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

[ogtronix]

Reusing photos from way earlier...

Yeah removing that top panel gave access. The shutter blades are all riveted to their linkage arms and didn't seem super ready to jump out, but i'd still try be cautious about not moving them too much or tipping the shutter over with the cover removed. Also watch out for the lever to actually fire the shutter since it could be a mess if that tripped with the cover off.

A few big things come loose. There's a shim/ leaf thing on the left that comes out, there's the reinforcing panels on the outside of the shutter's cover that can come loose, and in that photo is a bit of white tape i'm fairly sure was from the spool of a roll of film and not original to the camera - there were a couple of torn sprocket holes in the body too.

The tricky part though is that spring on the right that comes loose. The longer leg rests against one of those posts (take note of which one before opening it. It looks like the lower of the 2nd post from the bottom but it's not super clear in the photo) and the hook attaches to the linkage arm. There might be a way to trap it and hold it still before removing the cover, like a blob of blu tack... although i'd worry about that fouling things or depositing unwanted oils. It's fiddly to reattach though.

The method that worked for me was to unhook the spring from the hole in the linkage, position the long arm around where it's supposed to go (on the outer edge of the post), put the cover back on after replacing the bumpers (a tiny bit of temporary tape helped keep that one shim/leaf thing in place), then trip the shutter since that moves the hole in the linkage down and to the right and closer to the edge for access. Then using whatever tiny hooks or tweezers you have available, try fish the spring's hook into it's hole. It took me a few tries since I kept accidentally flexing the top cover enough that the spring's long arm was able to escape over the top of the post it rests again. It was a real fiddle.

It's a shame they didn't just put a little notch in that post to catch the spring. But I guess the whole unit was never supposed to be opened like this.

 

[Andreas Thaler]

Reusing photos from way earlier...

View attachment 389101
Yeah removing that top panel gave access. The shutter blades are all riveted to their linkage arms and didn't seem super ready to jump out, but i'd still try be cautious about not moving them too much or tipping the shutter over with the cover removed. Also watch out for the lever to actually fire the shutter since it could be a mess if that tripped with the cover off.

A few big things come loose. There's a shim/ leaf thing on the left that comes out, there's the reinforcing panels on the outside of the shutter's cover that can come loose, and in that photo is a bit of white tape i'm fairly sure was from the spool of a roll of film and not original to the camera - there were a couple of torn sprocket holes in the body too.

The tricky part though is that spring on the right that comes loose. The longer leg rests against one of those posts (take note of which one before opening it. It looks like the lower of the 2nd post from the bottom but it's not super clear in the photo) and the hook attaches to the linkage arm. There might be a way to trap it and hold it still before removing the cover, like a blob of blu tack... although i'd worry about that fouling things or depositing unwanted oils. It's fiddly to reattach though.

The method that worked for me was to unhook the spring from the hole in the linkage, position the long arm around where it's supposed to go (on the outer edge of the post), put the cover back on after replacing the bumpers (a tiny bit of temporary tape helped keep that one shim/leaf thing in place), then trip the shutter since that moves the hole in the linkage down and to the right and closer to the edge for access. Then using whatever tiny hooks or tweezers you have available, try fish the spring's hook into it's hole. It took me a few tries since I kept accidentally flexing the top cover enough that the spring's long arm was able to escape over the top of the post it rests again. It was a real fiddle.

It's a shame they didn't just put a little notch in that post to catch the spring. But I guess the whole unit was never supposed to be opened like this.

Thanks!

The service manual lets you down on this topic:

I'm wondering if I should try to dissolve the damper with acetone without opening the shutter unit. Even if I can't replace the damper. Then I'll have one less problem. Maybe it will go through the two openings on the bottom.

But there's too much mass there and it will probably mess everything up. I can't clean the stuff out through the openings either.

 

[Andreas Thaler]

What if I try to bend the bottom edge down? It's not connected to the frame. Then I can remove the stuff and put in a replacement.

Brutal of course, but it saves having to open the unit.

 

[Andreas Thaler]

Apparently the shutter was only designed for complete replacement, not for repair.

 

[ogtronix]

View attachment 389104

What if I try to bend the bottom edge down? It's not connected to the frame. Then I can remove the stuff and put in a replacement.

Brutal of course, but it saves having to open the unit.

Most likely you'd just bend the whole thing.

 

[Andreas Thaler]

Most likely you'd just bend the whole thing.

I'm trying it on the shutter unit that I removed during a dissection.

 

[ogtronix]

Apparently the shutter was only designed for complete replacement, not for repair.

Wonder if there was some deal with Copal (I assume) supplying the shutters. Like if I was John Copal, the CEO of Copal, i'd not want to sell Minolta shutters knowing they're giving out instructions on how to repair them. I'd want them to buy whole new shutters.

 

[Andreas Thaler]

I'm trying it on the shutter unit that I removed during a dissection.

No chance, even if I can grab the frame directly.

 

[Andreas Thaler]

Wonder if there was some deal with Copal (I assume) supplying the shutters. Like if I was John Copal, the CEO of Copal, i'd not want to sell Minolta shutters knowing they're giving out instructions on how to repair them. I'd want them to buy whole new shutters.

Crazy people like us have to pay the price.

 

[Andreas Thaler]

Second attempt, you can forget about it.

 

[ogtronix]

Maybe you could saw or grind the tabs off? I assume that frame is made from aluminium so you don't gotta worry about magnetic debris. Then replace it with some kind of effed up carved or 3d printed block that holds the rubber bumpers, adhered in place but also secured by touching the frame of the camera (possibly being adhered down there too, with epoxy).

I think just opening it and replacing the bumpers with some ones cut to the same shape as the originals is the way to go... there's way less potential for damage.

 

[Andreas Thaler]

Maybe you could saw or grind the tabs off? I assume that frame is made from aluminium so you don't gotta worry about magnetic debris. Then replace it with some kind of effed up carved or 3d printed block that holds the rubber bumpers, adhered in place but also secured by touching the frame of the camera (possibly being adhered down there too, with epoxy).

View attachment 389108
I think just opening it and replacing the bumpers with some ones cut to the same shape as the originals is the way to go... there's way less potential for damage.

Yes, that's something for the Dremel! Maybe with the corundum grinder. I could then slide the replacement under the frame and glue it in.

I'd rather do anything than play around with the little springs in the shutter.

I think I have all the information now. I'll get back to you when I'm there.

Thanks again.

 

[Andreas Thaler]

Removing the shutter unit to get to the place with the damper should have been no problem, as far as I remember, three or four screws. But there was a coupling element that was in the way?

Never mind, I'll see about it.

 

[ogtronix]

The abrasive grinder would produce a ton of fine abrasive dust you wouldn't want anywhere near the shutter mechanism. Plus aluminium is gummy and would probably clog the thing too. A burr or a saw might be a better fit... but still, I think opening it with screw removal is the easiest option. It's only the one spring you've got to worry about, and its not too bad.

 

[Andreas Thaler]

The abrasive grinder would produce a ton of fine abrasive dust you wouldn't want anywhere near the shutter mechanism. Plus aluminium is gummy and would probably clog the thing too. A burr or a saw might be a better fit... but still, I think opening it with screw removal is the easiest option. It's only the one spring you've got to worry about, and its not too bad.

I have almost everything that can be attached to the front of the Dremels. They are my favorites, the big and the small one, even if I get criticized for them here in the forum

But the idea of the machine fascinates me.

I always approach it carefully, I can practice on the shutter parts of the dissection.

In any case, I will try to remove the shutter unit and tape it up. Then there will be no abrasion coming in.

I will have to fix it in place for this, I will see whether the vice with soft plastic jaws is suitable for this

The tungsten carbide cutters remove everything, the prerequisite is a stable, steady hand. Or the diamond cutters.

There is no point in trying to talk me out of having this very special fun

But in any case I will also consider dismantling the shutter.

A single targeted blow with the sharp cheese cleaver would be a sporty alternative

 

[ic-racer]

The cameras back together. Got a fright thinking the autofocus was now going weird but it was just the atrocious minimal focus distance of the 28-135mm lens.

I'm fairly sure this LCD connection will be more robust. It's like known stuff, zebra strips. I wasn't sure what to expect from that tape or how it really behaves. I've concluded the camera fixed so many times at this point that i've ran out of things to say to try cap it off, lol. I need to actually take some photos with it, but I wanna get the NiCd battery back together for that. It'd also give me time to let it sit and see if any problems occur before I've put film in it.

I had not know of the zebra connector until now. May I ask how it maintains contact? Is it sticky, do you use conductive glue , or are the parts just held together with pressure?

 

[ogtronix]

I had not know of the zebra connector until now. May I ask how it maintains contact? Is it sticky, do you use conductive glue , or are the parts just held together with pressure?

They're common in alot of LCD displays, usually the segmented or passive matrix style ones. Fancier displays have driver circuitry directly on the glass and I guess receive signals to the panel digitally encoded through fewer wires, so they go for heat seal/ anisotropic conductive film connections and flat flex cables.

But yeah they're just like relatively soft silicone rubber blocks with alternating columns of conductive and non conductive rubber material, such they can only conduct along one axis. The extra rubber on the sides is there for support to prevent the thing tipping over or squishing out. The connection is just made with pressure and the rubber conductive parts directly touching the ITO coating on the glass and the traces on the matching PCB, I assume with high resistance but you don't need much current getting through to drive an LCD. Finger oils getting in the way can supposedly prevent contact. It is a kinda sticky as a soft rubber, which is probably incidental, but it might help prevent the things walking out from vibrations.

They come across as a wacky solution to the "how do you connect stuff to glass" problem but as far as i'm aware they're amazingly reliable and long lasting. They come in all sorts of styles and sizes too, but they're really hard to buy if you just want One.

 

[Andreas Thaler]

Here I have a zebra from the LCD of the Nikon F3AF:

Tutorial Nikon F3(AF): Replacing the LCD

On the Nikon F3 and its versions, the LCD that is reflected in the viewfinder can fail partially or completely. Corrosion of the LCD connections could be a cause, or the LCD sandwich no longer seals tightly; black spots can also appear that make the digits unreadable. The only solution here is...

www.photrio.com

 

[Andreas Thaler]

And here is the cause of digits that gradually disappear. Progressive corrosion on the contacts to the conductive rubber:

Good

Bad

Nikon F3/T: LCD replaced

A project that has occupied me for years without being able to tackle it - for lack of a replacement display and know-how. Now it's implemented 😀 With my most beautiful F3/T (never used before), I had to watch the LCD display in the viewfinder slowly but steadily disappear. At first, only...

www.photrio.com

 

[ogtronix]

I have almost everything that can be attached to the front of the Dremels. They are my favorites, the big and the small one, even if I get criticized for them here in the forum

But the idea of the machine fascinates me.

I always approach it carefully, I can practice on the shutter parts of the dissection.

In any case, I will try to remove the shutter unit and tape it up. Then there will be no abrasion coming in.

I will have to fix it in place for this, I will see whether the vice with soft plastic jaws is suitable for this

The tungsten carbide cutters remove everything, the prerequisite is a stable, steady hand. Or the diamond cutters.

There is no point in trying to talk me out of having this very special fun

But in any case I will also consider dismantling the shutter.

A single targeted blow with the sharp cheese cleaver would be a sporty alternative

I'm a proud Proxxon Paisano. I got one recently for wet cutting glass with the flexi-shaft after my old 'Performance Power' tool wore out. I'm definitely looking out for excuses to use it.

I think power tools can be more controllable than hand tools alot of the time. They're doing most of the work so you can focus on holding onto it and making sure you're out of the way if anything were to slip or grab. One of my worst enemies (more so than those Dremel Dunderheads) is the dastardly needle file. It's just so easy to slip with them, to cut or pinch yourself on the exit burr, or to poke yourself when trying to support the rear end of it through a hole... which sucks since it deposits metal shavings deep into your tissues that must be dug out or bad things happen. I'm lucky I never gave myself sepsis or something.

Not to say power tools can't remove a limb or destroy a part at frightening speeds. Like there's a difference between owie fingers and the various industrial accident horror stories i've heard over the years with overpenetrating powder nail guns or naive guys hiring concrete saws. I set myself alight once with angle grinder sparks. I just don't buy the idea that hand tools are inherently more delicate or completely safe, especially since the lack of caution that encourages in people (myself!) can result in injury.


For holding the shutter in a vice, trying to grip it where the columns for the screws are would make sense. Like the two on the edge opposite the mechanism and have the dremel oriented so the cutting forces go down into the vice (rather than trying to pull the part up and out of it).

 

[ogtronix]

And here is the cause of digits that gradually disappear. Progressive corrosion on the contacts to the conductive rubber:

View attachment 389188

Good


View attachment 389189

Bad

Nikon F3/T: LCD replaced

A project that has occupied me for years without being able to tackle it - for lack of a replacement display and know-how. Now it's implemented 😀 With my most beautiful F3/T (never used before), I had to watch the LCD display in the viewfinder slowly but steadily disappear. At first, only...

www.photrio.com

Those gold traces on the LCD itself are odd, I've never seen that before. I like when cameras have weird early versions of more familiar stuff, like it's from an alternate universe where things developed slightly differently. It's reminding me that alot of what kicked this camera stuff off for me was seeing the surface mount PCB in a Polaroid SX-70 from the early 70s.

 

[ogtronix]

Big fan of every other listing for a focusing screen looking like this.

Some day PM screen is gonna eventually show up and it'll be listed exactly like this, and then be directly wrapped in parcel tape for postage.

 

[ic-racer]

And here is the cause of digits that gradually disappear. Progressive corrosion on the contacts to the conductive rubber:

Ok, now your thread on that repair from a while back makes more sense to me.

 

[Andreas Thaler]

Ok, now your thread on that repair from a while back makes more sense to me.

Thanks for the hint!

This saddens me, because as a trained public relations worker with many years of professional experience, I should be able to write clearly and understandably also here in the forum

 

[ogtronix]

Something I read on Dyxum was that you could use a focusing screen from a Pentax MX/LX shaved down a millimeter to fit in the 9000/7000 (and possibly the next i generation).

The 7000's screen measures 35.8 x 24.0 x 1.6mm and the LX's measures 35.4 x 24.9 x 1.2mm.

Filed and abraded 0.5mm off the top and then 0.5mm off the bottom, only slipping and gouging the front of the screen once!

Pentax screen compared with the original Minolta. The Pentax screen is considerably dimmer and grainier, the wedge is hard to use with the narrower open apertures on standard zoom lenses, and the autofocus doesn't quite agree with the wedge. Maybe shimming it could make them line up, but I think the dimness in particular is a little disappointing.


In other news I got another 9000 AF with the usual problems, it showed up cheap with a Program Back Super. I've been wanting to take a look inside one but didn't want to risk breaking the only one I have. There's an old youtube video with a guy called Gary Friedman showing off his favourite Minolta cameras, where he'd stuck a switch in a Program Back Super disable it quickly and let the normal camera functions take over, a feature that seems a good idea, but i've found no further info on how it was done.

The other thought is how i want to try stepwise document a 9000 repair. Could be fun to try do it on film with a digital backup.