Minolta Dynax 7000i: Performance on the camera tester, defective shutter as a first repair project

[Andreas Thaler]

The Minolta (Maxxum) Dynax 7000i (Minolta Alpha 7700i) was the successor to the Minolta (Maxxum, Alpha) 7000 AF and was released in 1988.

The 7000 AF was the first SLR with integrated autofocus, which was a huge market success and ushered in the era of automatic focusing in SLR cameras.

The 7000i offers faster "intelligent" autofocus, multi-segment metering, and introduced the Minolta chip card system, which programmed the camera to expose specific subjects. For example, "Travel" with depth-of-field priority or "Portrait" with appropriate aperture priority for background resolution.

It's a heavy, solid and well made camera that can be acquired very inexpensively on the used market.

I just have managed to get three defective 7000i practically for free

I plan to open and examine one of them, following the instructions in the SPT Journal January/February 1991:

SPT Journal: January-February 1991

Society of Photo-Technologists Journal

learncamerarepair.com

A Minolta Service Manual seems not to be available.

I'm particularly interested in the extent to which the 7000i can still be DIY repaired and how the internals differ from the Minolta 7000.

I suspect that with the 7000i I am going to reach the limit of repairability, which I originally set with the Minolta 9000 AF. But I'm open to surprises.
I still also assume that it's not the integrated circuits that are failing, but the peripherals, i.e., contacts, connections and mechanical parts.

Here, too, we are breaking new ground, at least as far as repair reports on the web go. I haven't found anything on this except @ogtronix teardown at

Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut; LCDs, aperture ring, shutter unit replaced; aperture solenoid cleaned

There is always too little space on the table for such work 😌

www.photrio.com

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

One question though, these were also known for having leaking LCD windows. Can they not make these leak proof? This problem also affects The Nikon F4 as well and I had to stop using one because the LCD went blank after a few years in my use. With the F4 you can replace the LCDs quite easily...

www.photrio.com

I'm curious to see how the expedition goes

---

Minolta 7000i - Wikipedia

en.wikipedia.org

 

[Andreas Thaler]

I thought my knowledge of its predecessor, the Minolta 7000 AF, would give me a head start, but that's not the case.

While the 7000i has similar components and technologies, it's, of course, a new class of camera.

The electronics are more advanced, but there are still interesting connections with the mechanics that make DIY possible and interesting.

I need to prepare thoroughly for this project, which will take some time.

 

[Andreas Thaler]

A closer look

Since the 7000i is new to me, I took a closer look at both I own today, familiarized myself with how to use them, and put them on the Reveni Labs Camera Tester.

I am switching to the 7000i as a Minolta 7000 AF user.

While the 7000 AF features an amber illuminated viewfinder display, the 7000i boasts a bright green color plus an additional illumination for the main LCD. The viewfinder features LEDs for AF and flash.

As with the 7000 AF, the display is extensive on both LCDs.

A special feature are optional chip cards, which allow the 7000i's settings to be automatically optimized for specific subjects.

This card is the Portrait card, which favors large apertures.

The golden contacts still need a thorough cleaning, including those in the camera.

The card is inserted into the side flap …

… and can be switched on and off.

A revolutionary thing in 1988 that turned snappers into professionals and took work away from professionals - if they wanted it …


It turned out that one of the 7000i

has a problem with the shutter. The camera couldn't even build the medium shutter speeds, but otherwise everything worked fine.

Ideal for a first attempt at repair!


Candidate number two works perfectly

Here are the results on the camera tester for the shortest 1/4000 second.

The distance between the curtain travel times decreased after a few shots and thus also the exposure deviation in the image.

Apparently the camera hasn't been used for a long time.


Shutter test

The measurement is carried out using three sensors.

The camera tester offers four displays for a measurement result:

1/4000 s: Curtain travel times for the opening (C1) and closing (C2) shutter.

Above are the shutter speeds measured per sensor in milliseconds.

5.5 ms is the target curtains travel time following Larry Lyells in the SPT Journal. The result is close.

The shutter speeds shown as usual fractions, below the exposure deviation in the image shown as exposure value (EV).

You can see how the shutter curtains accelerate and decelerate. The exposure error is acceptable and decreases steadily toward longer shutter speeds.

Here the exposure deviation is displayed for the upper and lower sensors, while the measured shutter speed for the middle sensor is displayed in milliseconds. Below that, the curtain travel times.

In the first quadrant at the top left, the acceleration of the shutter curtains is shown in millimeters per millisecond.

Quadrants 2 to 4 show the opening and closing times of the shutter curtains per sensor. In the middle sensor, the first shutter curtain opens the slit after 1.91 ms, and the second shutter curtain closes it after 2.09 ms.

This gives an idea of the uniformity of the exposure slit as it speeds across the image.


Exposure test

Exposure test with a Minolta AF 50/1.7 lens attached at EV (exposure value) 15 and ISO 100.

The camera tester determines whether the 7000i sets a correct shutter speed/aperture combination for this brightness and at this assumed film speed.

It does, here in program mode. The target and actual values are identical, with no deviation in EV.

The diagram shows the exposure process.

The horizontal axis represents time, the vertical axis represents exposure.

It can be seen that the process is smooth.

What's going on with the tail on the right is interesting. The exposure should have already ended. I'm hoping the shutter isn't slowing down when closing.


Motor speed test

The camera tester can also determine the frame rate in continuous mode.

The 7000i manages 3 frames per second (FPS) with new batteries at 1/4000 s and AF disabled.

 

[Andreas Thaler]

Aperture test

The exposure test with a lens is only meaningful if the lens forms the apertures correctly. However, it's also helpful to know how the lens stops down.

My test candiate here is the Minolta AF 50/1.7 just used on the 7000i.

At full aperture, i.e., when the aperture blades are not visible, the measured aperture corresponds to the nominal value of the lens. Here, it is f = 1.7.

At the middle aperture of f = 5.6, this is no longer so nice; the lens only reaches f = 4.9, which means it overexposes.

However, the deviation is only small.

 

[Andreas Thaler]

Conclusion

• The camera tester gives a good idea of the camera's performance.
• Even if there are deviations, they aren't significant in practice with negative film.
• So, it wouldn't make sense to disassemble the 7000i or the 50/1.7 just to achieve getting minor better results.
• In the case of the first 7000i, however, the shutter isn't working, and I'll try to see if I can fix that.
• Overall, the 7000i is an impressive development of the 7000 AF. It feels great in the hand, is quiet, and gives a high-quality, solid impression. I'm curious to see what it looks like inside

+++

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

 

[forest bagger]

Hello Andreas,

I offer one item on ebay https://www.ebay.de/itm/145237524315 - and untill today no one wants to buy it.
Do you?

 

[Andreas Thaler]

Hello Andreas,

I offer one item on ebay https://www.ebay.de/itm/145237524315 - and untill today no one wants to buy it.
Do you?

Sold!

Why didn't anyone want the 7000i?

 

[Andreas Thaler]

Probably the usual „plastic camera“ verdict again.

I'll counter that with pictures when I open the camera and try to fix the shutter.

There's nothing cheap or inferior about it; the thing is solid and well-thought-out

 

[forest bagger]

Hello Andreas!

Why didn't anyone want the 7000i?

I don't know - maybe because the broken plastic on the grip?

 

[Andreas Thaler]

Hello Andreas!
I don't know - maybe because the broken plastic on the grip?

In the best case

 

[Andreas Thaler]

I almost forgot:

The 7000i has a red AF-assist illuminator on board. This allows the camera to focus in the dark and on monochrome surfaces by projecting a striped pattern for the AF.

This was previously only possible in combination with an external flash.

Yes, the 1980s were an exciting time in 35mm photography

 

[Andreas Thaler]

It turned out that one of the 7000i

has a problem with the shutter. The camera couldn't even build the medium shutter speeds, but otherwise everything worked fine.

Ideal for a first attempt at repair!

In the SPT Journal, Larry Lyells provides detailed troubleshooting information.

Regarding this error:

I suspect the magnet because the camera was used for a long time by the previous owner and it is unlikely that the solder joints will dissolve or the IC will become defective.

 

[Andreas Thaler]

Since I can't find the Minolta Service Manual for the 7000i, I'm using the one for the largely identical 8000i as a guide.

Unfortunately, this edition doesn't include instructions for removing the mirror box/shutter, nor does it have a troubleshooting section. The information in the SPT Journal is helpful here.

Minolta Maxxum 8000i Service Manual

Factory service manual

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