mirror sticking on MZ-7

hi

my girlfriends MZ-7 started misbehaving last weekend. it'll be fine for a few frames, then the mirror will remain up after the shutter has closed. the film doesn't advance... the whole things just jams up. the mirror can be pushed down again by hand, but just flips back up. once the mirror is in this position, the camera is totally unresponsive. if the batteries are left in the camera while the mirror is 'up', something gets very very hot inside the body, including the batteries. the only way to get the mirror down again is to leave the camera for the best part of a day with no batteries in. after this, once the batteries are replaced, the mirror pops back down, the film advances and it's all back to normal, but only for a few more frames before it all starts happening again.

any ideas??

many thanks...
chris

Was the camera cooler/colder than usual? I've had the Spotmatic family's lubrication thicken/gum up in cooler weather, and have sent the bodies to be serviced.
I don't know the age of your lady's MZ, but would this be a possibility?

Cheers

I don't think this will be the problem in the MZ's. Any SLR works on a dominoe effect. When you trip the shutter, you start a chain of events with each event triping the next one when it is finished. ie. Shutter press - mirror up - first curtain - second surtain - mirror down - rewind unlocked - wind to cock shutter and release shutter lock. If any of these fail the cycle won't complete and the same can happen if the cycle gets out of synch. Older the older mechanical cameras it is fairly easy to go through tripping all the releases until you find where the problem is or to put it back into synch. With the more recent electronic cameras, the principle is the same but it tends to be electrical switches and motors. I would suspect a switch is not making contact properly and the heat is because a motor is overrunning. Once any power is left off for a time, the sequence resets itself and so starts working for a while.

However, this is only supposition. I am quite happy to fiddle with the older mf cameras but at this level it is an experts job.

Kim

One reason I don't like lots of electronics in cameras is this sort of thing. If the problem is not down to a dirty switch contact or a dry solder joint, it is extremely difficult to fix a problem like this, and I am expert in electronics!

I havent stripped an MZ, but I doubt the mirror is motor driven. Usually even with electronic cameras the shutter and mirror are still spring driven. The shutters are released using little electromagnets to activate the the mechanical latches that hold them cocked. The rest is mechanical, as in a manual camera.

I suspect that what may be happening is that the shutter is not being cocked due to some mechanical problem. This would explain the stuck mirror, as mirror drop is triggered by the closing shutter.

This could explain the heating effect, if the camera is waiting for a signal that the shutter is cocked before it switches off the electromagnets to fire the shutters.