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:

1. three are OK,
2. three have the AF not in the target but can be focused manually,
3. and two are defective (shutter blocked or shutter curtain dented).

Of the two defective 9000s, I can use the handles on two and the back door on one to replace the others. Other parts can also be replaced, e.g. adjustment elements and base plate.

Two had slight smear marks on the rear shutter curtain.

The LCDs on all of them have leaked, but they can still be read.

The external condition ranges from very good to heavily used.










The plastic on the handle and back panel is a weak point; it has become brittle. A previous owner improvised here with adhesive tape, the other 9000 looks like this.

---

I will clean the six usable 9000s, replace parts and check them more closely.

Report follows.

I tried to correct the AF by cleaning the sensor and both mirrors in the mirror box, but that didn't work.

Here is an explanation for the problem:

Autofocus gives unsharp pics​

Provided that the picture isn't unsharp because of something common, such as too long shutter speeds leading to camera shake:

1. Check that the diopter adjustment dial is set for your vision. You can read more about adjusting this at another page on this site.
2. If the camera indicates that correct focus is found when the viewfinder picture is horribly blurred (and the resulting pictures are blurred, too), the focusing CCD may be misaligned. There are two solutions if this is the case; continue to take pictures focusing manually, or take the camera to a certified Minolta repair center.
3. If the pictures are correctly focused in the finder but blurry on film (or vice versa), the mirror actuators may be broken or the mirror itself misaligned in some way. This means that the camera must be serviced.

Click to expand...

These Minolta AF lenses also come from the box of defective/untested photo equipment:

• 2 x AF 35-70/4
• 1 x AF 35-105/3.5~4.5
• 1 x AF 70-210/4

All four have lame apertures, which I attribute to oil contamination; the 35-105 also has mold on two lenses.

I will try to fix this.

Statistics:

All of this together as a sample gives me an above-average susceptibility to errors.

The manufacturing quality of these first AF zooms is first-class, lots of metal, heavy. I'm curious to see what it looks like inside.

I have all four lens, never taken one apart. I will intrested in your findings.

I looked around on the web about the blurred image in the viewfinder.

There are indications of a misaligned mirror mechanism, but the AF would work correctly.

The practical test with film will show how the six candidates behave.

My goal is to get at least two 9000 with Motor Drive MD-90, battery holder BP-90 (12 x AA) and Program Back Super working.

The lens I prefer is the Minolta AF 28-135/4~4.5, which has an excellent rating on ARTAPHOT (German).

Overall, the 9000 is probably one of the most vulnerable SLRs, the fate of an otherwise excellent design over the decades.

You should be happy if you find functioning examples, although the majority of sellers are unlikely to know about the weak points.

However, you are at a disadvantage when it comes to problems with focusing, as this note in the Minolta Service Manual for the 9000 shows:

In the SO-FO (German) I found a reference to a possible missing support for the mirror.

This could explain the blurring in the viewfinder due to a misalignment, but this does not affect the AF:



This should be the position:




The author of the post describes a solution that helped him get the viewfinder image sharp again.

Otherwise, everything remains just speculation.

Even if I had the opportunity to identify deviations in the adjustment, it would still be unclear how I could correct them.

A look at the service manual shows that this plan must remain fiction for my DIY range

Andreas Thaler said:

View attachment 386289

These Minolta AF lenses also come from the box of defective/untested photo equipment:

• 2 x AF 35-70/4
• 1 x AF 35-105/3.5~4.5
• 1 x AF 70-210/4

All four have lame apertures, which I attribute to oil contamination; the 35-105 also has mold on two lenses.

I will try to fix this.

Click to expand...

I will start with the 35-70, here is a tutorial from Pete Ganzel:



For the 70-210:

Andreas Thaler said:

In the SO-FO (German) I found a reference to a possible missing support for the mirror.

This could explain the blurring in the viewfinder due to a misalignment, but this does not affect the AF:

9000 AF » Minolta 9000 AF - Sucher dejustiert?

So liebe Gemeinde - hier was zum puzzeln: Ich habe drei 9000 und heute ist mir erst folgendes Problem bei der einen aufgefallen: Unabhängig vom Objektiv

www.so-fo.de

This should be the position:

View attachment 386339


The author of the post describes a solution that helped him get the viewfinder image sharp again.

Click to expand...

The problem may actually be here and has been solved:

I had a problem with one of my 9000, in my case it was the bumper foam had deteriorated to point that the mirror would not seat, so it blurred at the bottom 1/3 but sharp on the top 2/3rds.

Paul Howell said:

I had a problem with one of my 9000, in my case it was the bumper foam had deteriorated to point that the mirror would not seat, so it blurred at the bottom 1/3 but sharp on the top 2/3rds.

Click to expand...

How did this affect the mirror? Was it dissembled by the impact?

I'm changing my story, got it mixed it up, taking the lens off my 9000 there is no foam. I checked my day book, it was the focusing screen that was not seating properly, Tempe Camera fixed the issue. Not sure which of my cameras had the the issue with the foam bumper, I need to go through my day books, might just be a false memory.

Paul Howell said:

I'm changing my story, got it mixed it up, taking the lens off my 9000 there is no foam. I checked my day book, it was the focusing screen that was not seating properly, Tempe Camera fixed the issue. which.. Not sure which of my cameras had the the issue with the foam bumper, I need to go though my day books, might just a false memory.

Click to expand...

Thanks for the info!

Recordings are worth it

Have you checked the focusing screen to make sure it is seated correctly.

Paul Howell said:

Have you checked the focusing screen to make sure it is seated correctly.

Click to expand...

Thanks, will check this.

Andreas Thaler said:

Two had slight smear marks on the rear shutter curtain.

Click to expand...

Insights:

Tomorrow we'll continue:

• Checking the shutters for functionality with the back panel open. All that is required is to close one contact mechanically.
• Measuring the shutter speeds with the Reveni Labs Camera Tester.
• Checking the focusing screens for correct installation (thanks for the tip to @Paul Howell) and options for adjusting the mirror.
• Cleaning
• Replacing parts
• Testing the six 9000s with film on the MD-90 motor with BP-90 battery compartment.
• Exploration of the Program Back Super 90, see https://www.photrio.com/forum/threads/minolta-9000-who-uses-a-program-back-super-90.210950/
• Developing films, scanning, assessing.
• Attempt to repair the lame apertures of the four Minolta AF lenses.

That will be a lot of work over the next few days

A second project will be the removal of the shutter of a 9000 for cleaning. I would like to make a tutorial for this, inspired by the work of @ogtronix.

But that will take some time, the tutorial for repairing the aperture control of the Nikon F4 is still pending.

Checking the shutter for functionality with the back door removed

As with other SLRs, the 9000 requires you to press a switch with the back door removed to allow the camera to set the shutter speed.

If you don't do this, the 9000 will stay at 1/4000 of a second. This is the automatically set shutter speed with the back door closed until the film is advanced to frame #1.

Since I have to operate the winding lever with my right hand, I have to use my left hand to operate the contact. Therefore, I have to stabilize the camera so that it doesn't slip.

Permanently fixing the contact with a device, such as a clamp, didn't work.




The Dremel vice is ideal for this purpose. With its soft plastic jaws, it holds the housing securely without scratching it.

Underneath is a slide light table that acts as a backlight so that you can observe the opening of the shutter.

The only thing that matters here is whether the shutter runs and the shutter speeds are formed plausibly in M mode (one issue with the 9000 is a sticky shutter as discussed).

The shutter speeds can then be checked precisely with the Reveni Lab Camera Tester.




Here is the switch, which is pressed in by a tab on the back door of the camera.






The wide side of the plastic spudger from iFixit lets you operate and hold the switch without the risk of scratching.




This allows the shutter to be cocked and released with the right hand as well as operate the slider for setting the shutter speeds.

After checking, everything looks good here.

All six passed the test.

The shutters function plausibly.

Checking the focusing screen for correct installation



To investigate the problem of partial blurring in the viewfinder (when focusing with AF/MF, the image is blurred, except for the lower area), I checked that the focusing screen was correctly seated.

To remove the focusing screen, a small tab above the screen must be pushed up, then the holder with the screen folds down.






The screen could not be removed from the holder. I thought the holder was bent, but there were two small adhesive strips holding the screen in place.

I don't think these are regular parts, they are not even and it would be new to me that focusing screens for changing are attached like this.

So I removed the adhesive strips and put the screen back in.

I was lucky, the screen has a grid pattern and so I could see in the viewfinder that all the lines appear sharp vertically and horizontally. From this I conclude that the focusing screen is correctly aligned.

Anyway these processes did not change the viewfinder image; the blurring was still present.


Trying to adjust the mirror with a piece of shrink tubing

In the above-mentioned post on SO-FO, the author reported that a small plate fell out of the mirror box of his 9000.

He looked for the original position of the plate and discovered an old glue spot on the underside of the mirror, which was on the edge. He then mounted a piece of shrink tubing over the mirror stop and after that the viewfinder image was sharp again.

(Google Translate, German -> English)

I tried that too.




Here also on my 9000 is a spot with old glue.




There is a spot on the mirror stop that is heavily worn.

I conclude from this that there was a damper attached to the spot with the adhesive that came off. From then on, the mirror fell onto the mirror stop without being dampened.






I attached a piece of shrink tubing loosely on the mirror stop.

But that made the viewfinder image even more blurry.

Anyway something had changed and I was on the right track.

So it was a matter of aligning the lower part of the mirror in terms of height. And a tilt also explains the partially blurred viewfinder image. In my case, the lower part of the mirror had to be lower.


Adjusting the mirror stop

The crucial clue came from a posting on photo.net, which I also mentioned earlier in the thread.

Here the author solved his problem with the mirror by adjusting the mirror stop. This is an eccentric with a hexagon screw.




Here again the picture from before showing the mirror stop.




For this screw Minolta shows a special adjustment tool in the service manual.




To adjust it, I used my small needle-nose pliers with curved ends.


To adjust the screw, the mirror must be folded up.

I see three ways to do this:






The one recommended by Minolta with one finger.

I used the spudger.




Set the shutter to the longest time of 30 seconds and release it.

You have both hands free and should let a clock run so that you can clear the mirror box in time and the mirror does not collide with the tool.




Set the bulb mode and hold the shutter button.

I coped well with that.




With a firm grip, the pliers no longer slipped off the screw and could be adjusted.




And indeed, the blur in the viewfinder disappeared after a few attempts and turning the screw clockwise, from left to right

So it is not a problem with the AF, because in this case the entire viewfinder image would be blurred and not just a part of it.

Adjusting the focus manually now also works, with the focus LED in the viewfinder helping.

I will see if everything works after exposing the test film.

A very positive interim result so far.

On this 9000

• the aperture control works,
• the shutter works
• and the viewfinder image is corrected.

Tomorrow I'll continue testing the shutter speeds with the Reveni Lab Camera Tester.

Then I'll clean and the 9000 can be put on the Motor Drive MD-90 with the battery holder BP-90. If everything works, I'll take it out for testing with film.

And finally I'll check whether the Program Back Super 90 cooperates with the camera.

Then I'll have the first set working


+++

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

Measuring the shutter speeds with the Reveni Labs Camera Tester





So that the camera can set the shutter speeds when measuring without a back door, I fix the switch contact on the camera with a jumper and adhesive tape.

It's not an elegant solution, but it works. And I finally have my hands free and no longer have to press the switch with the spudger.




You can see some of the sticky damper again on the front shutter curtain which I recently have cleaned.

I will probably have to clean this regularly until I am able to solve the problem by disassembling the 9000 and replacing the rotten damper. But the contamination is only light and should not affect the shutter's operation.