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

So, how does it work? It reduces the light falloff at the edges, but the whole tube array has some inconsistency. I'm not shure how perfect I can get it. I suspect I will have to make due with something less than perfect.

It seems that the corners where the tube dives exits the light chamber are dark. Perhaps I might try some highly reflective silver paint in these areas.

The cosmetic bellows that hide the large 8" central column were all in bad shape. The outer fabric had separated from the inner pleats.

There are 3 cosmetic bellows. The top and bottom ones seemed to be the same size. The center one is the longest.

I used the same 3M "77" spray glue that I had used to construct my Century's bellows. However, this spray is not re-positionable. So, it was very difficult to get the bellows fabric to lie in the correct troughs of the pleats. The whole bellows cannot be spread out flat because there is a fabric strip on the back of the bellows that supports the column of pleats and prevents hyperextension. This fabric strip is sewn to every 4 or 5 pleats. To lay the thing out flat would involve removing this fabric strip and re-sewing it in place.

It would not occur to me to SEW a bellows because of the obvious light holes, however, this cosmetic bellows already had the fabric strip sewn to the back of it. So, to keep the front fabric in place I ran a line of black thread along each trough of the bellows. This was a lot of sewing, but it wound up looking better than the piece on which I had tried the spray glue.

Once fixed up, they easily compressed to a small size and can be removed or replaced without having to remove the column sides.

I really like 'before-after' photographs. Here are a couple showing the power supplies and the lower bellows.

Quote:

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Originally Posted by ic-racer

........The whole bellows cannot be spread out flat because there is a fabric strip on the back of the bellows that supports the column of pleats and prevents hyperextension. This fabric strip is sewn to every 4 or 5 pleats. To lay the thing out flat would involve removing this fabric strip and re-sewing it in place.

..... to keep the front fabric in place I ran a line of black thread along each trough of the bellows. This was a lot of sewing, but it wound up looking better than the piece on which I had tried the spray glue.

Once fixed up, they easily compressed to a small size and can be removed or replaced without having to remove the column sides.

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That's a very interesting solution. I had the same problem, and I had to remove the fabric strip and extend the bellows flat before I could reglue the fabric. Then I re-attached the strip. Sewing the folds sounds like a better solution.

Also, after I re-glued the bellows, I compressed it fully and let it stay compressed several days to acquire a "set", before I re-installed it.

I didn't know the cosmetic bellows could be installed without removing the enlarger sides. Good tip.

That small tag sitting on top of the power supply is actually the Durst quality control tag. It has a small, un-opened bag, with some fuses in it, stapled to the back.

From the way it looks, that little tag had been sitting on the power supply since 1988. All the other documents for the enlarger had been stored in a separate folder.

Now that I look at the photograph closer I can see some tape residue on the side of the power supply. So, I suspect the tag was taped there for 10 years or so, until the tape crumbled and fell off.

Quote:

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Originally Posted by resummerfield

That's a very interesting solution. I had the same problem, and I had to remove the fabric strip and extend the bellows flat before I could reglue the fabric. Then I re-attached the strip. Sewing the folds sounds like a better solution.

Also, after I re-glued the bellows, I compressed it fully and let it stay compressed several days to acquire a "set", before I re-installed it.

I didn't know the cosmetic bellows could be installed without removing the enlarger sides. Good tip.

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Yes, once it is all compressed nice and small it will rotate in the slot and come right out. (Didn't try it on the big middle one, though)

I scanned my L1840 Owner's Manual into a PDF file that I would like to distribute to all Durst owners, or potential owners, that don't have one.

I'd just post it here but the file is just over 6MB. Please PM me and I will send it out.

Just a note on the power supply that I forgot to mention when I was fixing it.

There are two taps on the power transformer primary side, intended for 220v or 240v. They are NOT MARKED on the transformer, but they are mentioned in the owner's manual.

My power supply came with the connector on the 220v prong (this is the way it is delivered, per the owner's manual).

My power main supply in my darkroom measured to be 240v. With this situation (ie 240v input to the 220v transformer tap) the printed circuit board voltages were slightly high. The shop manual stated 30v but I was getting 32v. Now some of the ICs on the board have an operating range from 15v to 32v, so this is getting close to the limit.

By switching my connector to the other prong (the un-marked 240v primary input on the power transformer) my voltages on the PC board dropped to about 30v, which was more in line with the voltages specified in the shop manual.

Here is a scan of the original sales record for my enlarger. The prices are in US dollars. The date was 1988.

Here is the location I decided for the 240/220v line. Again it is just wired with 12/2 wire and a 20A dual breaker. I need to thank Eric Summerfield for encouraging me not to tap into 50A line to my wife's new oven (which is just 3 feet from by eventual outlet location).