Ungluing Cracked Omega D5XL dichroic filter

[cyrus]

Does anyone know how to go about swapping out a dichroic filter on one of these? They seem to be glued in place so I guess I should somehow un-glue it. A solvent? Heat?

Also, the lifting levers on mine seem out of alignment. On the top set of lifting levers, when the one on the left is all the way down, the one on the right is slightly higher. I assume they're both supposed to be even so they lift the head evenly but as it is, I can't attach the right side arm to the head because it is set higher than the screw hole, when the left side arm is screwed in. This enlarger was abused and misaligned when I got it. The teeth on the rear evelvation gears were totally shredded, and that doesn't happen to an Omega unless it is badly misaligned. I have absolutely no idea how the guy who used it before me managed. So I am guessing somehow he set it up wrong from the get go. There is a hex nut on the lever, which I think can be loosened to raise/lower it?

[vinny]

Yes you can adjust the levers to get the head to lay flat. I don't know about the filters but considering the heat in there, more heat won't be of use.

[Len Middleton]

cyrus,

The lifting arms are secured onto the cross rod connecting the two sides together with socket head set screws (i.e. use Allen key to loosen or tighten). The end of the cross rods is knurled to help the set screw prevent the lifting arms from turning relative to the cross rod.

You will need to loosen the set screw and remove the arm to reset it into the correct position.

On another note, there were different sets of lifting arms for condensor heads and colour heads, but given your comments, it does not sound like that is your problem.

I think vinny's comment on heat makes sense.

Where are you getting the replacement filters from, might they provide some insight on how to remove the old ones?

Hope that is helpful,

Len

[cyrus]

Thanks Len & Vinny
I have another color head that I want to swap filters with, so I was hoping there is a way to extract the filters without damaging them. I understand that B&H sells these filters too, but not sure if the new ones include an instruction set. Another option is to simply remove the entire filter assemby and swap the entire filter plate instead of the filter itself.

[Greg Blank]

Hi Cyrus;

I work PT at Omega and have been doing the Lamphouse repairs for a while now. I usually break down the complete lamp house in my price for doing the repairs, it is the best way to get to know the machine, plus you can add lubrication and remove the typical many years of dirt that accumulates. Everything is lubricated with Vaseline. The adhesive that is originally used can be removed with 99% Isopropyl alcohol.

I always take the filter arms off the spindle to reglue the filters. The new or "cleaned" filter is reglued using Pliobond which is a high temperature adhesive and contains Methyl ethyl ketone. The filter is located on four small metal tabs. It is important to sand the tabs to remove the old adhesive and reseat the filter....otherwise it will most likely drop off or sit at a different angle than the way intended.

Omega has diagrams for proper position of the arms, you should email them at customerservice@omegabrandess.com

The arms could be misaligned for multiple reasons...you have the D shaped spacers on the arms? These brace the top set to the chassis and lower set, I seem to recall. Though there is only one proper set af arms depending on the Chassis, there is a different horizontal rod length if using a Dichrioc head versus a Condensor. Customer service should be able to provide the length, both top and bottom horizontal rods shold be the same.

If your gears are stripped, this happens if the head is tightened via the small knob and then someone winds the enlarger up or down aginst force. Sometimes also when in transit the enlarger mis-seats on the column and then is wound up or down. Omega sells replacement gears for around 22.00 each that can be installed as replacements, the replacement gears have a brass bushing and a set screw for easily being installed.

If this is too much for you to do, you can send at least the head in to Omega and we still offer this service, we will estimate it an get your approval prior to the repair.



Does anyone know how to go about swapping out a dichroic filter on one of these? They seem to be glued in place so I guess I should somehow un-glue it. A solvent? Heat?

Also, the lifting levers on mine seem out of alignment. On the top set of lifting levers, when the one on the left is all the way down, the one on the right is slightly higher. I assume they're both supposed to be even so they lift the head evenly but as it is, I can't attach the right side arm to the head because it is set higher than the screw hole, when the left side arm is screwed in. This enlarger was abused and misaligned when I got it. The teeth on the rear evelvation gears were totally shredded, and that doesn't happen to an Omega unless it is badly misaligned. I have absolutely no idea how the guy who used it before me managed. So I am guessing somehow he set it up wrong from the get go. There is a hex nut on the lever, which I think can be loosened to raise/lower it?

[cyrus]

Thanks Greg! That was very useful info.
Is there an exploded manual of parts for the dichroic D II head somewhere I can use?

[ic-racer]

I restored one of these and put my notes here: http://www.apug.org/forums/forum43/67980-converting-super-chromega-ii-120v.html

I used silicone glue to hold the glass in place. But if I did it again I'd do it the way Greg listed above.

[cyrus]

Actually I just swapped the filter plates with no problem. I lubed the filter plates and cams and now just have to replace the rubber basket , and the weather stripping in the back of the lamphouse. Turns out the yellow filter wasn't cracked after all, the glue job on it was just a mess and what I thought was a crack was actually a thin line of glue that went across the filter face. Oh well. Having a second lamphouse for parts is a good idea! I noticed that the two are actually not identical. One lamphouse is black on the sides, the other is grey. The bolts that connect them to the chases are also different: one set is wider than the other. Anyway the only thing I baby figure out is why the magenta stood at 167 instead of 172 like the cyan and yellow. The magenta cam just won't go any further

[cyrus]

OK so my spell checker screwed up my last post:


Actually I just swapped the filter plates with no problem. I lubed the filter plates and cams and now just have to replace the rubber Gasket , and the weather stripping in the back of the lamphouse. Turns out the yellow filter wasn't cracked after all, the glue job on it was just a mess and what I thought was a crack was actually a thin line of glue that went across the filter face. Oh well. Having a second lamphouse for parts is a good idea! I noticed that the two are actually not identical. One lamphouse is black on the sides, the other is grey. The bolts that connect them to the chassis are also different: one set is wider than the other. Anyway the only thing I can't figure out is why the magenta stood at 167 instead of 172 like the cyan and yellow. The magenta cam just won't go any further

Oh BTW did I mention I found a dead dried-up lizard in this enlarger? I have no idea what the previous owner was doing to this poor thing!

[ic-racer]

The black housing should be newer. If I remember correctly the ridges you feel with your fingers when moving the dials are the actual gear teeth. That means they are exposed and can be damaged, perhaps that is causing the binding. Seems like a good project where you can strip them and build a real nice one with the best parts from each. You know about the mechanism where you can disengage the teeth to "zero" the dials at any color setting? (Zeroing a filter pack). If you are printing B&W this will just screw you up. Try un-zeroing the magenta.

[cyrus]

Thanks ic-racer,
I did zero it by loosen the screw on the bottom of the counters and re-engaged the counter while it was at xero) so the magenta starts at zero but does not go all the way to 171 as do the other filters. It stops at 167. I sort of guessed at the proper way to zero things but I don't know if that's the reason. I'll have to read up on this

[cyrus]

It would suck if the reason the magenta doesn't turn all the way is damaged gears because taking apart the gear mechanism without an exploded parts diagram would be a hassle!

[Greg Blank]

If you look at the front of the housing, there is a door that comes away, the large gear wheels engage the numerical wheels that register the change the filter arms make as they pass the port that the bulb light shine through. Small amounts of the cement across the glass of the filter are non consequential, the light passes and is mixed in the box- though I personally am careful I see sloppy gluing come back all the time. The numerical wheel assembly can be reset, the only thing I can say is fiddle with them until all are at zero, then set the arms at the loweest spot, zero....and then carefully put the assembly back in place....the number like to jump...If you get all zeros thats great, if you spin the filters and all go to 170 even better, if you then go back to zero and they all staid at zero perfect. Perfectlon seldom happens. ;)



The black housing should be newer. If I remember correctly the ridges you feel with your fingers when moving the dials are the actual gear teeth. That means they are exposed and can be damaged, perhaps that is causing the binding. Seems like a good project where you can strip them and build a real nice one with the best parts from each. You know about the mechanism where you can disengage the teeth to "zero" the dials at any color setting? (Zeroing a filter pack). If you are printing B&W this will just screw you up. Try un-zeroing the magenta.

[Greg Blank]

You will need to be patient and ask Omega for the Dichrioc Parts daigram.


It would suck if the reason the magenta doesn't turn all the way is damaged gears because taking apart the gear mechanism without an exploded parts diagram would be a hassle!

[cyrus]

Yeah I figure 167 is magenta enough for my purposes. Im dine with this particular project for now.

[JoshW]

What do you glue them back in with that can withstand the heat ?

[d.s.]

The glue is "Pliobond". It is available in 1 FL.oz. tubes, which is more than you'll ever need. I found the Pliobond at a local hardware store.

See Greg's post #5 above for important details.

i wash the filter mounting tabs with 91% Isopropyl alcohol before and after sanding. Let the tabs dry, I then used a straight pin to place a small drop of the glue on the filter mount tabs, then placed the filter onto the filter mount tabs. I then pressed the filter down gently with a q-tip into the dot of Pliobond glue.

I recall that the filters are a "front or first surface" type of filter and it must be mounted in a specific way. I believe that the front/first surface side faces the light, but I'm not certain, because it was many many years ago that i replaced a filter. So i advise seeking that information before gluing a filter in. Greg may be able to shed light on this.

Reflections on the front/first surface side will have one edge to them. Reflections on the back side will have a double edged look to them.

Hope this helps.