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Posted by Ilias Sifakis (Member # 2417) on February 07, 2011, 04:11 PM:
 
Hello to all,

Yesterday I found a 400' reel and turned on my Eumig to screen it.
The lamp light up and in 5 seconds it got burned.

A bit of history: I bought the projector like 15-20 days ago from a local collector. I brought it home, watched around 20 mins of films and then the lamp burned. I bought a new lamp, used it for around 3, maybe 4 hours tops and today it burned....

Facts, the lamp that was in the projector when I bought it and the lamp I purchased when the first burned were 75 w 12 v. However, the projector states on the back side and the inside that it can take a 100w 12v lamp. Is there any possibility the lamps are easily burned because of the lower wattage?

Also, is there any chance that the projector has any kind of problem that is not easily noticed? like a short-circuit or something?

I'm not moving the projector when the lamp is on, neither before the lamp is turned on, nor after its turned off....

Any help would be greatly appreciated....

thanks
ilias
 
Posted by John Davis (Member # 1184) on February 07, 2011, 04:51 PM:
 
Not knowing if the projector was used in Greece before you got it, have you checked that it is set to the correct voltage?
 
Posted by Ilias Sifakis (Member # 2417) on February 07, 2011, 05:11 PM:
 
thanks for the reply John.

The supply voltage is correctly set at 220 volts, I checked that before the first time I plugged it in the socket...

any other thoughts anyone?
 
Posted by frank arnstein (Member # 330) on February 07, 2011, 05:41 PM:
 
Hi Ilias

Put in a 100w lamp & you will find no more problems.
A 75w will soon blow. It needs 100w to work Ok.

dogtor frankarnstein [Wink]
 
Posted by Ilias Sifakis (Member # 2417) on February 08, 2011, 12:43 AM:
 
thanks a lot for your reply Frank.

I really do hope that you are correct. I'll go find a 100w lamp today.
I hope this will help, cause i'm really sad about the whole thing.
I have been so excited about my new hobbie and projector, that I cannot deal with a broken projector :S

I'll buy a lamp and will let you all know what happened.

In the meantime, if anyone has any more ideas about possible faults in the projector that might be easy to check (i'm kind of keen with electronics and tools) i'd be more than happy to read your thoughts [Big Grin]
 
Posted by Lee Mannering (Member # 728) on February 08, 2011, 01:45 AM:
 
Hi
Before you try the new 100 watt lamp set the mains voltage to 240 volts for safety. It will very slightly lower that lamp supply; the lamp will last much longer particularly if you have a fault brewing. See how this goes and after testing time you can gradually increase the voltage on the Eumig transformer back to 220 if you choose to.
Happy days!
 
Posted by Ilias Sifakis (Member # 2417) on February 08, 2011, 01:51 AM:
 
Lee is it safe to set the projector to accept more voltage?

If I understand correctly, you're saying that the problem might actually be the flunctuations of the electricity supply?
And if I set the voltage input to 240v I will facilitate the extra voltage that might go through the projector in case of a flunctuation ?
 
Posted by Lee Mannering (Member # 728) on February 08, 2011, 02:38 AM:
 
Hi. As your mains voltage is 220v setting the projector at 240v will not harm it as you are basically telling the transformer to expect more voltage when you are in fact only feeding it 220 volts. If ever I have had fuse blowing problems for instance on any electrical unit and there is variable voltage option on the transformer its always a good idea to set the transformer to a higher setting to protect the electrics for a test period.

Whatever YOU do never set low voltage on the transformer than 220v as this will certainly blow fuses and worse.

Our mains voltage here is 240 volts, but I slightly over run one of my Eumig 824 machines at 230v setting to squeeze a little more light out of it and it has been on the 230v setting for something like 30 years. This one I also converted to a 2 blade shutter and it projects a nice bright picture as result which is handy for larger halls.
 
Posted by Martin Jones (Member # 1163) on February 08, 2011, 03:16 AM:
 
Frank,
Can you explain your thinking behind the statement that...
"A 75w will soon blow. It needs 100w to work Ok".

In all my years as an Electrical Engineer (about 55) I have always understood that the only effect of using a 75w instead of a 100 watt is that you get less light. As Lee says, the ONLY external criterion that affects lamp life is the VOLTAGE applied to it; if the Voltage is too high the lamp will dissipate more power (watts) than it is designed for, will overheat and burn out quicker.
Regards,
Martin
 
Posted by Ilias Sifakis (Member # 2417) on February 08, 2011, 03:20 AM:
 
Martin & Lee thanks a lot for your input.

I'll go buy a lamp today, hopefully a 100w (is also cheaper than 75w)...and will also increase the voltage to 240.

So, from all you're all saying, I reckon that probably there's nothing wrong with the projector itself right?
 
Posted by Antonis Galanakis (Member # 1455) on February 08, 2011, 03:59 AM:
 
Ilia
I set all my projectors to 240 V. It is safer to use. You protect the motors and the lamps by doing that. Pay attention to the fact that the voltage in Greece for some years now is 230 V. The voltage sometimes, especially at night, is not so steady and might raise up to 250 V easily.
After that if the problem still exists, just talk to your seller. He is a very honest person and I am sure that he will find a solution.
CU
Antonis
 
Posted by frank arnstein (Member # 330) on February 08, 2011, 03:19 PM:
 
Hi Martin
I have read your informative reply to my post & digested your message re Lamp volts & Lamp watts.

Thanks for pointing out that the voltage to the lamp is the main consideration & a lower wattage lamp only results in less light. Not the cause of a lamp to blow.

This was an important principle for me to learn.
I now realise that you are correct & so welcome this input of yours to clear up a misconception in my mind.

The Specs plate on the back states the recommended lamp to use in your projector so when in doubt, it is best to refer to it. If it says max. 100w, then use 100w for best performance.

dogtor

P.S. Martin,..

Can You tell us what the effect would be, putting a 75w lamp into a Eumig projector that is designed to run a 100w Lamp, like an 810. Would it blow the lamp?
Conversely, what if you put a 100w Lamp into a machine designed for 75w max? Like an 807. Would it hurt the machine?

How would both lamps perform in terms of brightness, & compared to normal brightness?
Would there be any harm done to either lamps or projectors?

Your advice would be appreciated & 55 years in Electronics is a lot of experience to draw on & is much respected.

thanks....
dogtor [Embarrassed]

[ February 08, 2011, 06:09 PM: Message edited by: frank arnstein ]
 
Posted by Ilias Sifakis (Member # 2417) on February 08, 2011, 03:35 PM:
 
thanks for all the replies people [Big Grin]

I bought a 100w lamp today, also changed the voltage input to 240v.

I just screened a 400' reel. All seemed ok, let's now see if it will blow after a few days like the previous 2.
 


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