Problems with durst m605 after lamp exchange

Hi guys,

The 100W lamp of my Durst M605 Color enlarger recently died away and I got a new one from Philipps (also 100W halogen) . When I first tried to make prints again, I noticed, that the projected image was quite a bit darker than it used to be with the original lamp. Also Changing the filter settings and moving the filter "in" didn't result in the desired effect. When I turned the Magenta to 130 for example, it looked like it really was set to 20 or something.

I only get a real effect by turning the filter at the back of the enlarger, the "supplementary filter" in, but I'm not sure if that's the right way to handle this.

I also exchanged the transformator for the enlarger but it didn't change the situation.

Any ideas on this?
Thank you very much!

There's quite a few variations of these 12v 100w dichroic lamps, you need to make sure you got the right type. I think you need an Osram code HLX 64627, Philips 6834 50mm dichroic with GZ6.35 lamp base.

Ian
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Thanks for your reply.
the lamp I got is Philips Type 6834FO 12V 100W GZ6.35 and it looks just like the lamp that I removed from the enlarger and it fits perfectly inside. Do you think I got the wrong one?

That should be the right one. Presumably the lamp holder is back in the correct position, it would be worth cleaning the contacts in the lamp holder, after time they build up oxidation which causes resistance. Make sure the enlargers unplugged first

Ian

you are a genious! I scratched the oxide and dirt off with a thin nail and a little alcohol and now the lamp shines 2 times brighter and I see real magenta if i turn it up to 130

thank you so much

Build up oxidation is always a problem in a low tension high current HLX bulb. Sometimes you have to replace the socket.
Best result for starting is contact spray. It will remove all oxidation.