8mm Forum: 150 watt bulbs, living fast, and dying young

This is topic 150 watt bulbs, living fast, and dying young in forum 8mm Forum at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=006344

Posted by Brian Paul Cook (Member # 1946) on July 09, 2011, 11:24 PM:

I am writing due to my disappointment with GAF 2000s and 3000s, and CHINON 7500s and their wonderful 150 watt bulbs. First, does anyone know if the Chinon projector has a fan in it to cool the high wattage bulb, because the GAF does not, and as a result the bulb lasts a whopping 8-10-12 hours before going dark. The picture quality on my GAF 3000 is remarkable, almost as good as having a 1.0 lens, maybe better in some cases. The extra light makes for a bright, crisp picture with good depth as well. Has anyone found a way to lengthen the life of these bulbs? Or know about the Chinon, which I have been told is the same machine. I appreciate anyone's help on this. I thought about buying one of those little fans and sit it in front of the projectors side slots while showing a film in an attempt to cool it at least some.
On a different subject, I am planning to list a bunch of Super 8mm sound shorts and features in the next week or so. Please take a look at my list. I have tried to keep the prices very fair and will get the films out as soon as payment is made. Thanks again and my appreciation in advance to anyone who can help. Brian Cook

Posted by Bill Phelps (Member # 1431) on July 11, 2011, 04:33 AM:

Brian....I don't have any solutions for you but I feel your pain. I have a GAF 3100 and I really like it. My main projector is a Elmo ST1200 but I have the GAF set up in another room and I use it to do transfer work because of the variable speed option. I have also blown thru some bulbs. I have a few spares. I save this projector for only transfer use now...just last week as I was using it I was saying to myself "I hope it makes it thru this reel!"

The current bulb has been in there a while....your not alone my friend!

Bill [Smile]

Posted by Thomas Dafnides (Member # 1851) on July 11, 2011, 07:58 PM:

Curious, if the GAF does not have a direct bulb cooling fan...doesn't it have an exhaust fan...to expel hot air out?

Posted by Brian Paul Cook (Member # 1946) on July 13, 2011, 07:20 PM:

HI. Thanks Bill and Thomas for your response. Wish someone had some sort of solution to this dilemna but I thought it was wishful thinking. And no, there is no air being drawn through this machine at all. The Chinon 7500 is supposedly the same machine but I have heard rumors of it having an exhaust fan. I'll post it when I know something factual. Thanks again, Brian.

Posted by Thomas Dafnides (Member # 1851) on July 13, 2011, 07:45 PM:

Bozo the clown must of the been the head engineer when they designed the GAF....I have never heard of a movie projector without an internal fan.
But here are a few tips, make sure after projection..that you do not move the projector for at least 30 min. to avoid damaging the hot fragile bulb filament.
I do 95% of my projection in the winter months because the cooler ambient temperatures does wonders for bulb life..it seems the bulb life is extended 2 -3 times over summer projection. Whenever a bulb does go..it is almost invariably in the summertime. This is my experience.

Posted by Pasquale DAlessio (Member # 2052) on July 13, 2011, 08:21 PM:

Brian

Is there any way to install a computer fan inside the unit to circulate the air? They are small and move a lot of air. [Confused]

PatD

Posted by Terry Lagler (Member # 1110) on July 13, 2011, 08:33 PM:

Interesting about the 3000 - I have a 3100S also with a 150w lamp (DNE) but it does have a fan that expells the heat. I find the lamp life on the short side too but I thought that was just the nature of DNE lamps. The 3100S is internally the same as the Chinon 7500 (My GAF has some 7500 parts in/on it!)

Brian is right, the picture quality is excellent and it is a quiet projector too - needs a loop restore feature though.

Cheers
Terry

Posted by Joe Taffis (Member # 4) on July 13, 2011, 08:59 PM:

Brian, I've had several 8mm/super8 projectors since the 1960s. The normal life for these lamps, like the DNE 150w in my CHINON 7500, is 12+ hours. This is and was the normal life expectancy of these and other 8mm projection lamps, and was accepted by projector owners. No disrespect, but if you had been in the hobby as long as some of us older guys, I don't think you would have a problem with this.

Posted by frank arnstein (Member # 330) on July 15, 2011, 08:05 AM:

I have also encountered this annoying problem of a very short life span for Dichroic 150w Halogen lamps fitted to Chinon 7500, 8500 and 9000.

I have seen a brand new 150w lamp crack into 2 pieces after a movie was played & the projector was already turned off.
This was due to uneven cooling of the very hot dichroic lamp reflector. 150w puts out a lot more light than 100w & with that you get a big increase in heat. We have to get rid of that heat or it just builds up and up in the dichroic reflector which acts as a heat bank.

The way to overcome this problem is as follows.

After running a movie through the projector, don't turn it straight off as the lamp will still be soaked with heat & extremely hot.
Run the machine with the lamp turned off for about 3 or 4 minutes & feel the exhaust air temperature with your fingers as it leaves the top of the lamphouse.
You will find that it starts off by pumping out very hot air. Gradually, as the heat is removed from the dichroic reflector, the exhaust air will feel cooler and cooler. Once its cool you can safely turn off the projector.

The air flow on these is from back to front and then up and out.
The fan is located inside the rear compartment, driven off the projector motor. It draws its air in from the vents on the back cover then blows it through a large hole behind the lamp. The cooling air then goes over the lamp to soak up heat before going up and out through the lamphouse cover exhaust vents. Thats where to feel the air temperature with your hand.
Don't run the projector without the lamphouse cover on because it forms part of the airflow ducting and removal could interfere with air flow around the lamp.

So for those Chinon & Gaf owners that don't know what to try next, there is a way to improve your lamps life. [Smile]

Posted by Osi Osgood (Member # 424) on July 15, 2011, 10:29 AM:

This has always been my one problem with my Chinon 9500. Great optical sound output, (and the stereo is great on it as well) ...

but those danged bulbs are expensive, and only last approximately 12 to 15 hours! I'd love to find a long lasting bulb for that projector!

Posted by Thomas Dafnides (Member # 1851) on July 16, 2011, 07:45 PM:

Osi, I have the 9500mv which uses the EFP lamp ( 100 watt), my bulbs last well over 50 hours , maybe 100+. And I do not see why not, with a pre-heated filament warm-up, direct bulb cooling fan and the incredible venting system. After 25 min, the lamphouse only feels warm to the touch.

UBB.classic^TM 6.3.1.2