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

[Andreas Thaler]

I'd hesitate to try writing a step by step tutorial because i'm still not convinced I did a good job yet.

You managed to take the camera apart, fix the problem and put it back together so that it works. That is an excellent achievement that I have not seen before with the Minolta 9000.

But on the other hand I know the threads where people have been looking for solutions to the aperture problem for many years.

Write the tutorial, it would be a blessing for everyone who wants to continue working with the 9000

 

[Andreas Thaler]

You managed to take the camera apart, fix the problem and put it back together so that it works. That is an excellent achievement that I have not seen before with the Minolta 9000.

But on the other hand I know the threads where people have been looking for solutions to the aperture problem for many years.

Write the tutorial, it would be a blessing for everyone who wants to continue working with the 9000

Where you are unsure, you could leave a note so that others can continue working on it.

I strongly vote for this project

 

[ogtronix]

I don't have it in me to write a whole tutorial but I was curious about whats involved in removing the mirror box without taking the top PCB off, as the service manual suggests to do it. Since i've got that other and more broken camera mostly together it'd be a chance to try see... and I figured i'd point out some of the things I remember giving me trouble during the first disassembly.

There's parts missing in this photo. To remove the top cover of the camera there's a screw hidden in the battery well of the hand grip. There's 2 other screws in there too, with the outer 2 being part of securing the shutter switch PCB to the hand grip. Only remove the middle one or some tiny parts can get loose early (the teal nut and the missing switch contact its holding down, which leaves the tiny pin the displeasingly yellow-green arrow is pointing towards).

The two power wires, with red arrows, need to be desoldered. Along with the the screw holding down that metal pressure plate marked blue plus the cyan nut and the not pictured switch contact under it, such that that top flex PCB can be pulled away from the green PCB below. After that there's 3 big screws on the side of the camera hidden under a plastic trim panel that can be peeled off, and then 2 more on the other side.

The rubber on all these old hand grips has rotted so it'll probably crack and peel off quite easily when there's less furniture to protect the delicate edges.

Under the handgrip is a plastic plate thats stuck on with some adhesive tape. I cracked the first one when trying to pull it off in one big go, and split it in half fully on this 2nd removal.

With the first camera a mystery washer dropped out at some point and I couldn't figure out where it went. On the 2nd camera it'd been stuck down with adhesive to prevent it moving. Without it the battery holder is fairly tight in the grip.

Silver pressure plate on the right is removed. I'm making some of these part names up because I can't remember what the service manual calls them.

All of the wires on this side should be desoldered. There's a grey wire under the lens release button and some of those PCB layers that can be desoldered too.

The final black wire down the right hand side of the camera can be desoldered from the bottom here. Or on the top PCB, but it's attached with a 2nd wire up there and it's fiddly to try get both reconnected at the same time. To remove the top PCB entirely I think those have to come off anyways though.

Also this green PCB should be removed entirely from the camera. It connects to the autofocus motor with 3 flat flex connections that are a bit annoying to desolder.

Some detail of the front mirror box screws, since they're almost all different from each other. The silver one is hidden under that flat flex PCB that can be lifted after removing the pressure plate. That stack of PCBs kinda pop over a silver peg they'll probably be snagged on, so some prying tools directly under the peg will help release them. Only the top one needs to be lifted at this point, but the 2nd one should also be released from that peg so it doesn't snag or something later. The bottom layer can stay in place.

I might try get some kind of magnetic pad to put under these sheets of paper so the screws dont roll around as easily before getting taped down.

Under the tripod socket is a green flex PCB that has to be lifted from 2 pads of adhesive. The 4 screws from the tripod socket themselves are pretty firmly held in, with retaining compound I guess, so a well fitting screwdriver tip and/or a bit of pressure on the screwdriver to try stop it camming out is a good idea.

This one lever in the charging mechanism should be removed. I didn't the first time and was able to get the mirror box out with some jiggling... but it has to be removed for reassembly anyways. It's awkward to get out and even more awkward to get back in since it has to be positioned right to engage the charging lever on the mirror box.

Some devious screws around the prism hold the mirror box in. The little eyepiece shutter assembly removes quite easily with the two smaller inner screws.

Under that trim/ light blocking piece are a couple of screws holding the viewfinder LCD down to the mirror box, so that has to be removed. It's held on with double sided tape and peels off fairly easily, but it's made out of a thin mysterious metal that can bend quite easily... but it can be bent back into shape if it's not too mangled.

 

[ogtronix]

These photos came out a little dramatic since I had the exposure compensation down a bit by mistake along with a sodium lamp.

Desoldering these connections sucks. I've tried use solder braid in the past to remove the solder entirely and what I find happens is just enough remains to still keep the parts stuck - but now there's no thermal mass for the solder to stay molten, or to help you conduct heat into the joints, and then you spend so long trying to warm it or pressing the iron tip in to get more contact that the flex PCB starts to delaminate... it seems to go alot easier when sliding a prying tool between the layers and gradually re-melting the joints in turn as things come loose bit by bit. Although the risk there is for blobs of solder to get flung off and end up places they shouldn't be.

There's a 2nd soldered flat flex connector on this same flank of PCB, at the bottom. That one is way narrower and easier to damage so make sure it's removed too.

3 screws with the red arrows here also mount to the mirror box and need to be removed. Theres a screw labelled with a blue arrow in the top right that's holding on the top PCB through the ISO button's tab, that i'm pointing out cuz there's a thin yellow washer in that stack to take note of since it'll get loose. It sits between the PCB and the metal tab of the tactile switch.

Final pressure plate connecting 2 flat PCBs together, hidden under the LCD assembly.

And a screw in the film compartment holding the shutter on. This probably doesn't need to be removed at this stage but who knows.

The flat flex of the autofocus motor needs to be tucked in or it snags on the body and risks being damaged. It's a little annoying since it likes to pop back into place as you're wiggling stuff trying to get the mirror box loose and making sure there's not still a secret screw or cable still attached. For re-assembly i held it down with some tape but it's harder to reach the tape into that hole on disassembly.

So! I was able to remove the mirror box like this by kinda pivoting it down and pulling it. But it didn't feel good... I think the flat flex connector under the LCD assembly might've been getting caught on something, but it also felt like there was a little bit of bending of the whole top PCB. Trying to get it to go back in wasnt too smooth with a whole bundred wires and cables to try prevent getting snagged and trapped in the wrong places...

I think removing the top PCB entirely is maybe more time consuming but it felt generally more... delicate. Like there's less chance of breaking or tearing stuff (although these old 80s electronics can be quite static sensitive i've heard, so a wrist strap might be a good idea if it's coming entirely off the body).

Cleaning the electromagnets. A bit of paper dipped in isopropanol and then put between the magnet faces and pulled out. Repeated a few times while being careful to not contaminate the cleaning part of the paper with hand oils since it'd be annoying to get it back together and have the problem persist.

And again, i'm still not 100% sure this is the cause of the problem. I only got the single camera working again (and possibly only temporarily) and it could be a fluke... but it seems plausible since i've read that other issues this camera can have are the mirror not moving and the aperture always closing down to minimum. All of which could be explained by one of each electomagnet sticking. Another thing that may have done something was spending a bit cocking the assembly and triggering the electromagnets with a bench power supply set between 2 and 4 volts while trying to figure out how it worked.

For re-assembly I think the service manual has alot of good steps. The first set of pages with exploded diagrams and part numbers is somewhat baffling (I really don't like exploded diagrams; they're hard to read!) but starting at page 68 of the scanned version on archive.org there's a whole section on step-by-step assembly of each... assembly. The bad scan makes some arrows hard to follow so i've enhanced a couple useful diagrams using highly sophisticated computer technology. Chances are if you buy a service manual from the many sites offering them for sale, or guys on ebay, you'd just end up with a printout of this same exact scan.

Also, if you do remove the top PCB, the hardest part to reassemble I felt was getting part 3428 of the "[8] Counter base plate" back in place. The manual doesn't cover that particularly well since you kinda have to get one side hooked in and then rotate the thing around. But even then it's like alot of fiddling till it suddenly just goes in as if there was never a problem to begin with.

Also the counter dial behaves differen't depending on if the film door is closed or not.

Also on the film door latch side of the camera you can access the latch with a prying tool to open the film door if you manage to close it with the rewind crank removed.

Also the assembly under the frame counter comes off easily with just 2 points to desolder, but there's a brass post under it that can get loose and escape to watch out for.


But yeah hopefully that covers the worst of disassembling these cameras. Andreas' posts cover how to remove the outer furniture, although i'd suggest removing the round thing under the rewind crank first before prying off the plate with "Average, Spot, H, S" since it gives access to lift it on a side that won't be visible if you gouge it.

 

[Andreas Thaler]

Great, that helps!

Thank you very much!

 

[ogtronix]

Bit of an update, the problem has started to resurface already! And the very day I got around to actually putting film in it. The delay was from trying to get ahold of a working motor winder and wanting the camera empty to test them when they arrived.

I guess at some point i'll have to disassemble it again and take another look. I could maybe swap the magnet in from the other camera and hope that just works, but I am curious about what the problem really could be. Again the 3 things I can imagine are:

1) The magnet surfaces get contaminated and sticky with migrating oil, condensed residues, or maybe something the magnet is constructed from degrading and leaking out.

2) The permanent magnet got stronger with time. I'm not convinced by this one but I think I read it somewhere.

3) The electronics have drifted with age and aren't delivering as much current to release it.

The first one is still the most plausible to me - the magnet getting stronger seems silly - and the third one could be possible... I should see if brand new batteries make a difference since I did spend 2 weeks playing with the autofocus and checking if the aperture still worked. Of course it's working fine again now that i've already probably ruined a roll and a quarter of film. Intermittent problems!

But yeah assuming the first thing is the problem then would I want to try deep clean/ immerse the magnets in solvent after fully removing them, or maybe slightly abrade/ etch the surfaces so they're not getting wrung together as easily?

 

[Andreas Thaler]

Bit of an update, the problem has started to resurface already! And the very day I got around to actually putting film in it. The delay was from trying to get ahold of a working motor winder and wanting the camera empty to test them when they arrived.

I guess at some point i'll have to disassemble it again and take another look. I could maybe swap the magnet in from the other camera and hope that just works, but I am curious about what the problem really could be. Again the 3 things I can imagine are:

1) The magnet surfaces get contaminated and sticky with migrating oil, condensed residues, or maybe something the magnet is constructed from degrading and leaking out.

2) The permanent magnet got stronger with time. I'm not convinced by this one but I think I read it somewhere.

3) The electronics have drifted with age and aren't delivering as much current to release it.

The first one is still the most plausible to me - the magnet getting stronger seems silly - and the third one could be possible...

I also believe that it is a problem with contamination, see

Canon T90: Cleaning the mirror magnet

I have a T90 here whose mirror magnet no longer works. The usual symptom of a quiet clicking sound and a flashing arrow in the display occurs. The recommended cure of removing the front cover and activating the - easily accessible - magnet with a magnetized screwdriver tip works with patience...

www.photrio.com

Excellent work, congratulations!

 

[Andreas Thaler]

@ogtronix

Since you have successfully removed and reinstalled the mirror box on the Minolta 9000, what do you think of these instructions (red markings) in the service manual for the 9000?

I read it as if adjustments are still necessary here that only Minolta could do.

Does the DIY work then make any sense at all?

On the other hand, if we want to solve problems such as faulty aperture control or a sticky shutter, we have no choice; we cannot do it without disassembling it.

What do you think?

 

[Andreas Thaler]

By the way, I think the service manual for the Minolta 9000 (your reference to the link to archive.org) is exemplary in terms of the presentation of information and instructions.

Everything is clear and can be understood without training, details are explained and not only the disassembly but also the assembly of components is described. This is the first time I've seen this here.

I should have read the service manual more closely before starting my project.

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

 

[Andreas Thaler]

I am thinking about this in relation to my current project:

Thread '8 x Minolta/Maxxum 9000 and 4 x Minolta AF lenses: a sample'
https://www.photrio.com/forum/threa...00-and-4-x-minolta-af-lenses-a-sample.210960/

The aperture controls on the six 9000s work, but I first need to check whether the shutters are working correctly. There was slight sticky dirt on the rear shutter curtain of two 9000s.

It could be that the frequently described problem with grease/rotting damper is occurring here.

In order to clean this, the mirror box and shutter will probably have to be removed.

 

[Andreas Thaler]

Dirk Münchgesang shows, among other things, dirt on the shutter of the 9000 here (I had already mentioned his contribution on APHOG which is in German):

Minolta 9000: Wiederbelebung bei typischen Fehlern und kleine Verbesserung der Kamera - APHOG – Analoge Photo Gruppe

Die Minolta 9000 hat einige bekannte Baustellen die gehäuft auftreten: Kamera löst nicht mehr aus wg. verschmiertem Verschluss Blende schließt nicht (bei anderen Minolta AFs auch ein bekannter Fehler) Darüber hinaus habe ich hier eine 9000, die fehlerhaft arbeitet (kein Bulb, Programmwählrad...

www.aphog.com

I'm now taking a closer look at it with my disassembled 9000.

I'm also looking at how you can check the shutter with the back panel removed, as there is a pre-release at 1/4000 second.

 

[forest bagger]

Hello Andreas!

On the other hand, if we want to solve problems such as faulty aperture control or a sticky shutter, we have no choice; we cannot do it without disassembling it.
What do you think?

I fix DSLRs since 2010 and am aware of the advices told me by Nikon service manuals like "adjust everything adjustable after reassembling a camera which had to be disassembled for repair" what usually only Nikon service points are able to.
In spite of these advices I do no adjusting at all - I only work deliberately an carefully. My customers were and still are satisfied with my work.

 

[Andreas Thaler]

Dirk Münchgesang shows, among other things, dirt on the shutter of the 9000 here (I had already mentioned his contribution on APHOG which is in German):

Minolta 9000: Wiederbelebung bei typischen Fehlern und kleine Verbesserung der Kamera - APHOG – Analoge Photo Gruppe

Die Minolta 9000 hat einige bekannte Baustellen die gehäuft auftreten: Kamera löst nicht mehr aus wg. verschmiertem Verschluss Blende schließt nicht (bei anderen Minolta AFs auch ein bekannter Fehler) Darüber hinaus habe ich hier eine 9000, die fehlerhaft arbeitet (kein Bulb, Programmwählrad...

www.aphog.com

I'm now taking a closer look at it with my disassembled 9000.

See

Minolta 9000: Examination of the sticky shutter and discussing solutions

Following these threads on issues with the Minolta 9000 https://www.photrio.com/forum/threads/minolta-maxxum-9000-dissection-and-investigating-the-aperture-issue.208476/ https://www.photrio.com/forum/threads/8-x-minolta-maxxum-9000-and-4-x-minolta-af-lenses-a-sample.210960/ I am starting a...

www.photrio.com

 

[Andreas Thaler]

Hello Andreas!
I fix DSLRs since 2010 and am aware of the advices told me by Nikon service manuals like "adjust everything adjustable after reassembling a camera which had to be disassembled for repair" what usually only Nikon service points are able to.
In spite of these advices I do no adjusting at all - I only work deliberately an carefully. My customers were and still are satisfied with my work.

With the Minolta 9000, you would have to find out what could possibly be misaligned by disassembling it.

I can only compare it with the Nikon F4, where the mirror box (integrated in the front part) can be removed, according to Larry Lyells in an issue of the SPT Journal. The settings for the AF are stored in a module under the mirror box and are therefore not changed. And in fact, the two F4s on which I did this perfectly work after reassembly.

But you have no choice anyway, if you want to solve problems in the 9000, you have to take it apart.

 

[ogtronix]

@ogtronix

Since you have successfully removed and reinstalled the mirror box on the Minolta 9000, what do you think of these instructions (red markings) in the service manual for the 9000?


View attachment 386386

View attachment 386387


I read it as if adjustments are still necessary here that only Minolta could do.

Does the DIY work then make any sense at all?

On the other hand, if we want to solve problems such as faulty aperture control or a sticky shutter, we have no choice; we cannot do it without disassembling it.

What do you think?

Yeah I figure that stuff means it involves special fixtures, gauges, and electronic/ computerized testing devices that wont exist outside of a Minolta service center and were either scrapped or in need of service themselves by this point. The pages it points to includes stuff like some I/O tester for the exposure and AF measurements, along with various charts and attachments.

But I also figure to an extent that's gotta be about adjusting stuff to a high and specifically defined tolerance so multiple bodies match each other. For barely-working garbage enthusiasts, it's probably not too big of a deal if the metering area is a bit misaligned and a third of a stop under.


The autofocus stuff looks somewhat complicated, and this is all speculation based on guessing and having ruined alot of cameras:

The MZ adjusting that seems to involve shim washers with the mirror box removed. Doubt this could be done DIY without but I doubt it'd need to be done unless the camera has a big dent in it. The manual suggests it's only needed if replacing the mirror box or the PCB that includes the autofocus CCD.

The AF area I assume just adjusts the mirror rest to get the autofocus CCD aligned with the box on the matte screen, and with an easy to reach screw (but requiring a weird tiny spanner) could probably be adjusted just aiming at the edge of something till it seems right.

The pitch and yaw adjustment screws seem easy to reach, even with it mounted to a bracket. I figure they're about getting the CCD parallel to the image plane, and if yaw is the long-axis of the CCD adjustment then you could maybe make that adjustment aiming the camera at a vertical line on a flat evenly lit wall at extreme ends of the autofocus range till it seems happy to focus on it. Then pitch would probably just increase the apparent contrast between the top and bottom linear CCD for better autofocus performance... maybe that could be adjusted by dimming the lights till it can just barely autofocus and seeing if you can get it to work better, and repeating.

EZ adjusting is done with a potentiometer hidden under a panel in the film compartment, and i've gotta assume this sets the focal distance. Seems very easy to just fiddle with and the most likely place to start since the electronics probably drift faster than the mechanics. I figure it'd be best not to touch any of the above stuff at all if it's not needed.


Page 26 (97 in the big PDF) covers body back adjusting which I kinda glossed over at first thinking it needed specialist tooling - but looking at it now it's just using a regular depth gauge, a flat enough block resting on the film plane, and shim washers under the lens mount to get the flange to focal distance correct.

The finder adjustment on the next page requires a potentially custom made wrench, VB adjuster, but it looks like the kinda thing you could make with a file out of brass. I doubt it's high torqe so it'd only need to bridge 2 flats on the hex nut.

That "Adjusting" after installing external parts is kinda vague. I guess it's suggesting adjustments have to be made since it's likely removing and reinstalling the mirror box might have misaligned things.


But yeah there's no other option than DIY with these, I feel. With the melting shutter bumpers a mirror box removal is gonna be something ever harder to avoid having to do. The bodies don't really have the professional history and cred of the various Nikon F's, or the well laid out if drab familiarity of anything Canon EOS, to have me imagining they'd ever be valuable outside of their novelty and style. Especially when lacking autfocus performance and having quite alot of frustrating UI shortcomings with the accessories that undermine their usefulness. And if doing professional repairs or reselling them with a warranty, I think more research is required to guarentee a long lasting repair.

All of which is to say, I think they're still for weirdos that want to mess around with stuff more than actually take photos. Or for people that like the idea of a system camera you can assemble into a horrible 3.6kg tech fractal for no good reason. But who knows; like with most old tech things they're only a big youtube video away from quadrupling in price. You'd be better off speculating in dog races than old cameas but it might make them worth more professional repairs if it happened. Until then I shall continue to mangle them.

 

[Andreas Thaler]

Yeah I figure that stuff means it involves special fixtures, gauges, and electronic/ computerized testing devices that wont exist outside of a Minolta service center and were either scrapped or in need of service themselves by this point. The pages it points to includes stuff like some I/O tester for the exposure and AF measurements, along with various charts and attachments.

But I also figure to an extent that's gotta be about adjusting stuff to a high and specifically defined tolerance so multiple bodies match each other. For barely-working garbage enthusiasts, it's probably not too big of a deal if the metering area is a bit misaligned and a third of a stop under.


The autofocus stuff looks somewhat complicated, and this is all speculation based on guessing and having ruined alot of cameras:

The MZ adjusting that seems to involve shim washers with the mirror box removed. Doubt this could be done DIY without but I doubt it'd need to be done unless the camera has a big dent in it. The manual suggests it's only needed if replacing the mirror box or the PCB that includes the autofocus CCD.

The AF area I assume just adjusts the mirror rest to get the autofocus CCD aligned with the box on the matte screen, and with an easy to reach screw (but requiring a weird tiny spanner) could probably be adjusted just aiming at the edge of something till it seems right.

The pitch and yaw adjustment screws seem easy to reach, even with it mounted to a bracket. I figure they're about getting the CCD parallel to the image plane, and if yaw is the long-axis of the CCD adjustment then you could maybe make that adjustment aiming the camera at a vertical line on a flat evenly lit wall at extreme ends of the autofocus range till it seems happy to focus on it. Then pitch would probably just increase the apparent contrast between the top and bottom linear CCD for better autofocus performance... maybe that could be adjusted by dimming the lights till it can just barely autofocus and seeing if you can get it to work better, and repeating.

EZ adjusting is done with a potentiometer hidden under a panel in the film compartment, and i've gotta assume this sets the focal distance. Seems very easy to just fiddle with and the most likely place to start since the electronics probably drift faster than the mechanics. I figure it'd be best not to touch any of the above stuff at all if it's not needed.


Page 26 (97 in the big PDF) covers body back adjusting which I kinda glossed over at first thinking it needed specialist tooling - but looking at it now it's just using a regular depth gauge, a flat enough block resting on the film plane, and shim washers under the lens mount to get the flange to focal distance correct.

The finder adjustment on the next page requires a potentially custom made wrench, VB adjuster, but it looks like the kinda thing you could make with a file out of brass. I doubt it's high torqe so it'd only need to bridge 2 flats on the hex nut.

That "Adjusting" after installing external parts is kinda vague. I guess it's suggesting adjustments have to be made since it's likely removing and reinstalling the mirror box might have misaligned things.


But yeah there's no other option than DIY with these, I feel. With the melting shutter bumpers a mirror box removal is gonna be something ever harder to avoid having to do. The bodies don't really have the professional history and cred of the various Nikon F's, or the well laid out if drab familiarity of anything Canon EOS, to have me imagining they'd ever be valuable outside of their novelty and style. Especially when lacking autfocus performance and having quite alot of frustrating UI shortcomings with the accessories that undermine their usefulness. And if doing professional repairs or reselling them with a warranty, I think more research is required to guarentee a long lasting repair.

View attachment 386423
All of which is to say, I think they're still for weirdos that want to mess around with stuff more than actually take photos. Or for people that like the idea of a system camera you can assemble into a horrible 3.6kg tech fractal for no good reason. But who knows; like with most old tech things they're only a big youtube video away from quadrupling in price. You'd be better off speculating in dog races than old cameas but it might make them worth more professional repairs if it happened. Until then I shall continue to mangle them.

Terrific!

I hope you stay active here with your well-founded contributions!

 

[ogtronix]

Terrific!

I hope you stay active here with your well-founded contributions!

Thanks! I'm on a multi-year on and off quest for a reliable camera with a particular job in mind, but i've been cursed to only find broken or dying ones it seems, or ones with quirks that make them unsuitable. Although at this point i'm also just buying cheaper broken ones on purpose most the time since I've had no luck with stuff sold as working, even from reputable places. I've got a dynax 7 somewhere in the post that has several things wrong with it, but there's been alot of investigation into those common faults since I last looked at them... so here's hoping.

As for the 9000AF's aperture problem, I did play with the assembly from the spare one a few days ago. Was considering if it'd be a good idea to entirely remove the magnet to clean it more thoroughly, since i'm not sure how it might've gotten recontaminated so fast if that is the problem, but i'm not sure it would be a good idea to remove it since it might be hard to get it back in aligned.

Maybe the thing to do would be to solder in some wires to make oscilloscope measurements of the pulses the camera sends to the magnets. I'd be curious if a stronger pulse might help release an uncleaned magnet... and if so i'd then wonder if you could put some kinda amplifier/ level shifter in somewhere. I've got an entirely unfounded assumption that the camera would be generating the mildest pulse possible to save on battery life or prevent overheating with prolonged use. The connection for all the problem electromagnets is 9 contacts of the "FPC gold plated pads pushed together" variety, under the LCD assembly. You can get flexible printed circuit stuff made pretty cheap now, so if that actually worked you could probably produce a drop in double-sided FPC for the middle of that stack.

Oh speaking of the LCD I also tried putting the bleeding one between some rubber sheets gently clamped in a vice for a couple days, and it did push out most of the air. I then tried sealing the edges with GS hypo cement after reading about that on a watch forum, but it kinda gooped out and got on the contacts. But it has me wondering if you could make inserts or produce a whole new LCD housing that puts more pressure on the LCD to try keep air out that way. Minimum orders for getting new LCDs made would be over §1000.

Not sure if i'm gonna continue messing with the 9000AF for a bit, but it's the kinda thing i'll return to cuz it'll haunt me as unfinished business otherwise. I enjoy messing with this stuff, but I still need to figure out a working and suitable camera so I can try make progress with other things.

 

[Andreas Thaler]

Thanks! I'm on a multi-year on and off quest for a reliable camera with a particular job in mind, but i've been cursed to only find broken or dying ones it seems, or ones with quirks that make them unsuitable. Although at this point i'm also just buying cheaper broken ones on purpose most the time since I've had no luck with stuff sold as working, even from reputable places. I've got a dynax 7 somewhere in the post that has several things wrong with it, but there's been alot of investigation into those common faults since I last looked at them... so here's hoping.

As for the 9000AF's aperture problem, I did play with the assembly from the spare one a few days ago. Was considering if it'd be a good idea to entirely remove the magnet to clean it more thoroughly, since i'm not sure how it might've gotten recontaminated so fast if that is the problem, but i'm not sure it would be a good idea to remove it since it might be hard to get it back in aligned.

Maybe the thing to do would be to solder in some wires to make oscilloscope measurements of the pulses the camera sends to the magnets. I'd be curious if a stronger pulse might help release an uncleaned magnet... and if so i'd then wonder if you could put some kinda amplifier/ level shifter in somewhere. I've got an entirely unfounded assumption that the camera would be generating the mildest pulse possible to save on battery life or prevent overheating with prolonged use. The connection for all the problem electromagnets is 9 contacts of the "FPC gold plated pads pushed together" variety, under the LCD assembly. You can get flexible printed circuit stuff made pretty cheap now, so if that actually worked you could probably produce a drop in double-sided FPC for the middle of that stack.

Oh speaking of the LCD I also tried putting the bleeding one between some rubber sheets gently clamped in a vice for a couple days, and it did push out most of the air. I then tried sealing the edges with GS hypo cement after reading about that on a watch forum, but it kinda gooped out and got on the contacts. But it has me wondering if you could make inserts or produce a whole new LCD housing that puts more pressure on the LCD to try keep air out that way. Minimum orders for getting new LCDs made would be over §1000.

Not sure if i'm gonna continue messing with the 9000AF for a bit, but it's the kinda thing i'll return to cuz it'll haunt me as unfinished business otherwise. I enjoy messing with this stuff, but I still need to figure out a working and suitable camera so I can try make progress with other things.

I will try to write a tutorial on removing the mirror box of the 9000, based on the work you have presented here. Of course I have first to achieve it myself, but I am optimistic now after reading the service manual. This makes it possible to access the known problems such as the rotting damper in the shutter and the defective aperture control.

I got lost when dismantling my 9000 after removing the top cover and then gave up.

Everything that is publicly documented about repair attempts, not just the successes, helps others and contributes to ensuring that the stars of yesterday can live on.

There is definitely interest in the 9000, this thread has had around 3000 views since August. That should also include access from the web via search engines. And I haven't found anything comparable on the web on this topic so far.

 

[Andreas Thaler]

As for the 9000AF's aperture problem, I did play with the assembly from the spare one a few days ago. Was considering if it'd be a good idea to entirely remove the magnet to clean it more thoroughly, since i'm not sure how it might've gotten recontaminated so fast if that is the problem, but i'm not sure it would be a good idea to remove it since it might be hard to get it back in aligned.

- The drive for the lens aperture adjustment no longer moves because the lubricant in the complex mechanism becomes resinous when not in use. Here, too, the camera must be almost completely dismantled.

Minolta 9000

(Google Translate German -> English)


Maybe everything there should be cleaned and sparingly oiled?

I don't know what all is involved in the aperture control and what it looks like, but you could use isopropyl alcohol or benzine (be careful with plastics) to rinse the moving parts?

Full quote:

The camera has a few design weaknesses that become apparent over the decades:
- The "rubber coating" loses its softness and becomes hard, brittle and crumbly. It usually falls off in larger or smaller pieces.
- The shutter has a damper or something similar made of a substance that has since turned into a greasy mass and sticks the shutter blades together. Unfortunately, the material used is quite stubborn, and attempts to clean it with benzine or brake cleaner are futile. This mass can only be partially removed with industrial alcohol, and the camera must be almost completely dismantled for complete cleaning. The damper does not seem to have been installed in all cameras, but there are numerous reports of "shutter stuck".
- The drive for the lens aperture adjustment no longer moves because the lubricant in the complex mechanism becomes resinous when not in use. Here, too, the camera must be almost completely dismantled.
- The LCD display on the top of the camera turns black at the edges because the liquid in the display gradually dries out.
- General electronic problems due to corroding connections of the many flexible circuit boards inside the camera or the contacts of switching elements, e.g. the mode dial.

 

[Andreas Thaler]

@ogtronix

Do you know Dirk Münchgesang's report on the dissection and examination of a 9000 on APHOG?

Minolta 9000: Wiederbelebung bei typischen Fehlern und kleine Verbesserung der Kamera - APHOG – Analoge Photo Gruppe

Die Minolta 9000 hat einige bekannte Baustellen die gehäuft auftreten: Kamera löst nicht mehr aus wg. verschmiertem Verschluss Blende schließt nicht (bei anderen Minolta AFs auch ein bekannter Fehler) Darüber hinaus habe ich hier eine 9000, die fehlerhaft arbeitet (kein Bulb, Programmwählrad...

www-aphog-com.translate.goog

(Google Translate German -> English)

Aperture does not close (also a known error with other Minolta AFs)

So the possible causes are sticky magnets and/or the mechanical area around the white lever, which actually controls the aperture position. Or just the electrical transmission paths via the gold foil contacts that are disrupted by dirt.

However, dismantling the entire […] section would be quite difficult and would not provide much further information. There are also too many springs and levers.

This is just a part of the detailed report on the aperture control problem.

 

[Andreas Thaler]

As long as the problem with the aperture control of the 9000 is not solved, the only option left is to keep several 9000s as reserves that do not have this problem. I have six with working aperture controls, which I see as an indication that not all 9000s are affected (yet).

The issues with the sticky shutter and the blurred viewfinder image seem to be manageable. The disintegrating plastic leatherette is mainly a cosmetic problem.

 

[ogtronix]

That confused me for a bit since "mechanical area around the white lever" had me at first thinking the problem was the sear here with the red arrow pointing to it.

Since it kept slipping out. But that's because I hadn't yet found the page in the service telling you how to properly charge it all for testing. And to repeat myself from earlier - that spring the blue arrow is pointing to had come loose in the 1st of these mechanisms I looked at, and was adding to the confusion since it didn't always engage.

The only corroded contacts I saw were from leaking batteries, but it's probably worth cleaning any gold contacts on reassembly anyways just in case you get fingerprints on them.

It didn't feel like there were any problems with a lack of lubrication, but that could be different in cameras that've lived in different environments. I gave up trying to repair a B200 a few months ago that was almost glued solid from cigarette smoke. The 2 9000AF mechanisms I played with were quite free moving and I always worry with trying to re-oil things that I might add too much or the wrong kind...

I think if the problem was the wider mechanism sticking then i'd expect to be able to hear the electromagnet disengage when pushing down the DoF preview... then maybe get things to start moving by shaking and tapping the camera without pushing the preview lever down the whole way to reset it. Which i'd like to test right now but the thing is now working flawlessly again after sitting on a shelf for a week, go figure. Maybe temperature is affecting things... gonna leave it in the garage for a few hours to see what happens.

 

[Andreas Thaler]

One possibility would be to disassemble a 9000 with an intact aperture control and compare the two mechanisms side by side. Perhaps this will provide some conclusions.

 

[ogtronix]

Totally bungled the Dynax 7 repair attempt yesterday so I celebrated by losing E-clips from the spare 9000's aperture mechanism.

I think if there's gonna be any dried oil stiction problem it'd be on that pivot for the electromagnet since it's a spring carefully balanced against the holding force of the magnet. Everything after that is all big springs and sears with less to get stuck. But at least on this one it doesn't look like it was ever oiled. There's a groove in the middle of the pin and I didn't notice any residue in it. I think for this application, something that sits still for a long while then suddenly has to move a short distance, just brass against steel would work better than anything oiled. But I suppose if you have the mechanism out of the camera then it wouldn't hurt to at least try cleaning it anyways. Plus its alot easier to reach the magnet's surfaces with this arm off.

The surfaces of that part which contact the magnet directly are a little shiny (I dunno what you'd actually call that part... the anvil?), like they've gotten polished or peened over the years. Maybe the idea of gently abrading the surface back to a matte finish with 800 grit paper or such, to prevent wringing like with gauge blocks, wouldn't be bad either. I can't imagine that'd hurt anything at least, I wouldn't touch the magnet itself, and it'd help remove another possibility for why the thing sticks.

That reminds me that one of the things that kills clockwork is the edges of pivot holes wearing into a better fit with their pins and increasing friction till things sieze. The relief groove in the middle of the pivot pin in this mechanism that is probably for friction reduction. It's possible wear there could be contributing to the problem... but probably not.

I think there'd be more to learn from a broken mechansim than a working one. But my intact 9000AF continues to work again during the one time I'd want it not to... If you've got a broken one on hand Andreas could you try pressing the aperture release thing down with your ear pressed against the camera, to try hear if there's any difference in sound from when the shutter is cocked vs uncocked? If there is a difference that could imply the problem is further down from the electromagnet.

 

[Andreas Thaler]

Andreas could you try pressing the aperture release thing down with your ear pressed against the camera, to try hear if there's any difference in sound from when the shutter is cocked vs uncocked? If there is a difference that could imply the problem is further down from the electromagnet.

Unfortunately, I don't have a 9000 with an aperture problem, which is crazy because I got rid of that exact category many years ago

I have one that is in mint condition, but the mirror is stuck and the shutter is blocked. Turning the motor coupling doesn't change anything. But this 9000 won't be suitable because the shutter doesn't work, and therefore also not the aperture control.