Minolta (Maxxum/Alpha) 7000 AF: Recommendations and notes, extended technical details for DIY repairs

[Andreas Thaler]

Based on my repair experience with the Minolta 7000 AF with regard to typical issues and repair options, I would like to give a summary of my findings and solutions.

All listed problems can be solved with relatively little effort.

---

The camera always forms the smallest aperture in all modes, regardless of the aperture value set

Aperture magnet that does not separate due to contamination.

Two possible solutions:

1. Regular repair (long way): remove the mirror box and clean the magnet.
2. Shortcut (short way): remove the covers, make a hole in the magnet cover from the outside, separate the magnet with a probe or needle and clean it with isopropyl alcohol or electronic cleaner.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

You can only test the full functionality of a camera after it has been completely assembled. If something goes wrong along the way, you might not notice it straight away. Then you have to take it apart again and look for the fault. With the 7000, this is a complex game with the many soldering...

www.photrio.com

The camera always forms the largest aperture, regardless of the aperture value set

The aperture ring is blocked, possibly jumped out of one or more of its rollers. Remove the bayonet and reattach it.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

I'm not really sure why LCDs never seem to be connected with the gold contacts directly against to the ITO traces. Regular stiff PCBs won't be flat enough and you'd be stressing the glass to try press them together, so it makes sense to use something flexible there. But here maybe the conductive...

www.photrio.com

Viewfinder LCD no longer shows all or any digits

Remove top cover, disassemble display unit, clean contacts on circuit board and LCD with acetone (thanks to @ogtronix for the tip). Reassemble.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

Under „Aperture Malfunctions“ in the C & C guide there are instructions to unsolder the white cable to the aperture magnet and then trigger the shutter when the aperture is always open, the LCD displays are correct and the shutter speed is plausible. The aperture then either closes or it...

www.photrio.com

Viewfinder LCD is displayed with tilt

Remove the top cover and adjust the display unit using the two fastening screws.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

I'm not really sure why LCDs never seem to be connected with the gold contacts directly against to the ITO traces. Regular stiff PCBs won't be flat enough and you'd be stressing the glass to try press them together, so it makes sense to use something flexible there. But here maybe the conductive...

www.photrio.com

Main LCD on the top of the camera leaked (black spots)

Remove top cover, replace with intact LCD from a discontinued 7000.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

I'm not really sure why LCDs never seem to be connected with the gold contacts directly against to the ITO traces. Regular stiff PCBs won't be flat enough and you'd be stressing the glass to try press them together, so it makes sense to use something flexible there. But here maybe the conductive...

www.photrio.com

Post in thread 'Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled'
https://www.photrio.com/forum/threa...x-removed-and-reinstalled.211422/post-2867146


Dismantling and assembling the mirror box

Allows cleaning of the aperture magnet, replacement of the shutter, and repair of problems in the mirror and transport mechanism.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

With the Minolta/Maxxum/Alpha 7000 AF Minolta ushered in the autofocus era in 1985. Similar to the Minolta 9000 AF, the Minolta 7000 AF can have problems with the aperture control. No matter what aperture is set, the 7000 always creates the smallest aperture. I suspect that the contact...

www.photrio.com

No sticky shutter

Unlike its sister, the Minolta 9000 AF, the 7000 does not have a damper for the rear shutter curtain, which can decompose and stick the shutter blades.

Post in thread ‚Minolta (Maxxum/Alpha) 7000 AF: Aperture issues resolved/shortcut, viewfinder display replaced, main LCD exchanged, mirror box removed and reinstalled‘

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

I'm not really sure why LCDs never seem to be connected with the gold contacts directly against to the ITO traces. Regular stiff PCBs won't be flat enough and you'd be stressing the glass to try press them together, so it makes sense to use something flexible there. But here maybe the conductive...

www.photrio.com

Behavior of the aperture

After the camera is released and the aperture is closed and opened, the aperture closes again briefly to the smallest value on the Minolta AF lens. This is a normal function.

Minolta 7000: Behavior of the aperture

I have observed the following with my Minolta 7000 in M mode: aperture set to any value, shutter speed as well, camera triggered, aperture closes to the specified value, after the shutter speed has elapsed the aperture closes to the smallest value for a tiny moment and opens. Is this behavior...

www.photrio.com

Lithium backup battery

The original lithium backup battery for the camera settings should in many cases still provide sufficient voltage and not leak.

Thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...ed-plastic-cleaning-contacts-voltages.211223/


Protected against leaking batteries (AA and AAA)

Both battery holders (BS-70L for AA and BS-70S for AAA) do not damage the camera's battery contacts if the batteries leak due to the design of the 7000's battery compartment.

Post in thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...leaning-contacts-voltages.211223/post-2861424

Post in thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...leaning-contacts-voltages.211223/post-2861447

Post in thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...leaning-contacts-voltages.211223/post-2861799


Brittle plastic cover

on the handle and battery holder BH-70S can be removed or repaired with Sugru.

Post in thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...leaning-contacts-voltages.211223/post-2861452

Post in thread 'Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages'
https://www.photrio.com/forum/threa...leaning-contacts-voltages.211223/post-2862397

---

See also

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

With the Minolta/Maxxum/Alpha 7000 AF Minolta ushered in the autofocus era in 1985. Similar to the Minolta 9000 AF, the Minolta 7000 AF can have problems with the aperture control. No matter what aperture is set, the 7000 always creates the smallest aperture. I suspect that the contact...

www.photrio.com

Minolta 7000: Memory backup lithium battery, main batteries, functionality, 7000 or 9000, disintegrated plastic, cleaning contacts, voltages

Completely unexpectedly, my neighbor gave me an obviously unused Minolta 7000 with two equally new Minolta AF zooms, complemented by a Minolta Program 2800 AF flash, which works just like all the other devices. Sometimes things just come to you on their own 😌 Today I looked at the built-in 3...

www.photrio.com

The Minolta 7000 AF repair marathon

I was recently able to purchase a bundle of eight Minolta 7000 AF cameras that were advertised as defective at an extremely reasonable price. The cameras arrived today and have all been through a lot. From a cracked top cover and broken light inlet cover, a shredded shutter curtain or...

www.photrio.com

---

Ressources

SPT Journal 1997

Issue dedicated to the Minolta Maxxum 7000

learncamerarepair.com

Minolta Maxxum 7000 Service Manual

Factory service manual and SPT repair guide

learncamerarepair.com

There is an issue of the C & C Troubleshooting Manual for the Minolta 7000 AF, it is highly recommended.


+++

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

 

[Andreas Thaler]

Minolta (Maxxum/Alpha) 7000 AF: Tutorial for removing the mirror box and shutter unit

In order to access the shutter for repairs or replacement, the mirror box on the Minolta 7000 AF must be removed. The same applies to fixing problems with the aperture control or the mechanics of the mirror box. This tutorial shows the necessary steps. The basis for this is the Minolta Service...

www.photrio.com

 

[Andreas Thaler]

Mike Eckman has written a comprehensive review of the Minolta Maxxum 7000 AF, which, among other things, deals in detail with the topic of autofocus:

Minolta Maxxum 7000 (1985)

This is a Minolta Maxxum 7000, a 35mm SLR made by Minolta Camera Corp in Japan between the years 1985 and 1988. This version of the camera was sold for export

mikeeckman.com

 

[Andreas Thaler]

Minolta (Maxxum, Alpha) 7000 AF: Extended technical details for DIY repairs​

Since I can hardly find any repair reports on the Minolta 7000 AF on the web, I would like to add more information for DIY repairs to my previous repair threads here on PHOTRIO.

It will be about the electronic control, mechanical and construction details and the possibilities to find and fix errors.

My previous repair experience with the 7000 shows that this SLR is robust and has few typical weak points that can be managed.

A solid performer

The plastic used on the housing should not disguise the fact that the 7000 is made of solid metal in the key areas and can withstand stress.

The 7000 offers all the essential functions for 35mm photography and, together with the high-quality Minolta AF lens range and the large Minolta AF system, is an interesting SLR for a variety of applications.

The used prices are low, and the range is large due to the high production numbers. This means that spare parts are also available for repairs.

Reference sources and practical evaluation

I will work through the three reference sources for repair work

• Minolta Service Manual,
• SPT Journal and
• C & C Troubleshooting Guide (author of both publications: Larry Lyells)

and also present the repaired 7000 in practical use in hybrid photography.

Since I have already repaired several 7000s for this purpose, the success of the repairs can be determined directly. Photo motifs await in Vienna

I am looking forward to a longer journey together to a milestone in photography from the perspective of the DIY repairman!

I will merge this thread with

The Minolta 7000 AF repair marathon

I was recently able to purchase a bundle of eight Minolta 7000 AF cameras that were advertised as defective at an extremely reasonable price. The cameras arrived today and have all been through a lot. From a cracked top cover and broken light inlet cover, a shredded shutter curtain or...

www.photrio.com

This means that this thread here will deal with technical details and discussions, and the practical repair work will take place there (linking).

This will allow the reader to decide whether they want to find out more about the theory or the practical repair work.

 

[Andreas Thaler]

The Minolta 7000 AF autofocus system

The Minolta 7000 AF was the first SLR with an integrated autofocus system in 1985.

This sophisticated system essentially works like this:

• A small section of the image in the center (limited by the AF mark on the focusing screen) falls onto an auxiliary mirror via the semitransparent main mirror.
• A condenser collects the light and directs it onto another mirror in the base of the mirror box.
• This mirror reflects the light on two tiny lenses located in front of a CCD (charge-coupled device) sensor.
• Depending on whether the focus is in front of or behind the image plane, the two lenses project the image to the right or left of a focus plane.
• The sensor converts the light received into electrical charges that form a pattern and are digitized.
• The AF motor under the mirror box, in conjunction with the digital control of the 7000, executes the focusing of the lens based on the digital signals provided by the sensor.

The system is described in detail in the March 1985 issue of Popular Photography:

Minolta Maxxum 7000 (1985)

This is a Minolta Maxxum 7000, a 35mm SLR made by Minolta Camera Corp in Japan between the years 1985 and 1988. This version of the camera was sold for export

mikeeckman.com

(The image above also comes from there.)

The author is Norman Goldberg, who also wrote the reference work Camera Technology: The Dark Side of the Lens.

You will also find Information about the AF system in

SPT Journal 1997

Issue dedicated to the Minolta Maxxum 7000

learncamerarepair.com

Dissection: Excursion to the CCD sensor

I took a look at the structure of the CCD unit on a spare part 7000.

Separated mirror box, the arrow points to the CCD unit on the bottom.

The CCD unit is attached via springs with three adjustment screws.

On the left the AF motor.

Green arrow: opening to the CCD sensor.

White arrow: part of the prism of the flash receptor.

The auxiliary mirror, which is movably mounted under the mirror.

Opening in the main mirror.

Rubber cover plate removed from the bottom of the mirror box.

Screws, springs and washers of the CCD unit.

The CCD unit is now only connected to the flexible circuit board.

Separated with cut circuit board (as a dissection for our study purpose).

Further disassembly, the condenser is exposed.

Deflecting mirror that directs the light from the auxiliary mirror above to the two mini lenses in front of the sensor.

 

[Andreas Thaler]

Deflecting mirror removed.

Overview

The sensor (in the middle) is exposed and separated from the board.

The mini lenses in the middle of the housing which project two images onto the CCD sensor.

The sensor is part of an IC (IC7).

Close up of the sensor.


Flash receptor

With this sensor, the camera measures the light reflected from the film and switches off the flash when the amount of light is sufficient (TTL flash control).

The flash receptor in the bottom of the mirror box is connected with a double-core cable to …

… the circuit board above the prism.

 

[Andreas Thaler]

The fascinating thing about the AF system of the Minolta 7000 AF

is that it is not only sophisticated but completely integrated into the camera.

In 1985, twelve Minolta AF lenses were released together with the 7000, which are connected exclusively electronically with the camera's two microcomputers.

Important lens data is stored in a ROM (read-only memory) in the lens and is integrated into the program control.

This AF system appeared overnight and I remember how the photography world was turned upside down at the time. The competition had nothing comparable on the market.

A blockbuster that was offered at an affordable price which brought together the level of what was technically possible at the time in a beautifully designed housing.

The fresh and colorful marketing was no less impressive:

https://www.pacificrimcamera.com/rl/01831/01831.pdf

Last but not least:

What you learn here in terms of technology with the mother of all AF SLRs can be used to benefit your understanding of all subsequent AF SLRs

+++

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

 

[Andreas Thaler]

A secret revealed: Film-detecting switch SWSLS

The Minolta 7000 AF has several internal switches that connect the mechanics and electronics.

One of these is the SWSLS switch, which allows the 7000 to recognize when film is loaded and when it is rewound by the inbuilt motor.

This is not a switch with a button for human activation, but rather the combination of the film pressure roller (green arrow) and transport roller (blue arrow) made of conductive rubber forms the switch.

If no film is fed in, the switch closes. The film pressure roller and transport roller are in contact.

The resistance between the rollers can be measured with an ohmmeter. It is around 8 to 15 kiloohms. Current can flow here.

When film is drawn in, it lies between the film pressure roller and the transport roller. The film strip acts as an insulator and separates the contact.

The switch is open and the connection is high-resistance. No current can flow.

If the film is rewound after exposure and the last piece slides out between the rollers, the contact is closed again. The motor switches off.

This system allows the 7000 to recognize the different states and control them.

SWSLS. Film-detecting switch.
Closes when the metal film-guide
roller touches the conductive rubber
of the take-up spool. SW SLS
opens when the film comes between
the roller a n d the c o n d u c t i v e
rubber. Opening SW SLS enables
the film counter. When SW SLS
closes, the frame counter returns to
0 and MI shuts off to stop the
rewind (Ml shuts off 5 seconds
after SW SLS closes).

SPT Journal, Minolta Maxxum 7000 Service Manual, Winding-base Plate Set, issue 1987


+++

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

 

[Nimbus62]

Top quality...

Now have to do the same for XM....

 

[Andreas Thaler]

Top quality...

Now have to do the same for XM....

Thanks!

The question is which of the two Minoltas is more complex …

 

[Nimbus62]

XM is metal, mechanical body with and additional analogic electronic two control the second curtain.
7000 is plastic, some mechanical part with digital electronic... and with a lot of user selector.... Very different and certainly more difficult for 7000 (from my point of view).

To be comfortable with XM adjustment need a test bench for Finder with reference body and Finder test to adjust the body... I build also a bench for Finder to test them without opening them... Some works for rainy days...
I will publish some information in some weeks... (Have to translate from french...).

 

[Andreas Thaler]

I will publish some information in some weeks... (Have to translate from french...).

Excellent! Looking forward!

In order to avoid having to use my poor English, I let Google translate most from German to English. It's very quick and the results are excellent.

Copy, paste, edit, publish.

Maybe an option for you?

Google Translate

Google's service, offered free of charge, instantly translates words, phrases, and web pages between English and over 100 other languages.

translate.google.com

 

[Andreas Thaler]

View attachment 391994

View attachment 391984

Deflecting mirror removed.


View attachment 391995

View attachment 391996

Overview


View attachment 391993

The sensor (in the middle) is exposed and separated from the board.


View attachment 391987

View attachment 391991

The mini lenses in the middle of the housing which project two images onto the CCD sensor.


View attachment 391990

View attachment 391992

The sensor is part of an IC (IC7).


View attachment 391985

Close up of the sensor.


Flash receptor

With this sensor, the camera measures the light reflected from the film and switches off the flash when the amount of light is sufficient (TTL flash control).


View attachment 391988

View attachment 391986

View attachment 391989

The flash receptor in the bottom of the mirror box is connected with a double-core cable to …


View attachment 391997

… the circuit board above the prism.

The measuring cell for the TTL flash exposure control in the bottom of the mirror box. The prism is attached.