Omega D5500 Filter Wheel Rubber Repair

[ic-racer]

I have been using the D5500 heads for about 9 years and have not had to replace the wheels on any of my units. Rather than replacing them prior to failure, I wanted to see how they fail.

This head had clear rubber wheels and they pretty much crumbled on me last night.

This is how it looked when I took the head apart:

 

[ic-racer]

Next step, I removed the filter plates. I usually don't clean the filters unless they are severely dirty. Too much risk of breakage.

 

[ic-racer]

The filter wheels are held on to the motor shafts by SAE grub screws. Some shafts are "D" shaped and some are round. I removed the wheels and cleaned off the residual rubber:

 

[ic-racer]

I have a good selection of HO slot car tires. Jonny Lightning re-issue Aurora "Tough-One" tires seemed the best fit. The aftermarket "Jel Claw" tires #ST-2010 also fit well (they are not that good for racing, though).
http://www.jelclaws.com/cart.php?m=product_detail&p=19

 

[ic-racer]

They seemed to fit well without glue.

 

[ic-racer]

You can't really get to the grub screws on the shortest shaft motor without taking the motor out. Be careful, the motor is spring loaded. The little black axle-screws that hold the motor in place are unique to this head and made of 'UNOBTANIUM' ! I think the threads on the axle-screws are metric, because the motors are made in Germany.

When you take the motor out, a fiber plate falls out. This needs to go between the front of the motor and the chassis. There is a hole in it and one of the motor mount screws holds it in place.

 

[ic-racer]

I have had the motors and reduction gearboxes apart. From what I can tell there were two styles. The early style had straight cut gears in the gearbox and is noisy (like a vintage Ferrari gearbox). The later motors have helical cut gears and are much quieter.

 

[ic-racer]

Here it is all ready to go be put back together. Make sure the wheel assemblies are on the motor shaft in the correct position so they don't accidentally rub on two filters at the same time. There is very little tolerance.

 

[ic-racer]

BTW I never use the "WHITE" button unless I'm setting the lightbox calibration trimmers, as it chews up the wheels over time. The way it is set up, when you press "WHITE," it does not know how far each filter needs to go to get to the top, so it just runs them for a certain amount of time and the rubber wheels grind on the filter for a few seconds after they get to the top. If your lightbox calibration is way off or buggered, then the motors may keep running an grind/slip continuously until you shut the unit off.

Instead of using "WHITE" just punch in "O" for your filtration, that way the filters stop as soon as it detects white, without grinding the wheels.

BTW when I last checked (a little over a year ago) Omega was still selling replacement wheels and shafts. customerservice@omegabrandess.com

 

[Ed Sukach]

Good article!

I've heard that 8mm aquarium tubing works well.

Wish I knew about all theses fixes before i sprung for US$90 for the wheels from Omega.

 

[mgb74]

I have this same issue with a recently acquired D5500 and CLS head. Is it necessary to remove the bushings from the motors? I'm thinking of using some latex tubing if I can find the right size.

 

[darinwc]

Wow, I will have to try these. I wish I had seen this a few years ago.

 

[ic-racer]

I need to update this thread. After 4 years the slot car tires became "D" shaped or split. I currently am using silicone model aircraft tubing with success.

 

[AgX]

I would have looked for apt neoprene- or silicone-rubber tubings. I likely would not have thought of those IC-car tires. Good idea too. Though not so good as it turned out...


But if being busy with that assembly I likely would have at least considered sprocked wheels and toothed racks instead too.
But I do not know what is available from modelling or mechanics dealers.

Had you considered sprocket wheels?

 

[ic-racer]

d5500 roller

id 6.45mm 0.25393701" on 8mm 0.31496063" shaft
5mm 0.19685039" width
11mm od 0.43307087"

 

[mgb74]

I wonder if the 1/4" ID and 7/16" OD latex tubing from here would work? Alternatively, the .5" OD is a bit high, but would likely stretch down a bit if placed on a .31" shaft.

A medical supply store might stock it also.

 

[Mikey Antonakakis]

Just got one of my D5500 heads' filter drive repaired. Since the photos in this thread are dead, I thought I would add my own from the process and maybe a couple pointers for anyone else that needs to make this repair.


First a photo of the connectors going into the board on either side of the transformer to note the orientation:

To get the head stripped down, you'll need to unplug the two connectors on either side of the transformer, remove the bulb mount (two screws, not pictured), and snip this cable tie:

With those disconnected, it's pretty straightforward to get all the panels removed by removing the appropriate screws around the perimeter of the head. What I was left with was this state, showing just how bad the "rubber" wheels were. Mostly disintegrated, and what was left was extremely soft and sticky:

More photos to come.

 

[Mikey Antonakakis]

Another view of the assembly, showing the order and orientation of the motors. Should be obvious but doesn't hurt to have more photos when doing a first-time repair:

Don't do what I did when removing the filter plates. There's a stack of black plastic spacers mounted on a long standoff, with screws at either end. So, you can remove from either the diffusion box side, or the bulb side. I unscrewed from the bulb side of the assembly, and the filter stack was happy to sit there upright. Until it wasn't, and they all fell down. Thankfully none of them broke, but be careful! The ends of the standoffs have a shoulder that fits into the mounting plate to precisely align them. That friction fit was all that was holding them in place, and I took it for granted. Once you unscrew them, carefully remove the whole stack (if unscrewed from the bulb side) or one-by-one (if unscrewed from the diffusion box side. Note their orientation. Carefully set them aside, don't be like me!

With the filters out of the way, you can see the four screws holding the motor/filter mount plate to the u-shaped aluminum extrusion. You don't necessarily need to remove them, but I did to make it easier to access the motors and get everything cleaned up.

With those four screws removed, you're left with a simple motor subassembly:

 

[Mikey Antonakakis]

This view shows how the springs (used to create enough friction to drive the filter plates, as well as take up any wear/misalignment to keep a relatively constant force on the rubber rollers) are situated. Looking past the motors, you can see the green fiber spacers and their orientation.

Here's the method I used to safely remove each motor: squeeze the motor against its spring to release any radial force in the screws before removing them. They look beefy when they are installed, but they are actually something like M3 threads and would be easy to strip out or damage, and as @ic-racer pointed out, they are probably unobtanium unless you know someone with a Swiss screw lathe. Or maybe (very doubtfully) you could find them at McMaster-Carr or similar. The easiest thing is to not break them, so squeeze the motor until it's approximately in the middle of its range of travel before you remove them.

Once the screws are removed, to get the motors out by using your screwdriver to compress the spring, keeping the tension off the motor will make it easier to get the longer shafts clear of the mounting plate. Your fiber spacer will fall out, do this over a table. Also take care not to be too rough on the motor wires. They aren't extremely fragile but it's always easier to not have to break out the soldering iron:

A couple photos of the filter stack, as removed from the bulb side. Note orientation and the nasty rubber remnants:

To remove the rubber from the motor shafts (and the plastic pieces on the filter plates), I first scraped gently with a small flathead screwdriver to remove the bulk of it, then used acetone and paper towels to get the rest. Cleaned up much easier than expected, took maybe 15 minutes to do all three motors and filter plates. Note that I did not remove the extensions from the motor shafts; I believe the grub screw uses 0.05" hex key, but they were far too tight/slightly corroded in place and I would have just stripped them. I also would have had to deal with pulling the very tightly fit/slightly corroded into place extensions off the shafts, and gotten them realigned/properly spaced for reassembly. Unless you think you need to get into the motor casing/gearbox it is far easier to just leave them in place. I was left with this:

 

[Mikey Antonakakis]

I found some 1/4"ID-3/8"OD latex rubber hose at Ace Hardware, available by the foot. Home Depot had the same thing as a precut length, see here.
I needed some anyway for my print washer, so I saved a few inches for the motor repair. It might end up being a little too soft and slightly small in outer diameter. With the spring-tensioned motors, you can probably get away with a little larger OD - but if you go too small on OD, you might have the motor shaft extension piece of one filter rubbing on the adjacent filter. I also ordered some similar sized 8mm/11mm silicone tubing, and I've got my eye on some polyurethane fuel hose if needed, either the 1/4"ID-3/8"OD or 5/16"ID-7/16"OD size.
Anyway, here's the latex hose installed:

One last thing - cleaning the filters. They are definitely delicate, but after they survived a fall, and after I saw their state, I decided I would be able to be safe enough to clean them. They were dirty, I used some generic lens cleaner spray (altura brand from Amazon) and PEC-PADs. Here's the before and after of one of them:

As usual, reassembly is reverse etc. Just take care on the filter stack. My spacers looked grimey, so I cleaned them all with acetone before reassembly. And note that the standoffs they are mounted on have shoulders that need to go into the holes in the mounting plate! And take care not to cross-thread the motor mounting screws during reassembly; use a similar method to deal with spring tension as used for disassembly.

I am now working on replacing the light seals in my head, hopefully that will be done before the end of the day and I'll be able to report back on whether it was successful or not.

 

[mgb74]

Very helpful.

 

[ic-racer]

Nice pictures. Good to update the thread.

I have had my two D5500 for over 20 years now and the are still working great.

My most recent repair was to re-do the connector on one of the power supplies. The symptom was the filters motors would wander back and forth during the exposure. It made it seem like the was something wrong with the sensors in the mixing box. But, the issue was with the connector on the power supply. With years of plugging and un-plugging, at least one of the wires broke in the cable. I was able to open the connector, cut the end of the cable, and re-insert it into the connector.

 

[ic-racer]

Looking back, this image is from 2009. Last time I had this head open, the foam rubber was still in good shape. Though, it might need to be redone some time again in the future.

McMaster Carr was, and still is, a good source of foam rubber in the USA.

 

[ic-racer]

Be careful with the wires and the fan. Once, many years ago, I opened one of the head to find the wires fouling the fan. Totally keeping if from rotating. How long was it like that? Maybe a year or two. Good news is that after removing the fouled wire, the fan was fine, the motor was not blown. Fortunately I usually print with pretty short exposures, so nothing was damaged without the fan running.

How did I not know the fan wasn't working? My electrostatic air cleaner is pretty noisy, so I can't hear the fan in the D5500. One day after turning the electrostatic clearer off, I was surprised at how quiet the fan was in that D5500. Of course it was quiet...it wasn't turning!

 

[Mikey Antonakakis]

Quick update: 8mm ID silicone tubing just arrived and is far too loose. 6mm or 1/4” ID would probably be good assuming enough wall thickness. 1/4” ID latex is probably too thin/soft, seems like adjacent motor shaft will rub. Will give it a try, but going to try polyurethane next.