Minolta (Maxxum/Alpha) 9000 AF: Removal of the mirrorbox/assembly, investigating the aperture issue, replacing the sticky damper in the shutter unit

[Andreas Thaler]

The other thought is how i want to try stepwise document a 9000 repair. Could be fun to try do it on film with a digital backup.

Good idea!

I will also work on the 9000 soon: removing the mirror box, removing the sticky damper from the shutter and cleaning the aperture magnet.

I will report back on this.

 

[Andreas Thaler]

The abrasive grinder would produce a ton of fine abrasive dust you wouldn't want anywhere near the shutter mechanism. Plus aluminium is gummy and would probably clog the thing too. A burr or a saw might be a better fit... but still, I think opening it with screw removal is the easiest option. It's only the one spring you've got to worry about, and its not too bad.

Shutter unit of the Minolta 7000 AF


@ogtronix

I can't remember when I took the shutter of the 9000 apart.

Does the shutter on the 9000 look the same as the shutter on the 7000 in terms of the springs? See picture.

In other words, if I remove the cover over these springs, shouldn't the springs fall out?

 

[ogtronix]

In the 9000? I don't understand.

The 9000's shutter does have one spring that likes to come loose with the cover removed since it's sitting right on top (retained by one of the posts, and captive with the post going through a hole in the shutter cover).

 

[Andreas Thaler]

In the 9000? I don't understand.

The 9000's shutter does have one spring that likes to come loose with the cover removed since it's sitting right on top (retained by one of the posts, and captive with the post going through a hole in the shutter cover).

Thanks, got it!

 

[Andreas Thaler]

Removal of the mirror box, replacement damper in the shutter, cleaning the aperture magnet

The removal of the mirror box of the Minolta 9000 AF is described on page 120 (PDF) in the Minolta service manual. This includes a diagram of the cable connections on page 114 (PDF), which must be unsoldered. The assembly is also shown, with instructions for coupling the mechanism.

It is an exemplary representation that is easy to follow.

My aim is to prepare a 9000 for working with film.

Of the four known problems, three can be solved by removing the mirror box:

1. replacing the sticky damper in the shutter unit,
2. cleaning the contaminated aperture magnet which no longer separates reliably, and
3. removing a blockage in the mechanism (assumed).

Any adjustment of the mirror caused by a dissolved damper can be carried out from the outside, see

Minolta 9000: Checking shutter and focusing screen, adjusting the mirror, replacing parts, cleaning

In my inbox for defective/untested photo equipment there were still a few Minolta/Maxxum 9000s. Together with the others in the cupboard I now have eight of them. In terms of functionality - I quickly checked the AF, the aperture control and the shutter - the distribution is as follows: three...

www.photrio.com

I will report on the highlights; a tutorial should not be necessary due to the good documentation.

@ogtronix has already done the removal of the mirror box, repacement of the damper in the shutter unit and cleaning the aperture magnet, see his report in the thread.

So I am not reporting anything new here but maybe I can add in details.

Regarding the removal of the top cover see my report in this thread. This is the first step in removing the mirror box. See also pages 82 and 83 in the service manual.

We'll start soon, stay tuned!

 

[ogtronix]

Big fan of every other listing for a focusing screen looking like this.
View attachment 389196 View attachment 389198

Some day PM screen is gonna eventually show up and it'll be listed exactly like this, and then be directly wrapped in parcel tape for postage.

Ahahah... God damn it!!!

Now I gotta figure out how you clean these things. Any rubbing might cause scratches, so maybe dipping it in alcohol and then distilled water?

 

[forest bagger]

This looks like a finger print on the matted surface of the screen.
You need something that removes fat an dirt together like glass cleaner.
You can wipe very carefully with a very soft cotton swab, as long there is enough cleaning fluid on the surface.
Finally cleaning with distilled water is a good idea.

 

[ogtronix]

Yeah, that's what i'm thinking. Although starting with dish soap cuz the only glass cleaner i've got is straight up ammonia. I'll probably do a trial run on one of the many screens i've got that're already damaged. I'm scared to touch the surface at all since it might flatten out the tops of whatever texture is etched into it, and I think just being dipped and swirled in some variety of mild solvent will be enough to dissolve the finger grease off.

Mostly i'm pacing about about how to dry it without having dust get stuck and fused to the wet surface. I might order a filtered blower since it's something i've been considering for a while. Canned air duster could work but occasionally those things like to dispense a blast of liquid butane for no reason, which would instantly destroy this thing. But of course the problem with blowers is filtered or not you end up kicking up more dust and launching it in anyways with the venturi effect.

It's also in that "I could send it back..." realm but it's the only one of these i've seen show up.

 

[ogtronix]

Was starting to fuss too much, like to the point i'd be fine risking ruining it just so I can move on and not spend a week pacing about and feeling increasingly intimidated by the job.

Warm soapy water, warm tap water, and distilled water. I got real into slushees last summer and kept the cups for parts washing.

One of the things I was fussing about was how to hold it while swishing about. Holding it by the edges with gloves seemed like it'd be messy but it turns out the tweezers weren't quite enough. I got it out by putting gloves on and tipping the cup out to catch it, since reaching in to grab it might smush and scrape it against the bottom of the cup with some debris between. The 2 rinsing steps were done more carefully, only moving it vertically.

Drying was done aiming a blower at the center and pushing the droplets to the edges, which were tapped against a kimwipe to wick them away.

Alot cleaner. There's a bit of white dust on the left that's slightly out of focus, and the only thing I could see with the naked eye. I rinsed it again and tried blowing but it's stuck pretty firm and I'm best not risking trying to rub it off.

Always hard to take pictures of viewfinders. There's a few Dusts visible and a little bit damage at the top of the fame. But it's not much worse than any of the other focusing screens i've got.


My review of the Focusing Screen 70 PM: It's pretty alright. It works with 4.5 aperture lenses if your eye is in the right place, which is nice. I was worried it'd always be a shimmering black circle and make it annoying to use with any of the cheaper zoom lenses. Shame it's so rare though, and that at least the Pentax MX/LX screens don't really work as a replacement. Maybe a focusing screen designed for the autofocus era or DSLRs would work better.

 

[Andreas Thaler]

When manually focusing the first generation of Minolta AF lenses, you sometimes need a steadier hand than when repairing. The narrow focus ring without damping is a challenge

 

[ogtronix]

I like it for the reassurance it actually hit focus, and keeping track of I or the subject moved and it drifted. But I do have an M42 adapter and a couple of the usual Soviet M42 lenses to go with it.

Checking the flange focal distances, seems Minolta A is 44.5mm and Praktica M42 is 45.46mm. Unfortunate since the adapter is spacing it out about a millimetre, but I could always adjust the infinity point in the lens itself. I don't have any M42 mount cameras I imagine i'll want to use again any time soon. Man, looking at Pentacon Super prices again is reminding me how cheap the 9000 and its accessories are. Except maybe the SB-90S, but i'm not convinced those were real.

 

[Andreas Thaler]

I was able to find a printed service manual for the 9000 with perfect quality graphics, which is not the case with the available scan. So I will continue here.

The next project is to dismount the mirror box to remove the sticky damper in the shutter unit, then reassemble and take photos to get a documentation/tutorial.

Almost all of my 9000s are affected by this problem, the shutter no longer works properly because of the sticky residues. With the mirror box removed, the infamous aperture magnet can also be examined, which sometimes fails.

@ogtronix has already done that, I hope that I will be successful too.

We're starting soon!

 

[Andreas Thaler]

As far as I know, the Minolta service manual for the 9000 is the only technical documentation available for repairs.

Unlike the Minolta 7000 AF, for which there is also a separate edition of the SPT Journal and a C & C Associates troubleshooting guide.

Let's make the best of it.

However, the service manuals for the two AF Minoltas are written in an exemplary manner. There are detailed instructions, everything is clearly described, and among others the installation of the mirror box is also shown, which is a great help.

 

[Andreas Thaler]

Dismounting the mirror box, removing the sticky damper from the shutter unit

To get to the shutter, the mirror box has to be removed.

This is a long way with the 9000 AF, which also presents some challenges when desoldering parts. But the instructions for this are exemplary in the Minolta service manual and I managed it with almost no complications.

I was able to remove the sticky damper from the shutter unit without opening it. I will only know if this solution is successful once the 9000 is reassembled and working.

The connections between the mirror box and the housing are removed in many small steps. These include individual parts, assemblies, circuit board connections and cables.

In the service manual, the removal of the
mirror charge lever set is specified as a separate step. However, I was not able to get the lever out of the housing.

After loosening a part above it, I managed to remove the mirror box. Then the lever could also be removed.

Done after about four hours of work.

Mirror box, housing and shutter unit.

The shutter unit is attached to the housing with three screws. It can be removed after desoldering some cables.

 

[Andreas Thaler]

The damper, which has turned into a brownish, viscous and sticky mass.

Using a needle and a pointed probe, you can push and pull the stuff through the openings on the underside of the shutter frame.

This requires patience and the delicate shutter unit should not be put under any strain.

When I had removed the damper and could see no more residue, I rinsed the area with acetone.

From an earlier dissection, I knew that - apart from the damper - only metal was used here, which acetone could not harm.

Final external cleaning with isopropyl alcohol.

The result of the cleaning.


Subsequent cleaning of the slats/function without damper

With the shutter unit removed, I could only move the front shutter curtain a little. The rear curtain, which sits on the damper, remained hidden. I will try to remove sticky residue from the slats once the shutter can be cocked and released again after reassembly.

I also tried to loosen the screws on the shutter frame to get to the damper. But they were too tight and I stopped trying so as not to put any strain on the unit.

---

Note:

@ogtronix has managed to open successfully the shutter unit, clean it and install a replacement for the damper, see

Post in thread 'Minolta (Maxxum, Alpha) 9000 AF: Dissection, investigating the aperture issue, removal mirror box, sticky damper in the shutter unit'
https://www.photrio.com/forum/threa...amper-in-the-shutter-unit.208476/post-2850057

---

If everything goes well with the assembly, it will show whether the shutter works properly without replacing the damper. The rear shutter curtain is probably strained by the movement. The question is how this will affect it in the long term.

There is a long way to go. Only then will I know whether the cleansing measure was successful.

All that's left over from my time as a guitarist is the massive music rack with clamp lighting. Here in its new function as a holder for the service manual


+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

The sticky damper, fate of every Minolta 9000 AF with fatal consequences

I assume that this damper was built into the shutter unit of every 9000 AF. And therefore this problem potentially affects every 9000 today.

With the nine 9000s that I currently own, most of them show that in particular the short shutter speeds are no longer correct after several releases because the rear shutter curtain picks up residues of the sticky damper and then no longer runs correctly. This makes the camera unusable for taking photos.

This means that the shutter of every 9000 should be cleaned, which is not an attractive option given the effort involved.

But just cleaning the shutter blades is no use because they get dirty again straight away and the residues of the sticky damper are too big to get rid of that way.

 

[Andreas Thaler]

Notes on removing the mirror box of the 9000 AF

Here are some observations/conclusions:

• The Minolta service manual shows clearly what to do. It describes not only the removal, but also the assembly with graphics. This is not just service, it also shows how the shutter and mirror mechanism, which are separated, can be correctly recoupled.
• Before removing the mirror box, the tripod plate must be unscrewed so that the circuit board can be folded up as shown. This is not documented.
• Three soldered circuit board parts must be separated. This can be done easily with desoldering braid and lots of flux.
• In some cases, cables under the upper circuit board must be desoldered. For this it helps to fix this circuit board part with adhesive tape to make space. The flexible circuit board with conductor tracks can be bent, but must not be kinked.
• There are many screws and components when removing. As always, orderly storage and detailed photo documentation helps with assembly.
• Work should be carried out on an ESD work mat with grounding to protect the ICs from electrostatic discharge.
• The shutter unit is sensitive, see the instructions on how to handle it in the service manual.
• Replacing the shutter unit is pointless since they all might have a sticky damper by now.
• If I manage to assemble my 9000 AF, I will make a tutorial on how to remove the mirror box and shutter.

Minolta Maxxum Alpha Dynax 9000 Service Troubleshooting Manual : Minolta : Free Download, Borrow, and Streaming : Internet Archive

The service manual for the Minolta Alpha/Dynax/Maxxum 9000 (or A9000/α9000) film SLR.

archive.org

+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

Assembly of the 9000 AF: Close to success

Cleaning the shutter unit without disassembly: Success

The installation of the mirror box worked, I was able to get the 9000 in function.

Two problems arose:

1. The electronic mode dial for P, A, S and M as well as the slider for setting the shutter speeds on the top cover did not work.
2. The aperture ring in the bayonet was blocked.

Cleaning the shutter from the outside without disassembling it was successful. No further sticky residue from the damper got onto the slats.

I wanted to solve problem #1 by replacing the top cover. I suspected a defect on the circuit board with sliding contacts inside.

However, I then saw (#2) that the aperture ring was not rotating and was blocked. To investigate this, I would have had to disassemble the 9000 again.


Anyway, this mission was a partial success

I was able to disassemble and reassemble the 9000 and show that the sticky damper in the shutter can be removed from the outside without disassembly. This means that this sensitive unit is not exposed to any risk by opening it.

This 9000 is going to the spare parts.

In any case, there will be a new attempt, I still have a few 9000 AF in stock.

Since the sticky shutter seems to affect virtually every 9000 produced, it can be assumed that each needs this service, otherwise the camera cannot be used for taking photos. Incorrect exposures due to the disturbed shutter action are likely.

---

Here are some impressions of the assembly:

Shutter, mirror and aperture mechanism are tested for functionality before the mirror box is installed in the housing.

Cocking the shutter …

… and releasing.

Tension the aperture mechanism.

These elements are all tensioned before assembly.

Since I can tension the shutter while it is installed, it is also possible to check the two shutter curtains for dirt.

Here you can still see sticky residue from the rotten damper.

This residue can be removed using acetone and by moving the shutter curtains several times.

The mirror box is inserted into the housing. The service manual tells you how the various cables must be laid.

Make sure that all cables are in the right places and that nothing is crushed.

The 9000 AF is almost complete again, only the top cover and the upper adjustment elements are missing, as well as parts of the casing.

The camera can be tested for functionality without the top cover.

The aperture ring is blocked.

The shutter remains clean even after repeated firing. The sticky damper is completely removed.

When I tested the 9000, it showed no signs of life. I found advice in the service manual.

This small pin is pressed against a switch when the battery holder is inserted, which opens it. The circuit then receives power.

I didn't know where the pin came from before.

Here you can see the switch being pushed up by the pin and opening.

When disassembling, make sure that the pin is not overlooked and get lost. It sits loosely in an opening.

---

I spent most of the day putting this 9000 AF together.

Next time I can do it faster and focus more on the details.

I'll be back!


+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

Shutter cleaning on a Minolta Maxxum 9000 AF

Today I'm continuing with a Maxxum 9000, which is identical to the Minolta 9000 and Alpha 9000.

The camera was in a repair shop for inspection years ago, works perfectly and the shutter slats are clean. It looks like new.

So why am I opening this 9000?

Because I assume that every 9000 is affected by the sticky shutter by now, even if there are no sticky residues on the slats yet.

Let’s see if this is also the case with this Maxxum 9000.

---

Today, removing the mirror box went faster and I took the time to think carefully about each step and document key points such as separating solder connections and routing the cables with the camera. I followed the instructions for disassembly in the service manual again.

Here you can already see parts of the rotting damper in the lower part of the shutter unit.

To clean it, I remove the shutter unit. Three screws have to be loosened and five cables have to be desoldered.

Remnants of the damper have become stuck to the housing.

The decay is progressing.

According to the service manual, the mirror charge lever should be removed before lifting out the mirror box, which does not work.

Removing two plain bearings on the charge plate created some space, but the lever was still stuck. But as soon as the mirror box is carefully lifted, the lever can be removed.

A leisurely morning in Vienna

---

Next steps

I'll continue with cleaning the shutter from the outside, as described in the thread before.

This time I'll only tension the mirror mechanism and the aperture mechanism once before assembling them, but I won't test them.

Maybe the mechanics on the 9000 got messed up during the tests and the aperture ring got blocked because of that?

We'll see how it goes here.

I'll continue soon, stay tuned!


+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

Cleaning of the shutter unit

Using the pointed probe and a needle I was able to remove a good portion of the damper.

This time I not only rinsed with acetone, but also worked with the soft brush. This improved the result.

External cleaning with isopropyl alcohol.

The housing is also clean again.

Some sticky residue that came on the slats after taking out the rotten damper has been cleaned.

As I ran out of acetone, I worked with isopropyl alcohol, which leaves streaks. But that doesn't affect the function of the shutter.

Nevertheless, I will improve the appearance with acetone when I have refilled it.


And the assembly worked this time

I was also able to solve the problem with the non-functioning mode dial with slide switch.

As suspected, there were contact problems; you can see the two connections here.

When assembling the top cover, a screw goes in here, presses both together and then the contact works. I didn't think about it when testing with the cover on.

Mission accomplished

What still needs to be done is to adjust the mirror, which can be achieved using an eccentric in the mirror box. The cause for this is a missing damper to which the mirror was set.

This Maxxum 9000 AF should be ready for work again. Tomorrow I will test the shutter speeds.

What a day!

---

Conclusion

• Removing the mirror box, cleaning the shutter and reassembling it are all doable. The 9000 AF is complex but with the Minolta service manual, patience and care you can make good progress.
• A tutorial on this topic here on PHOTRIO is in the planning stages.
• If the aperture magnet stays in shape, this Maxxum should have a long photographic life.
• Whether the missing damper is a disadvantage remains to be seen in practice.
• Respect for the technology of the 9000 is okay, but it shouldn't stop you from taking action yourself when it comes to repairs

+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

Shortest shutter times off

The check on the Reveni Labs Camera Tester shows that the shutter speeds up to 1/1000 s are within the limits, the 1/2000 is sporadically formed with large deviations, the 1/4000 not at all.

I then rinsed the shutter curtains with acetone, which did not help, but greasy residues formed on the blades again. Obviously was cleaning from the outside not enough.

Or the 9000 cannot achieve the short shutter speeds without a damper.


Overall, my impression is that the shutter unit is the fate of the 9000.

If you leave it as it is, the times are not correct because of sticking, if you clean it from the outside, nothing will improve.

The only option left is to dismantle the shutter, clean and replace the damper, as @ogtronix did. It would be interesting to see what the shutter speeds look like here.

The solution at the time of production of the 9000 probably was to replace the shutter unit without attempting to repair it. Unfortunately, that is no longer possible today.

I will try it again with the shutter disassembled and cleaning in the near future, but I am not optimistic because any disturbing the unit will likely have an impact on the performance. At least that is what is stated in the service manual.

 

[Andreas Thaler]

ICT Camera shows the disassembly and cleaning of a vertical focal plane shutter (Copal?) for Nikon.

I will use the procedure shown for the shutter of the 9000, it is the same type.

I further assume that the problems with the shutter of the 9000 are due to the rotten damper.

 

[Andreas Thaler]

Just published, note for all who are new to the topic:

Minolta (Maxxum/Alpha) 9000 AF: Tutorial for removing the mirror box, notes on assembly

In order to access the shutter for repairs or replacement, the mirror box on the Minolta 9000 AF must be removed. The same applies to fixing problems with the aperture control or the mechanics of the mirror box. This tutorial provides information with direct reference to the Minolta Service...

www.photrio.com

 

[Andreas Thaler]

Removal and disassembly of the shutter unit, cleaning with acetone

Here is the Copal shutter, which I just have removed and had cleaned from the outside of its sticky damper (located on the bottom).

A pointed probe, needle, brush and acetone were able to remove almost all of the stuff, but enough remained to spread over the lamellae. There are also oily traces in the area of the bearings.

It's a miracle that the Copal still worked at all.

 

[Andreas Thaler]

Clearly, the attempt to clean the shutter from the outside was unsuccessful.

To clean it, the shutter has to be disassembled, which is not too difficult. However, it remains to be seen whether I will be able to insert the infamous top spring correctly when I reassemble it.

I will bathe the individual parts in acetone and then reassemble the shutter.