8mm Forum: Extending the life of the projector bulb.

This is topic Extending the life of the projector bulb. in forum General Yak at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=8;t=004272

Posted by Ronald Green (Member # 5655) on January 29, 2017, 08:26 PM:

This may sound silly and I don't mean it too; however, I really didn't get 30 hours of life on my projector bulb like it says.
Don't put projector away until 1/2 hour after the film is shown.
I do play the projector everyday, especially comedies to get my day off to a good start after watching the news.

Appreciate any suggestions. Thanks.

Posted by Dominique De Bast (Member # 3798) on January 29, 2017, 08:41 PM:

If you can set the voltage of your projector on a higher value, you will extend the life of your bulb (but you will also have a less brighter picture). If your projector is set on 110 volts, set it on 117. If it is already set on 117 colts and you can set it on 127, try to do so. I understand that the stability of the voltage is more difficult to get with a "110 volts" system than with a "220 volts" one. in other words, you may in theory get someting from 100 to 120 volts in the "110 volts" network while in the "220 volts" operator will provide you a voltage close to 220 (again, it is theory, in Europe, the voltage is no longer 220 volts anyway but 230 volts and in soe countries even 240 I think).

Posted by Steve Klare (Member # 12) on January 29, 2017, 09:37 PM:

I think the key is using projectors that use good, cheap lamps and finding a place that sells them even cheaper!

The ones I use run with EFP and EFR and I buy 'em for less than 10 bucks a pop! Every other year or so I buy a bunch of them and I don't worry about it a while. (I just got three of each last week.)

I remember the half hour cooldown ritual from my Dad's days showing slides! If was like when Mom made a cake: "NOBODY MOOOOOVE!!"

-seriously: do cakes really "fall" because some kid a block away is using a pogo stick?

Posted by Maurice Leakey (Member # 916) on January 30, 2017, 02:31 AM:

At the end of your show let the motor's fan assist with the cooling of the switched off lamp.

Posted by Brian Fretwell (Member # 4302) on January 30, 2017, 03:01 AM:

A note about voltage to add to advice given above.

Not projector lamps, but other halogen reflectors. I was told by an assistant at an electrical trade outlet that running a lamp at 90% of it's rated voltage doubles it's life. Of course some projectors have a high and low brightness setting so it must make a noticeable difference.

Posted by Andrew Woodcock (Member # 3260) on January 30, 2017, 03:58 AM:

It's true but personally, I can't stand the look of any lamp on less than 100% of its rated voltage.

The underun lamps lack any vibrancy on screen imo unless projecting a tiny tiny image.

Posted by Gary Crawford (Member # 67) on January 30, 2017, 07:51 AM:

Just like miles on your car, you'd be surprised how quick hours on a bulb add up. I'm not sure about this next statement, but someone once told me that bulb life in some cases is tested by turning it on and letting it go until it fails. This, as you know, would give a much longer life, in most cases, than turning the bulb on and off every 10 minute reel, etc.

That surge when turning on can shorten bulb life. That's why some machines like the Elmo's and some Eumigs, when you turn them on, send low level current to the bulb, making it just glow. Supposedly that extends the life of the bulb ..and I'm pretty sure it does. Even so, most bulbs burn out when you turn them on, and far fewer bulbs go dark in the middle of a film.

I would bet also that the cooling system in various projectors vary a lot. Poor fan circulation has to be factored in . And who knows under what conditions the bulb manufacturers tested and rated their bulbs.

I'm sure the engineers on the forum, like Steve Klare, know tons more about this than I do. I'm just speaking from over 50 years of collecting films and messing with all kinds of machines.

Posted by Steve Klare (Member # 12) on January 30, 2017, 08:11 AM:

Mr. Crawford, you flatter me!

-unfortunately in this case without cause: actually a lot of what I know about electric lightbulbs is because I collect films, and a lot of that I learned here!

-but: I do remember in an old Guinness Book there was this World Record holding electric light that had been burning at a fire station somewhere for over 50 years at that time.

-it had been burning continuously.

What usually kills a lightbulb is the filament gets so hot that tungsten atoms evaporate off the surface and condense on the much cooler envelope. Every time you turn it on, it undergoes this mechanical shock. When there is not enough metal left to withstand it anymore you are routing around in the drawer, hoping that wasn't your last one.

This is why the preheat circuits help, it divides the big shock into two smaller ones.

Posted by Chip Gelmini (Member # 44) on January 30, 2017, 08:51 AM:

I could write a very big post about this, but do not have the time.

One reason why I like running super 8 so much is because I worked in cinema running 35mm for 32 years. Here on the job, there were procedures in the booth per company policy that were done. These tasks kept the equipment in pristine condition if the guys did the work and the company followed through with replacing the parts as required.

One procedure from work which I adapted to super 8 was lamphouse maintenance. Whereas, we kept records of bulb installations, opened up and cleaned the lamphouse once per month, recorded on index cards total of hours burned, and so on. As bulbs darkened we replaced them. During inspection they were rotated so the anode and cathode (the points between the flame) burned evenly. This reduced the flicker.

At home running the GS 1200 and the standard EFR bulb I generally do the same thing. Modified given the smaller format.

Things you can do regardless of your setup:

1. Maximize your reels. Fill them safely to the allowed capacity.

2. Run with changeovers to keep the show going. Less breaks means less lamp on and off.

3. At the end of a given evening, record on a calendar or a spreadsheet with gridlines on a clipboard that you ran a show.

4. When the calendar or spread sheet has one half the total bulb life, consider an early inspection.

5. Upon inspection:

a. if the bulb reflector is pitted or fogged
b. if the filiament glass is dark
c. replace the bulb

d. if running with changeover replace both bulbs

e. when ordering bulbs get the same kind brand name
f. running with changeovers keeps the switch over at equal brightness when the brands are identical

Now all of you might find this ridiculous to do. But let me tell you in 25 years of running super 8 since I adapted these procedures I have NEVER EVER EVER lost a bulb during the reel or show.

If a bulb is rated at 50 hours and I discard it at 35, I would rather eat the cost and gain a brighter non-problematic image. Especially when the bulbs are under $20.00 a piece.

And by the way, I change bulbs about once every 2 years on average.

If it works at the multiplex, it does work at home.

I could go on a little more, but you get the point. Ask questions if you have them.

Seriously guys. This works.

Chip Gelmini

Posted by Mathew James (Member # 4581) on January 30, 2017, 09:02 AM:

Real valuable advice here!!
I am no expert by any means, but so far my bulbs have run pretty long and i do run film quite a bit... Chips tips(hey, that has a good ring to it..."Chip's Tips") are very good indeed to try! I have switched to osram bulbs on all mine.
One thing is that i always run the fan to cool the bulb during and after play.
What i mean is, on my elmoST1200HD for example, you can either turn the machine off completely whilst changing reels or at the end or projection, or you can keep it in fan-on mode(neutral).

I am not sure if this works to prolong the bulb, but i cant see how it hurts to keep things cool. I run my fan after projection until i put my hand above and no more air is blowing warm.

Posted by Brian Fretwell (Member # 4302) on January 30, 2017, 09:58 AM:

With respect to cooling with halogen bulbs if the envelope is cooled too much and the quartz/glass in it also cools you can get the tungsten condensing on the envelope rather than back on the filament. I was told this was "Operating below the halogen cycle temperature." It mainly affected stage lighting halogens on dimmers but could be relevant here.

Posted by David Roberts (Member # 197) on January 30, 2017, 10:37 AM:

I always run on the "low" setting of the lamp and don't mind at all the slightly reduced brightness for home shows.
I cant remember the last time I had a lamp blow,they just seem to last for ever!

UBB.classic^TM 6.3.1.2