Durst m800 - issues with lifting mechanism

[negativefunk]

Hi everyone,

I'm new to the forum, and recently got back to developing my own film and hopefully printing after a long break.

I came across a durst m800 with a few accessories, and a few bits missing too.

The main issue I have now is with the lifting mechanism. The head tends to fall down, and the crank does not have any effect when trying to lift it back up.

I don't know how is the mechanism supposed to work so I am not entirely clear on how to see if something is missing. there is nothing blatantly broken.
It was allegedly working before the enlarger was shipped, so I suppose something might have been dislodged\lost when the seller dismounted it.

A couple of pics of the interior of the head are attached!

Thank you all

 

[negativefunk]

Sorted, albeit provisionally until I find a replacement.

The black gear actioned by the crank was slightly broken and didn't transmit the motion to the smaller one, that climbs the column.

 

[MrSidecar]

negativefunk,

how did you fix your issue? I have the same enlarger and the same issue, albeit not as bad as yours. Mine stays put once I find a height but the crank alone doesn't lift the head, I have to help it up while turning the crank.
I narrowed it down to the big black gear slipping on its axis, but apparently the friction is still sufficient to hold the head in place...

I have tried but can't find any replacement parts anywhere, so any fix however provisional would be very welcome.

All The Best
Sidecar

 

[negativefunk]

Hello,

My fix was not very elegant, but kept me going for the whole year so far.

I understand there are two versions of the mechanism.

One - like mine - where the big and the smaller wheel are part of the same piece. In my case it was the smaller one not holding up as a crack alongside the piece made it loose on the rail.
I did rebuild it (and some) with epoxi glue. It was meant to be temporary but so far, so good.

I spoke with a guy that had the two-wheels version. He 3d-designed a replacement for the little one and had it 3d-printed. apparently "conventional" plastics do not work and he had to find a service to print in nylon.
I might still have the 3d design he shared - note that I don't know anything about that.

A third option could be contacting people on local classifieds\national ebay where these enlargers are labelled as pick up only. Often the pieces don't sell so suggesting a split for parts may be of interest for the seller!

 

[MrSidecar]

Hello,

My fix was not very elegant, but kept me going for the whole year so far.

I understand there are two versions of the mechanism.

One - like mine - where the big and the smaller wheel are part of the same piece. In my case it was the smaller one not holding up as a crack alongside the piece made it loose on the rail.
I did rebuild it (and some) with epoxi glue. It was meant to be temporary but so far, so good.

I spoke with a guy that had the two-wheels version. He 3d-designed a replacement for the little one and had it 3d-printed. apparently "conventional" plastics do not work and he had to find a service to print in nylon.
I might still have the 3d design he shared - note that I don't know anything about that.

A third option could be contacting people on local classifieds\national ebay where these enlargers are labelled as pick up only. Often the pieces don't sell so suggesting a split for parts may be of interest for the seller!

Hey,
thank you for your reply. I was thinking about the third option as well. 3d print had crossed my mind, maybe you could send me the file the other guy shared.

 

[negativefunk]

Sure, here it is

 

[Randy Stewart]

The main issue I have now is with the lifting mechanism. The head tends to fall down, and the crank does not have any effect when trying to lift it back up.

I have considerable experience with the M800, including a few improvements. It does present a failing, and your problem describes it. The head is driven up and down the column by a crank which turns a set of gears located on the rear of the column. These gears mesh with two geared tracks running the length of the column. Unhappily these days, Durst made those gears and tracks out of some sort of nylon, which has hardened. The consequence is that it is common to chip teeth out of those parts. If you chip out enough teeth, that opens a gap in the mesh between the gear and track, which causes the geared wheels to let the head slip down the column. Back when Durst was still viable, you could order replacement tracks and gears at low cost. The tracks are held in place with a couple of small screws and easy to replace. Today, two problems: (1) Not available in the US. Maybe more so in Europe. (2) The Durst parts harden whether in use or stored, so new original parts are just as brittle now. I think I saw someone selling these tracks (3-D printed) on ebay not that long ago. Replacement gears, nylon or brass, should be available online.