Durst L1840 Enlarger 8x10 10x10--Everything you wanted to know...

Degroto,
From your previous posts I believe you have a CLS301 head and TRA 301 powersupply. I don't have manuals on those items, but I do have some pictures from the internet (though, if you could post pictures of your equipment that would be better)

The image below is probably similar to the TRA301 (again, a picture of your unit would be better).
The timer triggers the lamp on-off through the "timer input" socket. Do you have your timer's output cord hooked up there? Have you confirmed that voltage is present coming out of the timer when it is on and none when it is off. I believe the trigger voltages it needs to detect at the "timer input" socket are from 90V to 240V to get the lamp to go on.
Do you have another timer to try? Does the enlarger lamp go off when you unplug the timer from the "timer input" socket?
Attachment 121013

I'll have a look tonight. The strange thing is couple of years back I had it hooked up and it worked. But now it won't. I have the same thing is is shown here. The powercord of the times was cannected to the TRA301. But nothing went into the timer itself. Normally I would suspect something like that. But the only cable from the CLS301 head has that strange looking connector. But again I'll try again tonight and I will make photo's and I'll take notes. Thanks for the input so far.

Yes. My lamps (I bought two halogens to try of different power ratings) are rated for 240V whilst wall voltage is 230V. I will simply give them either 1 in 4, 2 in 4, 3 in 4 or full 4 in 4 half sinusoids. No chopping of the waveform but simply zero voltage startup on the half sinusoids. There might be a colour shift at the 1/4 setting but I'd hope to have a pretty even colour from the lamps otherwise.

The problem for me is that when the thyristor chopping circuits are employed they must start each partial waveform with a very steep dI/dt which must shock the filament. It would be a different story if they started at zero and then commuted their waveform. Perhaps I'm being a bit thingy here and I can revert to a chopping method later if need be.

I reckon if money were no object, I'd buy a full-on industrial dc power supply rated for the power and current and that would be the ultimate solution.

Depending on where you live, a regulated power supply may not be needed. I don't need one where I live.

When you do BW only consider a led lightsource. That’s the way I would go if my electronics or bulb’s run out. If you are doing color that’s a other story.

Yes, I believe LEDs have a very non-continuous spectral response. It reminds me of an American who taught me in a business school once reciting something about US submariners having weak bones after a prolonged stint at sea because of the poor spectral response of the early flouro tubes in the subs.

I'm using halogens for the continual spectral response specifically. I figure the costs of running them is insignificant.

The halogens are new and for the stage (theatre) industry. They should be available for the foreseeable future.

Cheers,

If you want to use your durst for sunbathing you surely have a point. For making BW print’s I can’t see the necessity of a wide spectral response beyond what’s required to expose BW paper.

Attachment 121146
Attachment 121147

I have connected the Tra301 and the Head301 the following way including the timer.
1) Timer powercord goes in the Timer socket on the Tra301
2) Powercord of the head with strange thingy goes in the long socket of the Tra301
3)The powercord of the Timer section (A on the photo) Goes into a wall outlet.

4) The powercord of the fan goes into a the Fan section on the Tra301.
5) The powercord of the fan section goes into a wall outlet.

In the timer I have nothing connected (see photo). This is probably where I go wrong. However I have put in the the powercord mention at 3) in the timer but nothing happens. The light is on and stay on. even when I turn of the timer.

What am I doing wrong?

Need a better shot of the back of the timer. Need to know which cord feeds the timer with power and which cord is the output from the timer to the enlarger. Also need to make sure the timer is not on some "Focus" mode where the enlarger light will always be on.

I will post new photos. In the meantime:
On the first photo: The powercable on the top left leads to the timer. The second powercable leads to a wall outlet. The third cable is from the Color Head 301. The 4th and 5th power cable are for the fan.

On the second photo is the back of the timer.The cable on the right goes to the powercable on the top right of the TRA301. The there is an outlet and an on/off switch.

Normally i would plug in the powercable of the enlarger in the socket on the timer. And the timer would go into the wall outlet. However the power cable of the color head is the rectangualar thing on the TRA 301.

I have reread the manual and I will try again tonight. I'll keep you guys and galls posted