8mm Forum: B/H meets GS1200

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Posted by Graham Ritchie (Member # 559) on May 03, 2007, 01:55 AM:

Well got into one of my tinkering moods and decided to try fitting a 250watt lamp to the GS 1200. I had an old B/H 16MM the worm gear was gone so I thought if I could use its transformer and the lamp switch, plus a lamp holder from an old Singer 16mm. The idea was to see if I can get more light from the GS and to use the Philips ELC/5H rated for 500hrs its the same lamp as I use in my B/H although I dont think it is as bright as the normal ELC lamp, anyway here are some photos.

Thats it with a modified Singer lamp holder the original GS lamp holder is tied back out the road

Sad eh! not much left of the poor old B/H, I used an old speaker box for the transformer etc note the switch for low and high settings

Getting there.

The new lamp, and the original GS lamp holder, the projector can be easily returned to its original condition if things did not work out.

The power supply in place just need a bit of green paint

The projector back in place, the wiring has got some heat shrink to protect it and I have placed a bit of tape over the lamp switch, the switch must be always on when FWD pressed for lamp cooling, the result of all this crazy-ness is that I have a lamp I can run on "Full" that hopefully will give me longer life than if I was to use the 200watt the same way, the brightness of the new lamp is good on high I would really need a light meter to be more accurate the total cost for the job was eight dollars about three pound well time will tell if its worth it, so far so good.

Graham.

Posted by Simon McConway (Member # 219) on May 03, 2007, 02:17 AM:

Is all that work worth it in terms of light output though? I reckon extra heat may do more damage than good.

Posted by John Clancy (Member # 49) on May 03, 2007, 02:51 AM:

Similarities to the HTI conversion but without quite the light or the additional heat perhaps.

I have a similar lash-up in the GS I use for cine to video transfers. Difference is, it's a 20 watt lamp in that.

Posted by Graham Ritchie (Member # 559) on May 03, 2007, 03:11 AM:

Hi Simon
Good point, I know of collectors using a 250watt lamp in the projector as it stands, my main reservation here is in the GS1200 transformer being able to take the extra current. Derann advertise the use of the ELC 250watt, but I must stress the point it is advertised as "Unofficial GS1200" and only ESC 200watt is "Official GS1200" so my thinking is [Roll Eyes]

that as long as I am not using the projector transformer for the lamp, that on the cooling side things should be OK, in fact I would hazzard a guess that with a Xenon model even with its extra cooling, the heat given of at the gate could still be more than what you would get with a 250watt lamp "more light more heat", I will be keeping an eye on things though.

Graham [Smile]

John
Just read your comments, just a question because the ELC is focusing the light thus heat at the back of the apature plate differently or should I say over a wider area than the 200watt is there anything on the projector that could cause problems regarding the extra heat around the apature plate etc as I guess this would also apply to HTI or Xenon lamps how do you get on?

Posted by Lee Mannering (Member # 728) on May 03, 2007, 04:12 AM:

Graham
I think it’s great to see someone take the leap and delve into some trial and error electronics which was the sort of thing I used to do years ago. The idea of running 250 watt lamp in a 1200 may not be so hot, unlike the extra heat that’s going to be about in the lamp house and could possibly damage the machine. But it is good none the less to look at your pictures and see you are well into experimenting and making use of that old Bell & Howell which is far better that throwing it in the skip.

Around 1982 I converted a Eumig 807D to 250 watt lighting and named it “The Elumig”. Also hacked off the spool arms and extended to take 1200ft reels and even got stereo out of it later on ! This used to create many raised eyebrows at our cine club with its external fan blowing away at the whole machine to try and keep it cool. Eventually it reached critical mass and melt down. Looking back these were my golden cine years when money was much tighter with a young family, and I would try anything to create a cinema presentation with good light and sound. A friend used to loan me his GS1200 to re-record my films for later use on the Elumig which was of great help. I wonder if it was the sight of that Eumig which secured me the job of projectionist at a film festival in later years?

Good on ya for having a go, but do look after the GS1200. I would hate to see it go the same way as the long gone Elumig.

Posted by Trevor Adams (Member # 42) on May 03, 2007, 06:13 AM:

Graham,Derek used to say he used 250w lamps in his GS1200 for years and the tranny held up ok.See you in Wgtn???? [Smile]

regards,Trev

Posted by Graham Ritchie (Member # 559) on May 04, 2007, 12:33 AM:

Lee
Thanks for your comments I watched some Super8 film last night the projector runs well, image was bright and the projector cooling seems fine, with most GS1200 projectors getting close to 30 years old I feel its to risky to run a 250watt lamp using the projector transformer, using an external power source is safer and if the old B/H supply packs up I have lost nothing as the B/H was only good for parts, after reading about your projector I remember an article in Movie Maker and will post some photos etc as a seperate topic that you might find of interest.

Hi Trev
Unfortunately I wont be at the "Wellywood" convention [Frown]

but if the trip to Peter Jacksons "Park Road Post" is anything like the last one it will be very interesting indeed, have a great weekend.

Regards Graham [Smile]

Posted by Kevin Faulkner (Member # 6) on May 04, 2007, 03:37 AM:

Do not stress the Elmo's transformer. They are no longer available so trying to get that extra 2 amps out of it is not worth the risk. Also, like I have said many times before you dont get the full brightness out of the ELC running in the GS because it does not get the full voltage due to the fact that it cant draw the full current from the transformer. Your better off using the EJL as it will at least run at the correct voltage and will give as much light output as the ELC under the same conditions.
Running the ELC from an external transformer like Graham has done is a different kettle of fish.

It would be interesting to compare the std ESC lamp and this conversion but I would expect that the ELC would be less bright as it has the larger filament bunch to cover the 16mm gate and is therefore punching less light through the smaller 8mm aperture.

Heat issues could be a problem and I see that the question has been asked of the extra heat produced by the Xenon version. Elmo have tackled that in a slightly different way on the xenon machine. They did three things...one was to increase the speed of the fan motor, second was to change the shape of the fan blades and the third and more important was to place a dichroic heat glass in the light path between the lamp and the gate. This glass reflects the infrared heat part of the spectrum back towards towards the lamp source which is being cooled by the fan. They also have the filter fitted at a slight angle so that air is being forced onto the filter as well.
This all works very well and certainly my Xenon keeps very cool in use and is certainly no hotter than the std machine. I think Bill Parsons also applied the same filter to Johns HTI conversion but without the extra forced cooling. Johns machine certainly seems to run cool enough and he isnt having to continuously refocus due to expansion of the metal parts.

Grahams experiment should certainly produce more light than using the EJL lamp in the machine but by how much I'm not sure. Shame you cant do some Lux measurements of the various combinations Graham or can you?

One other beneficial side effect of the mods to the xenon version is the fact that the capstan is now running faster while being driven by the faster fan motor. I have noticed on my Xenon that the machine gives less wow when it first starts up because the film has less work to do bringing the capstan up to its final running speed. Its a shame Elmo didnt apply this mod to all GS's but then having said that the xenon does produce much more fan noise.

Kev.

Posted by Lee Mannering (Member # 728) on May 04, 2007, 06:13 AM:

I totally agree with Kevin. I used to use a 250 watt lamp in my other 1200 until I saw the light. (get it). Had a transformer made to measure for a conversion of a 9.5mm Vox sound projector so got deep into Amps etc at this time with a guy who used to do much calculating for a large electronics company re components and it is a sensitive issue with extra heat and a wider focus of light around the 8mm gate area.

Didn’t want to say so much at present but I am in the process of requesting lamp distributors via my trade contacts and I indent to carry out a full test of the 200 watt lamps to see which one is all round best for the GS1200 machine. I will be getting technical help with this as I do not have the test gear here, but I should have results in a few months if the manufacturers are cooperative.

Loving my recent GS1200 purchase so much I am loathed to muck about using the wrong lamp in it and this does seem to be a grey area.

Posted by John Clancy (Member # 49) on May 04, 2007, 12:43 PM:

Kevo's spot on with the information about the HTI converted machine Graham. All I'll add is Bill Parsons did a wonderful job and I've been smiling ever since [Smile]

Posted by Graham Ritchie (Member # 559) on May 06, 2007, 04:21 PM:

I will see if I can borrow a light meter, it would be interesting to get a more accurate measurement, although in the past I have been using EJL 200w I have never been that happy with the light output, it always seemed very dull in comparison with the B/H 16mm sitting next to it, [Frown]

although with 16mm and its 2 bladed shutter etc this is to be expected, using the ESC in the GS1200 I expect would be brighter than the EJL. I remember when the GS1200 first came out a collector at that time was critical of the fact that the ESC was not lasting long and of the high cost of lamp replacement, I think it was around $60 a lot of money back then, for me owning a GS1200 was just dream world stuff, [Roll Eyes]

and many years would pass before I could afford one "now I have three" there is a chap who repairs them in Auckland, who, when I phoned for parts thought owning three GS machines was very funny, ever had the feeling you had the word "sucker" stamped on your forehead, well my thinking is, [Roll Eyes]

that although the GS1200 is a good projector, for the future you still need plenty of back up. I have well and truly veered of the topic of lamps [Eek!]

its always interesting reading everyone views.

Graham. [Smile]

Posted by Graham Ritchie (Member # 559) on May 22, 2007, 02:31 AM:

Well I have been using the GS1200 a lot lately and am very pleased with the results using the 250w lamp on high the projector has been running like a charm, and as cooling goes seems fine, with the extra brightness the colours are brighter, in fact I would venture to say even the focus looks sharper, the cost of the lamp was 40 dollars just under 20 pound and if I only get a few hundred hours out of 500 that the lamp is rated I will happy, "was it worth it"? Yes.

One change I did was to remove the Singer bracket,and re-fitted the original Elmo for more accurate lamp alinment.

here is a photo of the old B/H power supply

one good thing using the original B/H switch is that you can run the lamp on the low setting shortly before switching to high giving the chance for the lamp to warm up

Graham.

Posted by Mark Norton (Member # 165) on May 22, 2007, 01:49 PM:

Congratulations on what seems a sensible modification Graham. Many disco effects lighting run a 250w lamp, some time ago I was considering buying one of these for the parts to do the same to my ST600.

Posted by Tony Milman (Member # 7) on May 22, 2007, 02:43 PM:

Graham,

Why not have a go....thanks for sharing.

Kevin,

As you can't get an original transformer for the 1200, can you buy an external one and fit the wires to the right bits inside the GS? OK clumsy and not as portable but if it kept it going....

Posted by Kevin Faulkner (Member # 6) on May 23, 2007, 09:06 AM:

I don't see any reason why this couldn't be done....yes good idea [Smile]

This is what Graham has done here except his original transformer is still OK.
Its possible that if the original transformer died it could be the primary winding. This would kill the whole machine [Frown]

I dare say that the original could be rewound. There are plenty of companies that can do this in the UK.
I still wouldn't put the 250W lamp in the GS on it's original transformer and anyway it will not give the lux output which Graham's gives running on a transformer capable of the 10 amps the lamp draws.

Kev.

Posted by Patrick Walsh (Member # 637) on May 29, 2007, 01:49 AM:

Hi Graham
Heck that B&H looks like something I used to have!......hang on a second!.....no it couldn't be!.......yes it is!!!!!!!!!!
[Wink]

Pat

Posted by Graham Ritchie (Member # 559) on May 29, 2007, 03:02 AM:

Hello Pat
Sad ending to your old B/H projector [Roll Eyes]

whats left is in a box [Frown]

look forward to seeing your new GS1200 [Cool]

tomorrow.

Graham. [Smile]

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