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Topic: Elmo GS1200 Light fault...HELP Please
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Andrew Woodcock
Film God
Posts: 7477
From: Manchester Uk
Registered: Aug 2012
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posted February 08, 2017 04:37 PM
Though it is very much against first principles, some things at times DO have to be tested "live" if you are working to a budget and don't want to waste time as well as money.
If you feel confident John, i was going to suggest you measure the voltage at the point the lamp holder leads are soldered back to the switch / transformer.
The reason being, from the symptoms you are describing, it isn't typically what you would expect to see if the lampholder was faulty.
Typically as these are coming to the end of their serviceable life span, you see the lamp going on and off in quick succession.
You also commonly see arcing to the lamp pins in evidence, or blue discolouration to the lamp pins.
Often the lamp pins will stick in the holder where they have virtually welded themselves to the holder contacts, in a similar manner that relays and contactors do the same after prolonged use.
Have you seen any of these symptoms to suggest that it is definitely your lampholder that is at fault here?
Incidentally, any lamp holder works well to begin with, I only endorse B&W Lamp Holders as i have found over the years that these last the longest with the least hassle.
By all means, if you are certain it is the lampholder, then take Paul's advice, but if you do insist on a B&W lampholder if you are perhaps a heavy user of your machine, then the type you would need is this one pictured here.
Model number- 881 rated at 10 amps.
This gives you a little headroom on the maximum current capacity of this which adds to its longevity.
Ensure the cables are well insulated all the way back to their soldered joints also.
Here is one I fitted a few years back now,..
I find they work better and last longer with the holder mounted in a horizontal plane rather than vertical as is often seen.
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"C'mon Baggy..Get with the beat"
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John Hunter
Junior
Posts: 30
From: Gretna, Scotland
Registered: Jun 2015
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posted February 09, 2017 02:22 PM
Andrew. I traced the wires from the lamp socket back to the transformer as best I could, and found nothing to worry about. I then got my meter out, and checked the voltage at the lamp socket and found them to be only a volt or so down from what they should be. As a check I took a reading at the trans, and found them the same!! The lamp would not stop working!! I pulled the wires behind the socket, moved them at the trans, but the lamp did not flicker. Now I wonder if I have been mislead, and the fault is elsewhere. As in my first post to you, I said the picture was not as bright on a 4 foot screen as I thought it should. Taking the lamp out, putting it back, then the lamp not working at all, may have hit a point on the socket that was about to give trouble in near future. But, the 4 foot screen I used, was bought on e-bay some years ago, and this was the first time I used it. In the past I used an 8 foot screen permantly mounted in the bay window-good on wide screen films-but my wife wanted a different curtain rail and curtains, so it had to come down!! The circuit diagram showed no tappings on the transformer input, and is not provided, but the Elmo label on the rear of the machine, states its a 240v projector. I metered the mains, and found it to be 230. I have always assumed it to be 240. It may be the reason for the drop of a volt or so at the lamp. I am always careful with high voltages. I am a radio ham, and some years ago while working on the back of my transmitter which was in a 6 foot cabinet, and I was working on the power supply in the bottom, I touched a point at 1500v and I was flung against the wall. I was lucky my other hand was not touching the earth, or I would not be having trouble with my gs1200!! So this trouble could be caused by a ebay scree.
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j.hunter
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Paul Adsett
Film God
Posts: 5003
From: USA
Registered: Jun 2003
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posted February 09, 2017 08:01 PM
You are wasting your time (and ours ![[Smile]](smile.gif) ) until you have replaced the lamp socket as Graham and I have suggested. The voltage on the lamp leads tells you that the transformer is supplying the correct voltage to the lamp, BUT the contacts are not capable of carrying the 8 amps current. Please replace the lamp socket and you will find that it fixes the problem and your screen illumination is better than ever.
Also, instead of trying to solder the lamp wires, I would recommend that you cut the lamp wires in the lamp housing, close to the old socket, and use a screw type terminal connector to connect up the wires from the new lamp holder. That way, any future replacement connector (and you will need one every few years) can be hooked up in a couple of minutes.
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The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj
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UBBFriend: Email this page to someone!
![[Frown]](frown.gif)
The contact between the lamp pins and the socket are inadequate and always have been for the current the lamp draws and over time they give up.
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