Hello,
I have been busy the last couple of weeks, so I haven't had time to play with the F4.However, now I have loaded the camera with film,closed the back and the film advance worked,the autofocus works and the shutter release works! I suspect that when I rewound the last roll of film,I maybe inadvertantly pressed a button I shouldn't have and that locked the shutter mechanism.I still have a few shots to go before re-wind, stay tuned and see what happens!
Cheers, Pino

I'm not familiar with the F4, but shouldn't there be a mirror lockup for the crazy invasive fisheyes?

Are you sure you haven't triggered that by mistake?

It fired with the door open?

Stick a roll of film in the camera and load it. Close the back and see if it works.

Then if it works rewind the roll.

framer

Hello framer,the flipper by the R2 button was already up. I opened the film door and was able to operate the shutter release button whilst the back was open but when I shut the back the shutter would not fire. Very strange.
Cheers, Pino.

OK, I got an idea! Check the flipper by the R2 button on the back. If it's down move it up. Opening and closing the film door should return the flipper to the up position. This will cause the condtion you stated.

Good Luck

framer

Hello again.Here is the latest. I cleaned all the contacts with isopropanol as suggested.The viewfinder is not black, I can see the subject. I am using battery pack MB-20.I switch camera on by pressing the lock release L to position S.When I lightly
press the shutter release button the viewfinder LCD lights up displaying my settings. When I fully depress the shutter release button, nothing happens,no autofocus,no shutter release,only the alert LED blinks red.I also set focus to manual and focussed the lens manually, the green focus LED lit up but still no joy!
Cheers, Pino

Make sure all the batteries are in correctly. It's easy to have one in backward in the grip.

Also try to set focus to manual, focus manually. If the auto focus motor doesn't work the shutter might not fire if out of focus.

framer

If nothing else works look for a used body w/o a viewfinder or broken meter. I got a nice body for under $100 that got my F4 back to 100%.

framer

This is not the same problem as on the F5 is it? And, you might remove the battery grip, clean all these contacts with isopropyl alcohol as well. Actually, what might work even better is to obtain some electrical contact cleaner from a local hardware store and spray the contact cleaner on either a Q-Tip or small cloth, sing this to clean the contacts. Do not spray the cleaner any where near the camera, however.

And of course, check the release on the battery grip to make certain no problem exists here.

as spraynpray suggested check the viewfinder. also it's a good habit to clean the battery contacts once in a while - just get some izopropylen alcohol and some cotton swab and clean it (or use a dedicated contact cleaner lotion).

Can you see the subject or is the viewfinder black? 'The shutter locks' could mean mirror up, shutter open or it could mean the button is locked i.e. the shutter will not release. More info please?

Hello,I suspect I have a locked shutter on the F4. The batteries are brand new and the viewfinder LCD appears with all the relevant information except for the green focus dot, it is red instead. When I press the shutter release button nothing happens, no autofocus, only the viewfinder LCD lights up and the alert LED blinks red.The manual states "in Single Servo Autofocus, if in-focus indicator LED does not appear and X appears,shutter locks" My question is,how do I unlock the shutter? Any help from the very knowledgeable people on the Forum would be appreciated.
Cheers, Pino.