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  #21  
Old 8th September 2018, 06:24 AM
chefsteve chefsteve is offline
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Hi
Silly question, but is it possible that the transformer is damaged and not giving out 12v ?
forgive my stupidity if this is not possible.
Steve
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  #22  
Old 8th September 2018, 07:27 AM
Keith Haithwa Keith Haithwa is offline
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Quote:
Originally Posted by Mike O'Pray View Post
As a matter of curiosity, Quendil, can you tell us the name and other relevant details of the bulb that is already there. I am not saying don't buy another bulb as a spare anyway is worthwhile but if what you have in the enlarger fits and is a quartz halogen then I wonder how it comes to be the wrong bulb?

Maybe others can say what might fit the LPL but be the wrong bulb.

Mike
Colour enlargers such as the LPL one in question are designed to be used with a lamp of a certain spectral output/colour temperature if predictable printing results are to be obtained with both colour papers and B&W Multigrade papers as a member here found out to his cost when he couldn't obtain consistent B&W prints until he changed to the lamp shown in my original post.

The lamp I recommended is not sold locally where I live in the UK but there are many other similar fitting 12v 100w 'projector/domestic use' lamps for sale at a fraction the cost of the Osram. I am guessing that the odds are that OP picked up one of these - in which case problems await. There may be other manufacturers of suitable lamps (I haven't found one) but given the EU push towards getting rid of all incandescent-type lamps I have ordered a couple of spares just in case production ceases.

Incidentally, the mixing chambers of these enlargers are formed from polystyrene within a metal outer casing, they do not contain mirrors.
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  #23  
Old 8th September 2018, 07:56 AM
JimW JimW is offline
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Personal experience with a generic bulb in my LPL (badged Jessops) enlarger wasn't good. I gave up and purchased the correct bulb as specified.....
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  #24  
Old 8th September 2018, 09:54 AM
JOReynolds JOReynolds is offline
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Tungsten-halogen lamps at around 100W have a colour temperature of 2950K ...3200K at the specified voltage, depending on their original purpose. This varies significantly with applied voltage, which is why constant-voltage transformers are recommended for colour printing. I have never encountered this recommendation for B&W.
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  #25  
Old 8th September 2018, 07:33 PM
Flakey Flakey is offline
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Hi all.
I also have an LPL C7700
Would it be possible to get hold of a copy of the manual
Thanks Fintan
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  #26  
Old 8th September 2018, 08:30 PM
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MartyNL MartyNL is offline
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Quote:
Originally Posted by Flakey View Post
Hi all.
I also have an LPL C7700
Would it be possible to get hold of a copy of the manual
Thanks Fintan
Hi Fintan

Try this link
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  #27  
Old 8th September 2018, 08:37 PM
John King John King is offline
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In all honesty I would put it down to the bulb not being quite the rated output. There is a lesson to be learned here and that is not to but items from EBay.

I have known people buy other small electrical items from EBay only to have them fail or not live up to what they purported to be.
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  #28  
Old 8th September 2018, 08:49 PM
John King John King is offline
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[QUOTE=Keith Haithwa;121068]There may be other manufacturers of suitable lamps (I haven't found one) but given the EU push towards getting rid of all incandescent-type lamps I have ordered a couple of spares just in case production ceases./QUOTE]

As far as I am aware the discontinuation of incandescent tungsten/halogen bulbs, is for household type bulbs only. Equipment requiring that specialist type of illumination will still be available.

Additionally the overwhelming majority of vehicles 'dipping' headlight bulbs are still halogen type and although it is possible to convert them to use LED types, it is illegal to use them anywhere in the EU unless the vehicle was constructed to use them and given type approval by the respective countries. It is all to do with the focusing of the beam and the angle of 'dip' it can do. Also there has to be some way of cleaning the headlight lens.
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  #29  
Old 9th September 2018, 08:08 AM
Keith Haithwa Keith Haithwa is offline
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Quote:
Originally Posted by JOReynolds View Post
Tungsten-halogen lamps at around 100W have a colour temperature of 2950K ...3200K at the specified voltage, depending on their original purpose. This varies significantly with applied voltage, which is why constant-voltage transformers are recommended for colour printing. I have never encountered this recommendation for B&W.
Sorry, I should have been more specific. With B&W printing I was referring to the use of Multi Grade papers and using Multi Grade filters and/or the enlargers built-in filtration system. I don't have the technical specification for this lamp but Osram list it as having a 'dichroic reflector' - whatever that means. I'm sure a message to Osram would clear up the confusion but for two of us it was the solution to a problem we were having due to the 'wrong' lamps being in the enlargers.

John King: I haven't found this lamp listed as a 'specialist' item John, hence my concern (or is that paranoia).

Late addition: I have just had this in fo sent to me:

'A dichroic coating is essentially a thin layer of non-metallic film, sometimes referred to as interference film, which reflects visible light from the filament forward whilst filtering infrared radiation and allowing it to pass through the back of the lamp. Since IR radiation is a significant source of heat, the net effect of this is to make the beam much cooler'.

Now I appreciate that the term 'cooler' in the above quote refers to actual heat projected forward but the reduction in the amout of infrared radiation projected forward obviously must have an effect on the B&W printing paper as it is sensitive to IR. Perhaps this is the reason for the difference in lamps, just a thought....

Last edited by Keith Haithwa; 9th September 2018 at 08:26 AM.
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  #30  
Old 10th September 2018, 05:17 PM
Quendil Quendil is offline
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Unfortunately the bulb I purchased has no details on it so cannot compare it to another type. I will get an osram one at some point but currently using a Durst 370 so don't need the lpl running yet
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