View Full Version : Patterson Orbital Processor Help

26-Aug-2006, 05:04
Hi guys,

I just received my first large format kit this week, i'll put up another post about my camera and what not so I can hopefully quickly get up to making some quick test exposures to ensure everything is fine.. for now though I'd like to find out how to use the patterson orbital processor that i brought to develop 5x4" films myself.

I have developed my own 35mm and medium format black and white photos, so have all the chemicals ready.. I've gotten the processor.. it does NOT have the cuts in the bottom that i've heard some people recommend.. I guess I may have a go at doing this with a stanley knife though i'd be worried of making a hole and making the tray effectively useless.

Anyways I don't have any instructions I was wondering if someone could point me to a page describing how to use it or give me a quick summary... It has the red tees, i see the holes that go into the base for it, i take it these are so the film can rest on top of these off from the bottom?

It also has the seperate dome base, can't quite see whether this is just to go underneath the main tray so you can kind of agitate the tray in a circular fashion.

I see that you can fill from the centre in what is hopefully a light tight system, the top left corner of the tray has an arrow in it, not sure what this is.. the main question i guess is how can I empty the tray of developer before putting in my stop, fixer etc... does this just pour out of the top the same way you pour it in? going in no problem but coming out of here strikes me as being very messy and difficult to get the liquids back into their containers for reuse. Or can you pour to the corner with the arrow and somewhere there is some network of holes to drain out?

That's about it i guess... Your help is very appreciated.

Steve Kefford
26-Aug-2006, 07:31
Anyways I don't have any instructions I was wondering if someone could point me to a page describing how to use it or give me a quick summary... It has the red tees, i see the holes that go into the base for it, i take it these are so the film can rest on top of these off from the bottom?

These tees are to keep the sheets from riding over each other. The film does rest on the bottom. Some score grooves on the bottom to aid flow underneath. I have used a few strips of silicon sealant to raise the film slightly.

It also has the seperate dome base, can't quite see whether this is just to go underneath the main tray so you can kind of agitate the tray in a circular fashion.

Spot on.

I see that you can fill from the centre in what is hopefully a light tight system, the top left corner of the tray has an arrow in it, not sure what this is.. the main question i guess is how can I empty the tray of developer before putting in my stop, fixer etc... does this just pour out of the top the same way you pour it in?

Empty the liquid through the arrow.


26-Aug-2006, 14:37
I like the idea of silicon sealant to make raised ridges rather than a knife to make valleys in the existing base.

Is this silicon safe to not come off when being exposed to all the developing chemicals.. you couldn't take a snapshot of your handy work on the processor? :)

I guess all silicon sealant is pretty similar, i'll keep an eye out.

Colin Robertson
26-Aug-2006, 16:39
Take the lid off the processor. Inside, you'll see four holes in the base. FIRMLY put a red peg in each one. One sheet of 5x4 goes in each corner, edges tucked under the pegs to stop 'em sliding around. The inner floor of the processor is smooth- so, if you have film loaded then pour in chemistry through the top there's a danger the film will stick to the floor as it gets wet (done that). The idea of roughening the floor is to let the chemistry flow under the film. My approach is, in the darkroom I presoak the film in a tray for a couple of minutes, then load it into the orbital wet. This solved it for me. Once loaded, put the orbital on its base. Pour chemistry in through top, slowly roll it around the base during processing- this keeps sluicing the dev over the film. Drain through the corner marked with the arrow. Great tool.
Just be careful taking the film back out- it's such a tight fit you dont want to scratch up the film at the last step.

Clueless Winddancing
26-Aug-2006, 16:44
The temp chart is a drift-by monograph. As the temp cools during processing, make the temp a little warmer so that as it cools it will "just" drift-by the intended temp and then it will become a tad cooler still. Were you to try some litho 4/5 you could have "good" red light to watch things work out. A stabilizing water bath would help for more critical temps.

2-Sep-2006, 11:05
Thanks guys, still not had chance to shoot or develop any black and white slides yet..

Sorry Clueless, I'm not sure what you mean.. I'm roughly aware of temperature control of my chemicals whenever i've done developing in my patterson tanks.. what is a drift-by monograph..


Clueless Winddancing
2-Sep-2006, 18:48
In my new location I've not "found" those instructions yet. Lets say that 68 F is your time for 7 min. And that you've temped the tray to 72 F, it cools down naturally "drifting to 68 F in 4 min. By having the developer a little warmer than 68 F it will drift down to 68 F through out the majority of the film developing time. ( Were you to simply start out at 68 F the cooling down would result in less development than you had a right to expect.) It is usually important to have consistently repeatable temperatures so that you can make intelligent changes towards results that work for you. Have your subsequent chemicals warmed to the desired working temp further aids predictable results.
Some developers are more independent of temperature than others. To have control for a predicable outcome one usually must manage the variables.

6-Sep-2006, 13:10
Ok, I've just tried my first home development of Ilford Delta 100 in fotospeed chemicals. This is the delta 100 that i wasn't sure if i ruined by opening the pack not in the dark..

I took 4 rubbish shots this afternoon and finally got round to developing them this evening.. loading the processor in my changing bag was a bit tight, but i managed it ok... i'd had trouble trying to load the film in the slides for the first time in the darkness as well but i'm sure it'll get better over time.

Temperatures were perfect with the water and room being near 20 degrees.. i started development and as instructed delta 100 was going to take 13 minutes with my 1+14 mix of developer.

I had read conflicting reports on how much liquids to use, the seller saying you can get by with 100ml, others saying up to 1600ml.. i settled on 500ml as i already had stop and fixer to this amount as its what is needed to develop 35mm and medium format in my tanks.

500ml seemed to be ok, i found it hard to move the processor on its base as i was doing this on a counter covered in plastic covering.. the base was too keen to move with this plastic covering so it made it hard to do.. if you jerked it too much there were small spillages out of the arrow corner, luckily being caught by this plastic covering.

Normally i agitate once a minute for about 10-30 seconds each time, similar to the instructions off of ilford's site.. i wasn't sure if this would suffice for the processor so i ended up agitating during development for the entire time... i started to see the appeal of an automatic mechanism to do this, especially considering the difficulty i was having doing this.

After completing i drained the developer spotting that it should pour small enough to go into my small funnel when i poured the stop and fixer back into their containers.

loading up the stop and fixer i did it for the normal times.. i err on the side of caution here giving 1-2 mins stop, and at least 4 minutes fixer..

Then i followed the ilford recommended way of washing giving up to 4 seperate loads of water, increasing amount of agitation done in each one.

Finally i got some fotospeed rinse aid, made 5ml to 700ml water.. slightly more than recommended... poured it in, and made the room steamy to get rid of any airbourne dust, ready to hang the negs to dry as i usually do... in my bathroom.

Lid off and i saw that i could see images, development had clearly done ok... i could see some issues as well which i assume are the light leak damage i did when opening the pack.. perhaps something else as well..

The negs were stuck to the bottom as i've yet to try and mod the base the developer, for this first time.. i could really do with some pictures of someones that they've already done it in, just to be sure..

Wearing the gloves my finger nails could get under the negs and peel them up, only small amount of this was needed and then the whole neg came up.. the rinse aid and water was still in the processor, as recommended by ilford again...

For some reason i didn't spot at this time and proceeded to start hanging them away.. it was only later i noticed that they weren't dripping clean... they were dripping a purple/black liquid, all in my bath... I was used to thinking/hoping that by this time of development, most of the chemicals that are bad have been rinsed away and so the slight drips into the bath to be rinsed down aren't a problem... these though looked horrible... thankfully rinsing them away showed they weren't particularly staining the white plastic.

My question is, what the hell is this stuff? Is it as toxic as most other things in development land... what's caused it..

I'm letting them dry, and its getting better.. in the end i decided to blast each negative with the shower to get the most of the purple stuff of.. its clear that only one side is giving this stuff away.. not clear whether its the exposed side or not..

Is it because the negs have stuck to the bottom... i placed the exposed side up thinking that any damage done by sticking to the bottom shouldn't hurt the image too much...

Does both sides of the film need fixing, and has it being stuck to the bottom stopped this occuring on one side and that is what is dripping off?

After drying are these negs going to be usable or will they remain sticky, and potentially purple staining?

Basically help!!!! :)

I've started doing some developing inside, having lost the place that i used to do developing in... i'd refined everything down so that few spilling occured and i could manage everything reasonably well.. with this potential staining problem happening i dont have much confidence in doing this again, for fear of staining something.. and for worries of it being toxic stuff.

That's enough i guess.. thanks for your time.. your help is really appreciated... i wont be trying this again till at least the weekend.. and even then maybe not depending on my odds of not letting it happen again.


6-Sep-2006, 13:45
"My question is, what the hell is this stuff? Is it as toxic as most other things in development land... what's caused it.."

I believe what you are seeing is the anti-halation (sp) dye coming off the back of the negative. Since the negatives were stuck to the bottom of the processor, the chemicals and water could not get to the base of the negative to wash the anti-halation(sp) dye properly.

If you wash both sides of the negatives in an open tray after you complete the processing, the dye will wash off. The don't believe the dye is especially toxic.


6-Sep-2006, 15:17
Thanks Brandon.. thats kind of what i thought i just didn't know of its name, or if it existed.. i'll definitely be looking into the modding of the base..

Anyone else ever have similar troubles when their negs stick to the bottom.. does this go nearly completely once the tray has been modded?

Any other confirmations on its relative staining, toxicity.

Cheers, just going to get the negs in now they're dry they dont seem particularly staining, only near the hanging pegs where they've stayed slightly wet.

6-Sep-2006, 15:32
well i have the negs in a sleeve... there are some lines of varying tone where clearly something wasn't even during development, or fixing.. also the negs still have a very clear purple tone to them.. clearly a lot of the dye remains attached.. perhaps the chemicals are needed to really get at that surface to strip it properly??

I did rinse them vigorously in the shower to try and stop the dripping of purple... so what purple is left on wasn't coming off under fairly heavy pressure of the shower.

At least some images have been obtained... sadly my scanner can't scan them properly!!! :( i'll have to try.

6-Sep-2006, 17:18

If you take them out of the sleeves and let them sit in water (3 baths @ 5mins per bath), the stain should clear. You do not need water pressure, just a good soaking. Once the stain has cleared, put them in a bath with your wetting agent and hang them to dry again.


6-Sep-2006, 18:29
Thanks Brandon I may have a go at that.. i've got one of my first scans online here


Its come out pretty well.. i had a problem with my negative holding pegs.. usually they clip on where there is no image.. as i was fiddling with them a lot i put them on over the image, its caused some issues.. will have to look into that for the other hangers i get to properly support at least 4 negs drying at a time.

I had to leave the neg in the medium format holder and scan both sides, joining them together to get this image.. new scanner will be required!! :)

Anyways its late.. thanks for the help.. hopefully next time will be no problem..

as an aside it looks like the film hasn't been too badly damaged by the peak i gave it.. thankfully i left it in its black bag when i did peak.. hopefully the rest will look ok..

I'd still love to see some shots of modded orbital processors to show me the way to fixing this problem ever happening again.


Barry F
7-Sep-2006, 00:29
Hi JimBob,

Another UK member here. So glad you raised this topic as I,too, am about to start processing my own 5x4 monochromes in a Paterson Orbital.

I have a book by Frances Schultz and Roger Hicks in which they actively promote using the Orbital having 'scored' the base with a battery-driven 'Dremel' tool to increase the flow of the chemicals on the underside to remove this anti-halide coating efficiently (sorry no pics). Methinks that's my next step as I don't fancy the idea of using silicone strips.

The instruction manual, and Schultz and Hicks, maintain that 100ml of each liquid is sufficient to process four 5x4 negs with continuous agitation. The 'mound' at the bottom of the Orbital has only one purpose but two methods to achieve it - agitation! Because of its dynamic shape agitation can be done manually or mechanically via a motorised attachment on top of which the Orbital sits.

I currently have a spare Orbital and motor if you are interested in purchasing them, plus I would, as a one off, photocopy the instructions for you if you send me a pre-paid SAE.

Hope the above helps.

Clueless Winddancing
7-Sep-2006, 05:18
Barry, would you properly identify the publication about the Orbital by Schultz and Hicks? TIA

10-Sep-2006, 08:47
Barry.. it'd be great to know the name of the book with this mod described in it..

Also if anyone out there has a modded patterson orbital processor could you please take a picture and upload it as a guide for us about to do it..

what is the basic description... diagonal cuts along the base spread out by 1cm or so.. how deep a cut is needed? I've seen mention of some talking about using sandpaper first, why is this?

Is gently scoring it with a stanley knife or equivelant going to be ok... i'm just really nervous at puncturing a whole in it.. i guess only a mm or so depth is enough?

Sanding after cutting perhaps will smooth off all the edges so u wont scratch the negs whilst processing..

Cheers.. going to try a forum search but am sure have tried this before.

Pete Watkins
10-Sep-2006, 11:54
Jim, if you've got a branch of Hobbycraft near you, don't know what part of the U.K. you live in, they sell craft bits that look like beads cut in half. Superglue some of these to the base of the Orbital processor and you're on the way.

10-Sep-2006, 13:13
Interesting Pete.. I'll amend my details with my location.. i'm in Nottingham anyways.

Don't suppose again that you have a picture of your mod?

I'll do a search on the nearest hobbycraft.. what is the normal use of these half beads?

I guess super glue is tolerant of the developing chemicals and can withstand them?

Barry F
10-Sep-2006, 23:34
Clueless and Jim,

The book I was referring to is: -

Medium and Large Format Photography: Moving Beyond 35mm for Better Pictures
ISBN: 0817445579


Pete Watkins
11-Sep-2006, 00:42
Jim, these half bead things are for those idiots who watch daytime TV and call themselves "Crafters". They cut up bits of paper and glue sutff to the pieces, sell them as hand crafted greetings cards. I'm married to one, spent a fortune and sold sod all. I've had no problems with Superglue, all the chemicals that we use are well diluted and I doubt if you'll have any problems. Hobbycraft are expanding but if there is no shop in Nottingham there is one in Tamworth, I think that they have a website. Good luck, Pete.

13-Sep-2006, 05:23
I use a sharp blade to gouge the bottom of my Orbital in some sort of regular pattern. I had tried 4 "dud" non-exposed sheets before without the gouge and they /did/ stick to the bottom. With the gouging the slight relief prevents this from happening.

I develop using 150ml of solution and only intermitent agitation (10-20s per minute) and have nice evenly developed negs.

I've seen reported that too much agitation can create unneveness around the position of the two "blades" on the inside of the lid; I suposed that the turbulences from these fins must have some sort of impact...

24-Sep-2006, 06:37
Thanks to Pete Watkins, I'd had a go at modding the orbital processor as he had with the small beads on the base.. i ended up just using the adhesive they came with.. I guess I can super glue them if they start to come off.

I developed a set of test shots last night.. i've also acquired the automatic base and so developed with that.. no mess and nice to be able to be a bit lazy..

The shots have come out with a few problems on them again though..

They didn't stick to the bottom and came out clean, not dripping purple... here are the shots


Most have a light leak, or brightened area or two... when i took the lid off after washing one of the negs had escaped the confines of its corner, I don't know when this happened, or how.. i assumed due to the tilts to drain it out...

I also left the auto base on all the time as i was worried that at 150ml the developer wouldn't be touching everything unless it was being agitated..

I've heard about the lines on the lid potentially causing problems.. do they look like this??!

I've got a polaroid back now, and after a mistake and messing up the first one i've took 1 successful shot indoors which looked fine... I need to go out in the sun and shoot a few more to ensure its not the camera causing these marks...

Then i'm left with the film/film holder (slide)/developing as what could be causing the problems.

24-Sep-2006, 06:37
buze, how intermittent is your agitation.. perhaps i should turn on and off the base whilst i'm doing it in a similar frequency..

Pete Watkins
24-Sep-2006, 07:16
Hi Jim,
This is either flare or are you pre-washing Ilford film? DO NOT pre-wash Ilford film. If you pre-wash the stuff you will get uneven development, bin there, dun that.
Best wishes,

24-Sep-2006, 07:23
light levels were very low for all of this... it was approaching dusk... i need to give the lens a good clean to perhaps remove any possibility of problems..

i'm following ilfords instructions, developer is the first thing to touch the negs..

the only thing i worry about is if its me touching the film as i'm loading/unloading it... sometimes i do this by touch to feel that they're loaded correctly.. wouldn't expect it to do much though.. i've always been so impressed by how tolerant film is to abuse.. to a point anyways.

Not sure what pre-wash is, dont think i'm doing it :)

I still wonder if my handling of the film/slides is the problem.

Pete Watkins
24-Sep-2006, 07:32
I might be paronoid but I always wear vinyl gloves when handling film and chemicals. Clean up a piece of brass and then handle it, see what the sweat in your fingers has done to it. I learnt the hard way, I had to have a few days off work after using selinium toner without gloves (it might have been my cooking, but I doubt it). Vinyl gloves, Sainsburys, Homebase and B & Q all stock them. The worst thing that can happen now is that you discover that you are allergic to vinyl.
Good luck,

24-Sep-2006, 10:06
I have some latex gloves that i do use whenever handling chemicals.. on one hand only usually with minimal contact with the other hand... they're powerdered on the inside, not sterile but seem to do ok..

Do you recommend wearing the gloves when loading/unloading film .. i'd worry that losing that bit more tactile feedback would make it more difficult.. i also seem to need to use my nails to grab the film to pull it out of the slide.. i still seem to pull up too often and am forced to continue pulling away from the slide bending the neg a bit as it gets stuck to slide out if you pull it away from the slide only slightly.

I'm sure this could be the problem, i'm just a little shocked as i've found rollfilm to be suprisingly robust in this manner of handling.. only once did i get a real wrestle trying to load medium format on a reel.. hands got so sweaty and really struggled forcing it in.. in the end i swopped for a reel that had more obvious guides and did it quite quickly.. a few frames got damaged but this was a lot of handling.. i'm always being quite careful handling the sheet film.

I do pull the sheet film out of the pack by only pulling apart the 2 cardboard pieces enough to let the sheet film come away cleanly.. don't know if this could be scratching them on the way out..

I'll try to improve.. practice practice practice..

Colin Robertson
24-Sep-2006, 11:03
Hi Jim. There are two or three issues here.
First, if you have a motor base let it run continuosly. The orbital processor holds a small voume of chemistry, and the constant agitation keeps sloshing it over the film. It isn't really suited to intermittent agitation- you might just reduce developing time by ten percent.
Next- vinyl gloves beat latex. Much less risk of allery. Having said that, you should be able to handle the film without damaging it. Just wash and dry hands properly before handling film.
Next- and most importantly. The shots you have posted look like they have suffered light leaks, not processing errors. If your camera is a Shen Hao it pobably isn't very old and should be in good shape. Your film holders are more likely to be at fault (Or, just possibly, how you seat them in the camera). What kind/age are they??

24-Sep-2006, 12:22
I've had a look inside the bellows with a torch in a dark room.. annoyingly there seems to be a lot of pinhole leaks in the corners of the bellows.. I was wondering if the bellows SHOULD be perfect and completely light tight or are the extreme corners of each pleat ok to leak slightly as the light is so little and will be occluded from the film/lens by the pleat it is the corner of?

How can you go about fixing this.. I could try with tape but being on the corners i imagine its going to have a fair amount of stress.. its the Shen Hao one, can you just replace the bellows?

May start another thread about this one.. don't think this is the problem, as they look so small that surely they couldn't have such a drastic effect? that's my inexperience i guess, or optimism :)

Colin Robertson
24-Sep-2006, 13:22
Just been to flickr and sen the pics of your Shen. Looks older than I expected. YUP- if you can see pinholes in your bellows then that exactly explains the problems with your posted photos. I'm been shooting LF less than a year, so I have no idea if they are repairable or if you should replace. Post a new question and drag in some experienced folks. . .

27-Sep-2006, 11:09
I agitate by hand on the "plastic" base. I do 10 "turns" at a speed gentle enough so that I cannot hear any sloshing inside; it roughtly takes 15 seconds.
The rest of the time I put back the orbital in the water tank that I keep at 24C (the paterson floats nicely), so that the dev stays roughtly at that temp too.

I have not seen the "blade" streaks so far on film, but I have seen it on paper developped in the same orbital ! I think that it happends if the material you develop tries to "float" in the fluid; 150ml of solution seems not to be enough to raise the film high enough to touch the blades, but more solution might (I used quite a bit more for paper, next time I will use a smaller amount and see if it helps)

25-Dec-2008, 16:23

I recently got second hand orbital processor. It is fine, onle the red 'pegs'(?) are missing. (i am not sure what is right word forthem, but those things that keeps sheets from moving during development).

I have no idea what is the shape of the original ones. So far i have thought to use screws instead those red 'things'

If the only function of these 'things' are to keep sheets from sliding, then screws would work fine. But if they have some kind of clips that prevents sheets from moving upwards, then i have to figure something else.

Any suggestions?

Clueless Winddancing
25-Dec-2008, 19:10
I've just imaged the thing and sent the images to Jukka......
I've never sent data to be filed. If you think it worthwhile to see what all the discussion is about the images can be sent, reduced, and implantedbut not by me.
While I'm at it I'm going to try to scan the manual and the time/temperature monograph.
The manual is in several languages, the drawings are very clear. The next step is up to one of you.

Justin Cormack
26-Dec-2008, 16:08
The Orbital is supposed to be used with continuous agitation and a small quantity of liquid. I have had uneven development with intermittent agitation.

26-Dec-2008, 16:13
About modifications: I have read a lot of discussions from the net where everyone suggest to make some "canals" to the bottom of the orbital. Or to use silicon tape etc.

But what kind of pattern is good? Just a random?

All photographs of your modifications are really wellcome :)

26-Dec-2008, 16:27
I have no photographs (no need). I randomly scratched the base until it was no longer shiny. I used a dish scrubber I think. No channels or canals. I never got around to digging canals.

I use 300ml of solution, and I don't use a base, I sit the orbital flat on work surfaces, tilt each corner to agitate and ensure even coverage. This means I can develop four sheets of 5x4 with pegs without any floating issues.

26-Dec-2008, 19:35
I use an Orbital for my 4x5s and 8x10s. I've placed dots of silicon sealer on the botton of the processor to keep the film off the processor floor. I've processed many hundreds of sheets and the dots are still holding strong.

I also don't use the base, but rather place the processor on a flat table and agitate by lifting the edges slightly.


26-Dec-2008, 21:39
Have a look at the "Processing Tank Issues" thread on "Darkroom: Film Processing & Printing". Most of the info is there. Also search "orbital.
Main issues: Cut the fins off - they create eddies which streak the film. Use a Dremel engraver to put zigzags on the bottom so that the film won't stick. Use and throw away at least 150 ml chemical (that means doing everything twice) because an 8x10 area exhausts that much chemicals.

Tim Meisburger
27-Dec-2008, 06:42
I use one all the time. I made new pegs out of golf tees, but I guess screws would work fine, as long as the metal does not have some weird reaction to the chemicals (stainless screws should be fine). You can use anything to scratch the bottom of the tank, randomly or in a roughly drawn one centimeter grid. There is a website with instructions for operating an orbital (google roger and francis and paterson orbital). They recommend 60ml of chemicals for four 5x4 sheets. I use about 80ml, and that works fine. I also use the manual base and continuous agitation.

Good luck, Tim

8-Jan-2009, 00:08
Thanks everyone!

I have now screws that should work as original red pegs. I tried to find plastic golf tees or golf markers, but had no success on nearby shops.

It seems to work. The 4x5 negative moves a bit sideways, but I guess that it is not a problem?

I will soon put online the manual scans that Clueless Winddancing sent.

By looking pictures at the http://www.rogerandfrances.com/photoschool/ps%20how%20orbital.html it seems that there should be some extra space when 4x5 negative is fitted to the Orbital.

12-Jan-2009, 01:55
Now I have first real test performed.

It works fine except it seems that I made my 'pegs' bit too thick.
At first, I was concerned about the lateral movement of 4x5 sheet, which was about 5mm sideways. So I made my pegs thicker. It feeled a good approach. However, after few positive tests, I got some failures: The pegs does not allow any free movement, so if film sheet is not perfectly put in the it's place and goes skewed, the development is far from even. Actually negative could have even large area that is undeveloped! :eek:

So now I am returning to my original 'peg' implementation, which allows negative to move. The only fear is that could negative slip away from it's place when pouring off developer, stop or fixer?

Does the original pegs lock the negative to it's place or does them allow some lateral movement for the negative?

12-Jan-2009, 03:47
The clicking sound of lateral movement lets you know that the film is not stuck to the bottom of the tray.

12-Jan-2009, 07:12
The clicking sound of lateral movement lets you know that the film is not stuck to the bottom of the tray.

Thanks! I will soon test with my previous version of "pegs" :)

17-Jan-2009, 13:02

Now my "pegs" works fine. Got really good results.

But. Now after I have run calibration tests and developed several sheets, I found a problem. With the motor.

In my Orbital, the motor stops very easily, ie. if I just put my fingers to the rotating red 'thing' at head of the axle (see attachment), it will stop. The motor itself does not stop, it runs but somewhere inside the motored base (probably inside the lowering gears) something allows stopping of the main axle.

Same happens ofcourse if I put the developing tank on it's place. This hasn't happened before. Today was first time and since that, it just stops when I attach developing tank to the motor base - or just apply some pressure to the red 'rotator'.

This could be safety thing also, so I don't know how strong should the motor be.
Can you stop the red 'rotator' from rotating easily by hand?

If so, then my Orbital's motored base has only some problems with friction caused by that red thing at the top of the base (see attachment).
The red 'rotator' can be lifted of, so I will try to put some grease, silicon etc under it and test whether it has enough power to rotate whole orbital or not.

17-Jan-2009, 15:17
...Can you stop the red 'rotator' from rotating easily by hand?...

No. I fixed mine by opening it up and tweaking the gears.

17-Jan-2009, 23:57
No. I fixed mine by opening it up and tweaking the gears.

I opened the motor base and found out that gearing is bit worn.
Have to tweak them.

27-May-2009, 23:31
No. I fixed mine by opening it up and tweaking the gears.

How did you open the base? I couldn't find any screws holding the assemble together. I would like to get inside and possibly reduce the gearing further (slow up rotational speed).

Thanks in advance.


28-May-2009, 02:43
How did you open the base? I couldn't find any screws holding the assemble together. I would like to get inside and possibly reduce the gearing further (slow up rotational speed).
Thanks in advance.
The dome is snap-on. No screws (like 'no user servicable parts inside'). There are four barely visable lugs inside the bottom edge. Using a wooden wedge, release the lugs, starting from the slightly more flexible cable side. I used a clothes-peg. A screwdriver will break the plastic. When you are through, the dome snaps back into place with some pressure. The gears sometimes need re-seating. To reduce speed I'd rather use a rheostat on the line.

28-May-2009, 10:13
Bottom was hard to open, mine got one crack. But I does not matter.

I photographed whole procedure. If I have enough time, I'll put some photos on the net.

28-May-2009, 12:18
Thanks, I'll check it out, and use a clothes-pin to pry the side away from the bottom.

I tried a rheostat to reduce the speed, at 50% power the motor stalls and lurches. I want to either replace the gears, or the motor (maybe the motor, as the unit is now 240V and I want to convert to 110V).