[Beepaitch]

I've just picked up an MX. Wanted one for a while and it seemed a fair deal. It wasn't, it's in a pretty bad state grime-wise, and it was sold-as-seen so I can't return it - and just to get this out the way, I can't justify/afford a 'proper' CLA right now and it's so battered I'm not sure it deserves it!
So before I chalk this up (down?) to experience and flog it for spares or give it to my 4 year old to use as sandpit toy (jokes!), I'd like to try and clean it a bit myself, gain some experience and maybe even be able to use it!

Some info on condition:
- Mirror foam is shot and hanging down. I've ordered replacement foams and seals.
- Practically every surface is dented, scratched, rusted or brassed.
- The Mirror locks up about half of the time, at most speeds, I've not been able to find a pattern yet. I'm pretty sure it's not the sticky foam holding it up because to get it back down again I have to either wind it again and fire, or manually take the lens off and reset the lever on the left of the Lightbox with my fingernail.
- I've taken the base off, and there is a lot of dust, greasy foam particles etc.
- I ran a short roll through and nearly all the photos seem to have only part of the frame exposed so there must be some shutter curtain sync issues I guess.

Firstly I'd like to get the gearing in the base clean (pic attached). When it comes to cleaning this area up, would it be best to dissemble the whole mechanism and clean each part, or can I maybe gently flush the gears through with alcohol, dry everything, and re-lube them with a tiny amount of light oil afterwards?

I've searched around quite a lot, and every time someone asks similar questions they answer is "get a CLA". So assuming I'm definitely not getting a CLA, what advice would you give me?

Attached Images

 

[photoptimist]

I've just picked up an MX. Wanted one for a while and it seemed a fair deal. It wasn't, it's in a pretty bad state grime-wise, and it was sold-as-seen so I can't return it - and just to get this out the way, I can't justify/afford a 'proper' CLA right now and it's so battered I'm not sure it deserves it!
So before I chalk this up (down?) to experience and flog it for spares or give it to my 4 year old to use as sandpit toy (jokes!), I'd like to try and clean it a bit myself, gain some experience and maybe even be able to use it!

Sounds like a wonderful plan. Restoring old gear to working order can be a very engaging and rewarding hobby.

Some info on condition:
- Mirror foam is shot and hanging down. I've ordered replacement foams and seals.

Yes, that's a key part of most CLAs for older cameras.

- Practically every surface is dented, scratched, rusted or brassed.

Surface wear is usually not a problem unless a dent impinges on a part of the mechanism or has distorted the body.

- The Mirror locks up about half of the time, at most speeds, I've not been able to find a pattern yet. I'm pretty sure it's not the sticky foam holding it up because to get it back down again I have to either wind it again and fire, or manually take the lens off and reset the lever on the left of the Lightbox with my fingernail.

Chances are that this is is due to "a lot of dust, greasy foam particles" that you mentioned.

- I've taken the base off, and there is a lot of dust, greasy foam particles etc.

This is a likely root cause of the problems. Dust and greasy foam bits are probably also in the shutter, mirror, or aperture mechanisms which is preventing or slowing the full travel of these parts and the smooth operation of the mirror reflex motion.

- I ran a short roll through and nearly all the photos seem to have only part of the frame exposed so there must be some shutter curtain sync issues I guess.

That's a sure sign that the shutter curtains are not traveling as they should. It could be due to accumulated gunk in the guideways or in the curtain roller mechanisms. Carefully watching the curtains as you wind the camera and fire a long-shutter-time shot (1 second or B) may show you what is going on.

Firstly I'd like to get the gearing in the base clean (pic attached). When it comes to cleaning this area up, would it be best to dissemble the whole mechanism and clean each part, or can I maybe gently flush the gears through with alcohol, dry everything, and re-lube them with a tiny amount of light oil afterwards?

I'd first try a spot cleaning of all the accessible surfaces (and cleaning those parts as you slowly/partially cock the shutter and rotate all those gears). Flushing the mechanism seems risky because it might wash dirty solvent into other parts of the camera. A full disassembly may be needed but that requires incredible attention to detail to document EXACTLY what parts, in what orientation, came from which part, and in what order. The chances of misplacing, dislocating, or mis-rebuilding is very very high unless you are the type of person who is very good at keeping track of every last little tidbit. (Pro tip: do not disassemble a camera or lens in a room with shag carpet! )

I've searched around quite a lot, and every time someone asks similar questions they answer is "get a CLA". So assuming I'm definitely not getting a CLA, what advice would you give me?

Good luck and have fun with your adventures in gear restoration!

[AstroDave]

Take a vacation to Puerto Rice and have a visit with ismaelg (ismaelg - View Profile - PentaxForums.com)?

[dsmithhfx]

The Mirror locks up about half of the time, at most speeds

It's a common issue, and (I've been reliably told) you will want a real cla to fix (ISTR shutter curtains not in sync).
Spotmatic SP mirror malfunction - PentaxForums.com

If it's a tosser anyway, you can descend into the nightmare demimonde of camera disassembly, risking only your sanity.

[Beepaitch]

Thanks for the replies. I spent some time brushing lighter fluid (this was probably the wrong stuff! But seems less destructive to old plastic than Isopropyl) around most of the gears and pawls with camera on it’s side and upside down to try and a make sure none dripped inside the body, wiping the brush on a cloth, and removed a load of small fragments which can be seen on cloth and in pot of fluid. I dabbed it dry as well as could and blew it dryer. Now the mirror doesn’t lock up at any speed 🤷🏻*♂️

But… I might have killed something. Bulb setting doesn’t work, it fires at about the same speed as a 1/60th I’d say. In fact all the speeds under about 1/60th seem to fire at same speed. Interesting!

[Beepaitch]

Just to check, I stuck the MX on a DIY shutter speed tester I made a while back. The tester isn't accurate, some issue with my code, but it does show that every speed slower than 1/60th including Bulb is the same. Speeds over do - roughly - increase as they should.

[pentaxus]

My guess the mirror issue has to do with the second curtain travel time being too slow. Probably anything that moves and is visible with the bottom cover off needs a drop of appropriate oil. NYE oil is good as is Deoxit X10s oil in an oiler bottle. I'm not sure how available these are where you live. The other issue is that even if you get it going you probably need test equipment to get things working properly.

[dsmithhfx]

My guess the mirror issue has to do with the second curtain travel time being too slow. Probably anything that moves and is visible with the bottom cover off needs a drop of appropriate oil. NYE oil is good as is Deoxit X10s oil in an oiler bottle. I'm not sure how available these are where you live. The other issue is that even if you get it going you probably need test equipment to get things working properly.

This is what I'm talking about. I applied Beepaitch's fix (cleaning and greasing gears exposed by removing the bottom plate), and it seemed to work for several years, maybe 3 or 4. Until it didn't. Since I rarely if ever shoot at speeds lower than 1/60 I can't speak to the other thing which (I guess) is pointing to the slow 2nd shutter curtain issue. I do think a trip to the shop is about the only reliable way to resolve it.

[vladimiroltean]

But… I might have killed something. Bulb setting doesn’t work, it fires at about the same speed as a 1/60th I’d say. In fact all the speeds under about 1/60th seem to fire at same speed. Interesting!

Maybe your speed selector cam got misaligned? I made a short video showing what the positions should be, maybe it's helpful.

You Tube

You Tube

[Beepaitch]

Maybe your speed selector cam got misaligned? I made a short video showing what the positions should be, maybe it's helpful.
https://www.youtube.com/watch?v=6JFtncHidME

Thank you! I’m assuming you just recorded this. Extremely helpful as it’s shown me that the spring L-shaped part isn’t returning on mine at all, and several of the levers are in quite different positions. It wasn’t like this until I brushed it with solvent. I’m going to try slow down your vid and see exactly what moves when the winder is advanced.

[vladimiroltean]

Yes, I just removed the bottom cover to record this. Let me know if you need a close-up picture of something.

[dsmithhfx]

Thank you! I’m assuming you just recorded this. Extremely helpful as it’s shown me that the spring L-shaped part isn’t returning on mine at all, and several of the levers are in quite different positions. It wasn’t like this until I brushed it with solvent. I’m going to try slow down your vid and see exactly what moves when the winder is advanced.

I didn't pick up on the lighter fluid thing. Yeah, it's great for cleaning, but it's totally not a lubricant! Once it dries, it's like all the lubricant has been stripped off. You'll need to put a few drops of light machine oil (e.g. 3-in1) on those gears. Found out about this the hard way when I used lighter fluid to clean up a lens diaphragm -- which I haven't put oil on, waiting to obtain a proper (graphite?) lube for this particular application.

[Ray-uk]

waiting to obtain a proper (graphite?) lube for this particular application.

Try a soft pencil (2B or 3B), although most aperture assemblies shouldn't need lubrication.

[Beepaitch]

… Once it dries, it's like all the lubricant has been stripped off. You'll need to put a few drops of light machine oil (e.g. 3-in1) on those gears ...

Thanks again, I waited for some suitable light oil to turn up, and put microdots on each moving part I could see, and within a couple mins it now winds on properly and all the slow speeds apart from BULB work!

Pretty sure the curtain sync probs will still be there, but will test this asap with a very short roll.

[dsmithhfx]

Try a soft pencil (2B or 3B), although most aperture assemblies shouldn't need lubrication.

This one does for sure. Located a suitable candidate (extra fine graphite in a tube) at Canadian Tire for a reasonable price.