 10:58 PM                     originally the Marc product was GE and the Gemini was Sylvania and it did have better colour temperature  |  IP: Logged Ken Layton Phenomenal Film Handler Posts: 1452 From: Olympia, Wash. USA Registered: Sep 1999 posted 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.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 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.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 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.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 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.  |  IP: Logged

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