Nikon F4 Exposure Lock stuck in on mode

[Scott Micciche]

I have had this body for years and it's always been flawless until today. The exposure lock button is stuck in the engaged position, it is a button I only use on occasion. Decoupling and coupling the AE AF doesn't do much as does repeated depressing of the button.

I have been looking for diagrams or howtos on taking this section apart to clean the contacts before hunting for another body. I'm also unable to find a repair shop willing to diagnose the body or it will just be cheaper to find another body.

Regardless, if anyone has any insight, I would appreciate any information.

Thank you.

 

[shutterfinger]

Factory service manual is available at http://arcticwolfs.net/
Fig. 8 spring 1K220-228 is the likely cause.

 

[Scott Micciche]

Thank you for this, my button does feel springy, as if it does depress and release, so I didn't focus on it but it could be. I was going to use some isopropyl 99% alcohol but I don't think it would penetrate the actual contacts of the button.

 

[shutterfinger]

It looks like the button is threaded on the rear so a nut or plate is there for it to screw into. Being it has spring action and the button returns to "normal" position says the it has unscrewed some leaving the contacts made or the electronics have failed. I would press in on the button and turn it clockwise until it will no longer turn or if it will not turn I would start looking at the electronics bu removing the batteries, turning the power switch on and operating every button on the body holding each for 15 seconds to discharge any capacitors then put the batteries back in and check the camera.

 

[Scott Micciche]

Thank you again. I tried screwing and unscrewing the button, batteries are now out for the night. I do hear the button "click" like the other button above. It might be the electronics. I might have to find another body. Damn and I have 10 shots left on a roll ... it will be sunny 16 for those then

 

[shutterfinger]

Operate the lever above the AE lock from AF lock to AF/AE lock and back several times.

 

[fstop]

At least it doesn't make a ping sound when you release the shutter.

 

[Scott Micciche]

I've operated the lever, left some alcohol in the buttons overnight and activated. The EL is still stuck, so I am thinking it's the electronics within the body. It might be cause from such infrequent use as I rarely use the button aside from accidentally pushing it. Thanks for all the help, if it does deactivate, I'm not sure I could trust the button.

 

[shutterfinger]

Download the pdf's you need for your F4 at https://drive.google.com/drive/folders/0B1sPJkp-Mdghcm5jU0RvUmRmVE0?usp=sharing
Looking at the F4s the troubleshooting flow chart shows that the shutter prerelease may not be releasing causing the exposure to stay as if the exposure lock is set.

 

[Scott Micciche]

I grabbed the PDFs and wow those are interesting. I need to see how to remove the bottom plate and do some testing. I may as well since I cannot get it to function properly.

 

[Scott Micciche]

I wanted to follow up on this problem with the F4 stuck AE lock button.

I saturated a cotton bud with DeoxIT D5 and let is soak into both buttons overnight with the camera on it's side.

The button now works as expected and it no longer sticks.

There must have been some corrosion within the switch (hopefully).

I'm going to run a roll of expired film through it and see how it reacts over a week's time. Previously, if the button worked for a bit, by mid-roll, it would lock in AE and that was the end of metering.

If something else changes, I'll update the thread.

 

[vlasta]

Nice to see problem solved

 

[Scott Micciche]

Nice to see problem solved

Me too. The F4 is one of my favorite bodies and apparently, I need to use the AE-L button more often.