RB67 ProS shutter not firing (revolving back issue it looks like)

[Athiril]

Have had my RB67 ProS for quite some time.

It's been pretty good so fire, firing in both normal and portrait rotations, then portrait rotations weren't firing (shutter was like its locked, wont press in).

Now it does it sometimes in normal orientation too.. more often then it used to, I did tighten up the screws on the locking mechanisms that hold film back in place as they were getting loose.

It's a revolving back issue I think, as if I remove the revolving back there is no issue in firing it, whether the film back is attached to the revolving back or not does not affect it, and the back offers no resistance when I press the switch in it with a pin that 'fires' it and pops the red tab out.

I'm not sure what happened, as the holes the shutter peg things stick into in the revolving back havent changed size, so I can only imagine I need to tighten or loosen the relvoling back screws inside those holes?

edit: now that i take a closer look it seems like the bottom right pin is offering resistance when i push it (the one that fires the film back counter in portrait mode, but it looks like the body also engages/locks with it in normal mode too). It doesnt look dirty or anything.

Lubricating it seems to be having portrait mode firing now, but not normal orientation.. i always had more trouble with portrait.. odd

edit2: seems like one of the dark slide locks has a sliding cover over that firing hole, that seems to get stuck, pushing it back with a tooth pick then pushing the lock the dark slide engages seems to get it working flawlessly now.. seems like I need some lubrication for these moving parts.

 

[epatsellis]

Tear it down, clean all the old lube, reassemble and lube with a high quality dry lube (bike shops are a good source), reassemble and shoot for the next decade or so...

 

[Athiril]

I was wondering what kind of lube to use, thanks

The foam seals are also all either gone or like sticky liquid, but I havent had a single light leak, so I didn't want to fix what wasn't broke.

 

[Andrew K]

this may not seem high tech, but use fishing reel grease (I learn't this while working for the biggest camera repairer in Melbourne) on the rotating surfaces of the rotating back (but not too much!)

you can also lube the moving pins with the smallest amount of oil (doesn't matter what kind, as you're not using much!) - I use watchmakers oil, but you can use any good slightly thickish oil

And if you are going to the trouble of servicing the back then replace the seals - it's a normal part of a back service....

 

[Athiril]

I've never changed seals before... theres basically none left on the back anyway though.. Id have to scrape out the remains lol

And find somewhere to buy the foam + glue from.


I bought some small bottle of $15 bicycle lube from a bike shop I found on Albert st while up here in Brisbane, it's a 'superior dry lubricant' that repels dust and dirt and stuff and is not supposed to build up gunk so I got that one, its all working flawlessly now

 

[danegermouse]

changing the seals is a lot easier than you might expect. a light leak is waiting to happen so best to do it ahead of time. there's a guy called "interslice" on ebay that sells pre-cut kits and he will email you a pdf of the instructions. i think they cost about $10 delivered. i bought a full foam kit from him a few years back and have done three 35mm camera bodies and my rb body, mirror and two backs. i still have heaps of foam left too. i dont think he sells the full kits anymore but pre-cut saves a lot of hassle. the ones that need glue are self-adhesive too. very easy, highly recommended.

 

[Athiril]

Hmmm... I cant see a light leak really happening since it hasnt already, since the state of the foam of whats actually left is thin and gooey, most of it's already actually gone (on every part of the camera, back, mirror, etc).

Though since its only $10 ill order one next week when I get $ again