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

[Andreas Thaler]

Maybe this is a clue?

Post in thread 'Minolta (Maxxum) 9000: Dissection and investigating the aperture issue'
https://www.photrio.com/forum/threa...gating-the-aperture-issue.208476/post-2821192

 

[Andreas Thaler]

You have probably already seen page 184 in the Service Manual (PDF):

And of course page 10 in the PDF:

 

[Andreas Thaler]

View attachment 376671

View attachment 376678

View attachment 376679

The fold-out rewind crank is fixed by a retaining clip.


View attachment 376677

View attachment 376682

View attachment 376681

A retaining ring and a screw hold the rewind axle assembly with fork.


View attachment 376683

After disassembly.

Erratum

The rewind crank does not need to be disassembled to remove the top cover.

The entire unit can be pulled out upwards after removing the fork for the film cartridge.

 

[ogtronix]

You have probably already seen page 184 in the Service Manual (PDF):

View attachment 386747


And of course page 10 in the PDF:

View attachment 386746

Nice, the problem returned just long enough to see that F does indeed blink. I hadn't noticed that. It started working again before I could try listen for a click though.

I'd kinda skimmed the troubleshooting checklist part of the manual and missed that part. It's one of the first parts I tried read and I went cross-eyed with the suggested solution to every other problem being to replace a whole PCB. Going through that stuff in order:

A cracked solder joint seems like it would cause more of a total or randomly intermittent fault than the kind i'm experiencing where the camera seizes after sitting idle for a few days.

Same again with trying to reflow the contacts on IC1 and... I think 4? They appear to be the 2 ICs on the evil hard to reach side of the PCB that straddles the pentaprism, but I think removing that PCB anyways is the better way to disassemble the camera before removing the mirror box. Reflowing joints seems like a hassle and might just cause more problems... and it'd be surprising if such a common fault were all caused by the same solder joint partially failing.

Flex PCB-F is the one the magnets are on. I guess this just means the gold contacts pressed against each other, which'll probably get cleaned during reassembly.

SL2 is the green eletromagnet that catches and stops the mechanism after it's started moving. It's a normal-style electromagnet that's actively held while a current passes through it, and released when the current stops. If it's failing then the mechanism will instantly stop at max aperture - but you should be able to hear a click from SL1 releasing and the first stage of the mechanism moving, possibly similar or exactly the same to how it sounds running the DoF preview set to max aperture when it's functional... which is loud enough I feel I would've noticed it even without sticking the camera against my ear.

I think "aperture ring: off position" means the ring that connects to the aperture lever of the lens is binding. It's possible the thing could get bent in use or from an impact since it's exposed. If this is the problem then you'll hear the rest of the aperture control mechanism loudly clicking when activating the DoF preview, which I haven't been.

"Sector gear stop lever spring" must refer to this one, which seems to be in place with both of the mechanisms I have. Probably worth checking all the springs seem to be attached properly at both ends though since I did have another out of place.

If the ICs are defective then that'd be unfortunate. I'd assume it's not the problem though just becaus cleaning stuff did make my camera run a whole lot better than it used to, even if it's still intermittant.


Part 2 "no F blinks" is probably for failures where the aperture mechanism works enough to spin the encoder disc but not later stuff and I don't think they're likely part of the common aperture problem.


Guess I'm kinda assembling a big list of potential causes of the problem here... and i'm not sure if the good idea would be to just take a nuclear approach and try eliminate as many as possible when I psyche myself into attempting to disassemble things again... or if I should narrow down the next most probable cause, only repair that, and see if it fixes things. At this point I'm more interested in figuring the problem out than actually having a working camera.

 

[Andreas Thaler]

When looking at the troubleshooting charts in the service manuals, I get the impression that this is often a theoretical error or a manufacturing error.

The problems that only appear after decades of use and aging are of course not covered.

Since the aperture control is one of the common errors in the 9000, it will be a design error, but I do not know whether this error occurred during production.

The fact that an electronically controlled, highly complex SLR is still in use after 40 years will not have been part of the planning.

 

[ogtronix]

Finally caught it with the fault. I store it with the shutter unwound since I assume that's healthier for it. So after winding and pressing the DoF plunger down to the first stage, there's zero sounds from inside the camera. Pushing it all the way and repeating that a few times between, shaking the camera, tapping the camera, yelling at the camera, it continues to not actuate the aperture. But after firing the shutter once and re-cocking it, it then begins to work.

It feels like a clue though, the way the depth of field preview plunger doesn't clear the fault but firing the whole shutter does. I'll have to think about it...

And yeah this fault is so common now it's surprising it's not really addressed in the service manual. Alot of the faults listed there do feel theoretical - with the engineers preemptively imagining faults, what might cause them, and how you might fix them. Maybe it's just that particular manual though and later revisions might've addressed it. It's just hard to imagine it would've been unknown to Minolta since as a "professional SLR" I figure they'd have a long support life.

 

[Andreas Thaler]

@ogtronix

Here is a guide to fixing the similar/same (?) aperture problem on the Minolta 7000.

Maybe something can be derived from this for the 9000?

I fixed my Minolta 7000 (aperture magnet problem)

groups.google.com

 

[ogtronix]

That's my big plan when I quit stalling opening the 9000AF up again, to abrade the surface of the lever that sticks to the magnet. Along with some more cleaning.

 

[Andreas Thaler]

That's my big plan when I quit stalling opening the 9000AF up again, to abrade the surface of the lever that sticks to the magnet. Along with some more cleaning.

The mirror magnet on the Canon T90 is often inactive.

Cleaning all contact surfaces with electronic cleaner has always solved the problem permanently.

 

[ogtronix]

Woof, finally got around to opening it again. It took just under 2 hours to get the mirror box out, and now I need to take the kinda break that might last a day or two.

Also got one of them silicone anti-static mats. It makes it look like I know what i'm doing! Unfortunately I desoldered some wrong wires and made things more annoying when it comes to reassembly. I also must've torqued the hell out of some screws when reassembling it the last time and chewed a couple up trying to get them back out. I bought a JIS screwdriver set since my old cheap tipped Phillips set was... it actually worked pretty well, no camming problems, but the tips were starting to wear out. I guess my conclusion is that not all the screws in here are JIS, probably just the ones with the dot/ dots to indicate so, so that's something to watch out for.

 

[Andreas Thaler]

Woof, finally got around to opening it again. It took just under 2 hours to get the mirror box out, and now I need to take the kinda break that might last a day or two.

View attachment 388128

Also got one of them silicone anti-static mats. It makes it look like I know what i'm doing! Unfortunately I desoldered some wrong wires and made things more annoying when it comes to reassembly. I also must've torqued the hell out of some screws when reassembling it the last time and chewed a couple up trying to get them back out. I bought a JIS screwdriver set since my old cheap tipped Phillips set was... it actually worked pretty well, no camming problems, but the tips were starting to wear out. I guess my conclusion is that not all the screws in here are JIS, probably just the ones with the dot/ dots to indicate so, so that's something to watch out for.

Great!

The silicone mats are not grounded, or I can feel electrostatic charge, so I work with electronics on such mats:

BERNSTEIN ESD workplace with grounding mat for SMD/THT assembly, 5 pieces | ESD earthing materials at very favourable prices | reichelt elektronik

ESD workplace with grounding mat for SMD/THT assembly, 5 pieces ESD earthing materials by BERNSTEIN - Reliable delivery ✓ favourable prices ✓ For business and private ✓ Order online at reichelt elektronik now!

www.reichelt.com

The mat and an earthing bracelet are connected to earth in the mains power socket and are therefore at the same potential. Charges are equalized via a resistor.

I cannot say how mains is set up for each country, I only know it for Austria

These mats can also be used for soldering.

JIS screws can also be seen without a dot, and you can also loosen Phillips screws with a JIS screwdriver, but not the other way around.

 

[Andreas Thaler]

Regarding JIS:

JIS DRIVE

JDV Products, Inc. is VESSEL’s Exclusive USA Distributor for Air Nippers and Cutting Blades, and a direct importer of all Vessel items

www.vesseltools.com

Screwdrivers:

Photo equipment: Basics for getting started with DIY repairs

As others I enjoy to report on my repair efforts here, but maybe someone would like to get into the topic? The desire is there, but there is still a lack of information on how best to start, what tools are needed and how much it might cost? That can be easily clarified. But it is even more...

www.photrio.com

 

[ogtronix]

Great!

The silicone mats are not grounded, or I can feel electrostatic charge, so I work with electronics on such mats:

BERNSTEIN ESD workplace with grounding mat for SMD/THT assembly, 5 pieces | ESD earthing materials at very favourable prices | reichelt elektronik

ESD workplace with grounding mat for SMD/THT assembly, 5 pieces ESD earthing materials by BERNSTEIN - Reliable delivery ✓ favourable prices ✓ For business and private ✓ Order online at reichelt elektronik now!

www.reichelt.com

The mat and an earthing bracelet are connected to earth in the mains power socket and are therefore at the same potential. Charges are equalized via a resistor.

I cannot say how mains is set up for each country, I only know it for Austria

These mats can also be used for soldering,

JIS screws can also be seen without a dot, and you can also loosen Phillips screws with a JIS screwdriver, but not the other way around.

The one I purchased claims to be conductive and a couple reviews were corroborating that, but I don't have anything to test it here myself I don't think. It was an order of magnitude cheaper than a real one and it's not like there's a shortage of factories trying to make more moulded silicone garbage than there's any demand for. I grounded the mat to my PC's case since that ended up being convenient, via a case screw... and my ankle is grounded to the soldiering station since that was convenient (there's a hole in the desk from an old monitor arm). Wonder if there's a reason to not ground yourself via the ankle. The usual wrist grounding puts you at risk of the iconic "sweeping a wire across the desk and yanking everything off" move.

 

[Andreas Thaler]

The usual wrist grounding puts you at risk of the iconic "sweeping a wire across the desk and yanking everything off" move.

I hate the bracelet with its spiral cord. It's always in the way and that's probably why I often forget to put it on …

 

[ogtronix]

Regarding JIS:

JIS DRIVE

JDV Products, Inc. is VESSEL’s Exclusive USA Distributor for Air Nippers and Cutting Blades, and a direct importer of all Vessel items

www.vesseltools.com

Screwdrivers:

Photo equipment: Basics for getting started with DIY repairs

As others I enjoy to report on my repair efforts here, but maybe someone would like to get into the topic? The desire is there, but there is still a lack of information on how best to start, what tools are needed and how much it might cost? That can be easily clarified. But it is even more...

www.photrio.com

I got one of them Vessel sets and I like it, but i've found if the screw requires more torque than can be comfortably applied with the thin knurled shaft/ the rubber bit then they're at real risk of camming out in a way the cheap and tipped set i've got doesn't. It might be less about how it fits and more that it's just easier to feel what's happening when you're not squeezing the driver as hard as you can.

 

[ogtronix]

I hate the bracelet with its spiral cord. It's always in the way and that's probably why I often forget to put it on …

I think I remember reading years ago that the pro move is just to keep your elbows/ forearms on the table and in contact with the mat.

 

[Andreas Thaler]

I think I remember reading years ago that the pro move is just to keep your elbows/ forearms on the table and in contact with the mat.

I wouldn't rely on that.

 

[ogtronix]

I'm taking another break after spending a bit playing with the aperture mechanism again. Here's a before and after of cleaning, hitting it with everything i've got from Pepsi to a pencil eraser.

This is also a 2nd attempt cleaning, the first one was by pinching a piece of alcohol soaked paper between both faces and pulling it out several times - so it must've looked even worse untouched. It's quite alot of residue if it'd just wicked in or settled from the atmosphere. I'd bet it's some sort of degrading lacquer.

 

[Andreas Thaler]

I'm taking another break after spending a bit playing with the aperture mechanism again. Here's a before and after of cleaning, hitting it with everything i've got from Pepsi to a pencil eraser.

View attachment 388248 View attachment 388249

View attachment 388250 View attachment 388251

This is also a 2nd attempt cleaning, the first one was by pinching a piece of alcohol soaked paper between both faces and pulling it out several times - so it must've looked even worse untouched. It's quite alot of residue if it'd just wicked in or settled from the atmosphere. I'd bet it's some sort of degrading lacquer.

Would it hurt to polish the surfaces, e.g. with a Dremel?

 

[ogtronix]

Would it hurt to polish the surfaces, e.g. with a Dremel?

No real need to, the parts are so tiny you can get the same effect by hand and with less risk of it grabbing the part and launching it.

I got the thing back together but with 2 new exciting problems. One is the camera not recognizing when it's switched to manual focus and the other is the finder LCD missing segments. Guess i'll open it up and check continuity and stuff tomorrow, but probably all that jostling on the LCD's cable shifted it a bit and it could do with re-seating. Aperture seems to work though but we'll see.

The times it took to reassemble it was 3 hours.

 

[ogtronix]

The focus thing was just that the switch contacts needed cleaning. Maybe flux vapours condensed on it when re-attaching the wire.

The finder LCD is causing some issues though. I think even if I massaged it back to having all segments conducting again it'd still be a bump away from losing it again. Page 69 (hueheh) in the repair manual covers that repair but specifies a 0.5mm thick elastic connector. I assume that means one of them zebra strips but I dunno where i'd get one that thin. Also turns out B-30 is specified later in the manual as just "Araldite" so probably epoxy.

Either way, you can get Z-Axis Conductive Tape these days so I might try source a small amount of that in the UK. A roll of the stuff costs over £300 but those maker hacker type stores sell small sections. E: Ordered some from the Netherlands. Guess it'll take a week or so.

 

[Andreas Thaler]

The focus thing was just that the switch contacts needed cleaning. Maybe flux vapours condensed on it when re-attaching the wire.

The finder LCD is causing some issues though. I think even if I massaged it back to having all segments conducting again it'd still be a bump away from losing it again. Page 69 (hueheh) in the repair manual covers that repair but specifies a 0.5mm thick elastic connector. I assume that means one of them zebra strips but I dunno where i'd get one that thin. Also turns out B-30 is specified later in the manual as just "Araldite" so probably epoxy.

Either way, you can get Z-Axis Conductive Tape these days so I might try source a small amount of that in the UK. A roll of the stuff costs over £300 but those maker hacker type stores sell small sections. E: Ordered some from the Netherlands. Guess it'll take a week or so.

Sometimes I ask myself why we torture ourselves with such projects.

It tires the eyes, causes back pain, isolates you from family and friends, haunts you in your dreams and never ends.

For that very reason: good luck!

As soon as I can dismantle the 9000 properly, I'll join in!

 

[ogtronix]

I think i'm mostly motivated out of spite and obsession after one bad experience, like a batman villain. The bad experience was having a particular project in mind a few years ago, one I still want to do, that'd require a reliable SLR I could trust with several weeks worth of carefully arranged exposures... and it turned out that was a big ask. I went through a bunch of SLRs from various manufacturers and eras while trying to set it up - figuring out why each one sucked and wouldn't work for a unique and frustrating reason. So many of them are already compromised for the sake of creating a mid-range, or designed to only function as intended with official accessories... Then the few cameras that aren't are overpriced and unreliable anyways. The 9000 is sorta unique in that while it is absolutely unreliable, they're still not too expensive. I think that's entirely down to almost all the top LCDs looking ugly, since being just unreliable/ near death hasn't slowed the climbing prices of other cameras.

I got close to having a camera I could use with the 600si, but then the grip fell off and it got fussy about what batteries it'd accept. Maybe repairable but it had me considering other cameras with all it's annoyances like a useless half-stop only bracketing mode, no leader out film rewind, no focus confirmation beep or lights, and some other small things... Like if I were to put the effort in i'd probably want a Dynax 7 but then they're a little expensive to comfortably start taking to bits.

Er, but yeah. I just want a camera I can trust to not turn a month's work into blank frames and light leaks. Which is a foolish desire that's led to a bit of an obsession. Which isn't to say I don't enjoy this crap it's just if I could i'd happily spend money at this point to just move on... but I've had a 100% failure rate buying things from actual camera stores listed as working and/or "CLA'd," and for considerably more you'd pay on eBay for 'untested' stuff... but at least they tend to accept returns.

 

[Andreas Thaler]

Yes, obsession is part of it.

I am a user and collector and I suffered from not being able to help my photo patients in the closet when something wasn't working, even small things. The repair shops made a good living from it.

Until I took action myself.

And now I can't get away from it

 

[BMbikerider]

I would love to work on something like this but my engineering and repair skills are with much larger pieces of equipment. If it doesn't involve torque wrenches or an assortment of spanners from 10mm to 26mm I am struggling.

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.