M645 (original) shutter issue

[maderik]

My Mamiya M645 is having shutter issues. When either shutter release is pressed, the shutter opens and does not close until the battery check button is fully depressed. This happens with old batteries, new batteries, lithium/silver/alkaline batteries, finder on/off, lens on/off, using the finder speed dial or the body speed dial, and mirror locked up (so not sticky foam.) The battery check light works and the metered finder works. It's as if the shutter itself is not getting power although the rest of the camera is. Does this sound familiar to anyone and has a known fix? I don't mind opening up the body but I'd like to know what I'd be looking for. In theory, I can still use it with the 70mm leaf shutter lens as my shutter but ...

--
Erik

 

[Mike051]

I'm having the same problem with my Mamiya 1000s. I've got two Mamiya 645 Super bodies in excellent condition,
but would very much like to be able to use my old 1000s too.

 

[BMbikerider]

I bet that no more than a damn good service will get them up and running again. I may be wrong but the electonic shutters depend on magnets to work and these after a time become 'sticky'. Cleaned up they soldier on.

 

[maderik]

Sticky magnets usually mean slow high speeds and/or occasional hang ups. I've seen & fixed sticky magnets on 35mm cameras (common issue on Olympus OM models w/electronic shutters) and this feels different. But if I open mine up, it's worth checking this theory out.

 

[snederhiser]

Hello;
I have a M645 and a 1000s. Tore into the M645 because of flash sync problems. I believe that you are having a shutter switch issue. The screw that secures this switch comes loose and skews the switch. Remove the wind knob and peel the leatherette off. This will give you access to the screws that hold on the side panels. I would recommend getting a repair manual on this, Steven.

 

[maderik]

Well, I opened mine up and found my problem. The second curtain is closed when a solenoid punches a lever. My solenoid was firing but with just a pathetic tap instead of a punch. The trip pressure needed was not excessive and I could not find any corroded wires or dirty contacts, so it appears I have a failed solenoid.

 

[snederhiser]

Hello;
Check the capacitor in the circuit, this gives the punch to the solenoid. Steven.