Lamp for Durst M605 - 100w or 75w???

[gamincurieux]

Hi again!

Lately I have been having a problem with the 100w lamp on my M605 failing on me (100w being what the manual says to use). Not blowing, rather just failing, not coming on. This is quite intermittent, mostly it comes on, but sometimes it doesn't.

During my last session it would not come back on. I had to restrain myself from belting the head too hard! Not wanting to simply put another 100w lamp in (because I knew it was not blown, it had to be something else), I noticed I had a spare 75w lamp left over from when I sold my Leitz V35, so I put it in. It seems to solve the problem, seems to work fine.

75w lamp is the Philips 12v 75w EFN 6853 A1/230
100w lamp was the Osram Xenophot 12v 100w EFP HLX 64627

Has anyone experienced this or something similar? Is there something I should be aware of in using a 75w lamp..... like, umm, DON'T USE IT...? Is using a 75w lamp why I now really notice light fall-off in the corners? Probably was just as much before, only the light was stronger. Any thoughts will be much appreciated.

Thanks as always, Paul

 

[gamincurieux]

I might add, if it makes any diff - enlarger is running through a new RH Designs Analyser Pro.

 

[gamincurieux]

Don't know what else to add...

 

[Bob-D659]

Well the only difference in the specs is the wattage and the light output, so there is no reason not to use the 75 watt bulb.

Now for the bulb to stop coming on:

Hi temp cutout in the head?

Socket or bulb going open circuit due to overheating. Is the bulb position in the head "base up"? Most of these bulbs are supposed to be mounted between base down to horizontal. The Durst CLS 450 head I have mounts the bulb base up, a good way to overheat the bulb and the socket.

The current draw of the 100 watt bulb could be causing something in the power supply to shutdown from overheating. You would need a voltmeter to check while testing with your bigger bulb.

 

[pentaxuser]

Faulty 100W bulb? I switched to 75W simply because for colour printing from colour negs the exposure times were too short to measure using a Paterson colour analyser i.e less than about 4 seconds. I have had no problems at all with 75W and it is still fine for B&W exposures which are slightly longer but not inconveniently longer.

pentaxuser

 

[gamincurieux]

I agree pentaxuser, 75w is plenty for B&W, and a little more time is always handy for a bit of dodging/burning. However, for making my B&W contact sheets for color films (which I do purely as a cheap index for filing, I don't care that it's not color!) it will mean much much longer exposure times, which are already very very long.

Bob, the lamp is kind of on it's side. It's wedged in between metal holders, spring-loaded one at it's back to keep it in place... they're a little fiddly to replace actually. Funny you mention auto heat cut-out - on finding that the 75w worked I set about tracking down somewhere here in Melbourne that stocks this exact same lamp type, the Philips 12v 75w EFN 6853 A1/230. I jumped in the car & raced over there to get some more ($20 AUD each, cheaper than on the web!). I mentioned the problem to the guy at the store (http://www.gmtlighting.com.au), he suggested heat cut-out. I said I didn't think the M605 such a fancy model that it would have such a feature, but he said the heat may mean expansion somewhere that causes contact to be lost somehow.

Does the M605 do that, auto heat cut-out??

 

[pentaxuser]

I have the same M605 with a diffuser dichroic head and I am not aware of any heat cut out. If there is one it hasn't been triggered.

While I have never done B&W contact sheets from colour negs, I have done B&W prints from colour negs and I don't recall them taking that much longer - a matters of seconds only. I am puzzled as to why a contact sheet should take a very very long time

pentaxuser

 

[lajolla]

You likely need to replace your power supply transformer. The COLITRA transformer for the M605 is still sold factory "new" (for either 115v or 230v enlargers) at the Durst On-Line shop:
Dead Link Removed

 

[gamincurieux]

lajolla, why do I need to replace my transformer??

 

[lajolla]

If you can determine that the wiring in the M605 head does not have an intermittent short somewhere, than the problem likely resides in your COLITRA transformer. There is additionally a very small chance that the enlarger timer that you have controlling the transformer has developed a problem. good luck

 

[gamincurieux]

But it's a brand new RH Designs Analyser Pro that I paid through my nose to have sent down here, it can't be playing up already!!!

 

[Bob-D659]

If switching bulbs eliminates the problem, that doesn't sound like a timer problem. The timer circuit in the power supply is there to switch a relay to supply power to the bulb. To troubleshoot, you would have to reinstall the flakey bulb. Before you do, look carefully at the pins on the bulb. Are they pitted or dark? That could be caused by a socket on its way out. The socket in my CLS450 head has been replaced at least once, and so has the relay in the power supply.

 

[TimVermont]

If it lights reliably when first used, I would strongly suspect heat expansion in the socket causing an intermittent electrical failure. Also check for cracks in the socket.

 

[gamincurieux]

There IS a crack in that ceramic socket.

 

[Bob-D659]

That will do it. Time for a new socket.

 

[gamincurieux]

Geez, where am I going to get a new socket? Never mind because I'm in Australia, I have to wonder where anyone would get one anywhere. I mean, is this a Durst part, or is it something I should be able to sort out through some specialist supplier? Really I think I'd prefer to be using a 100w lamp. Any advice?

 

[David Grenet]

It's a Durst part, but also a standard part for halogen lighting. I can't recommend anywhere specific, but lighting stores might be able to help. Just make sure the socket you get is rated for 100W (most household halogen lights are much lower in power).

 

[yellowcat]

They are easy enough to find;

http://www.google.co.uk/search?hl=en&q=ceramic+halogen+socket&start=10&sa=N

 

[gamincurieux]

Many thanks for all advice ladies & gents, it is much appreciated & certainly steers me in the right direction

 

[Bob-D659]

http://www.topbulb.com/find/Product_Description.asp?intProductID=46396

has a good picture of the correct part.

 

[gamincurieux]

I got a new ceramic bit, trimmed it down & got it in there, working well. That said & after all that, I've decided to stick with 75w, probably less load on it in the long run (am thinking over the coming years), and less heat, and it'll give me slightly longer exposure times which is always handy. Once again everyone, thank you Paul